Patent Application
20130225986
All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
Embodiments described relate generally to medical imaging and methods and devices for ensuring adequate quality and coverage of scanned and recorded images. In another aspect, embodiments described relate to reducing review time of scanned and recorded images from an imaging session or procedure.
Medical imaging is typically referred to as Radiology because of the historical use of radiation-based imaging techniques to view internal structures of the human body. The origin of radiology is traditionally credited to Wilhem Rontgen, a German Physicist who discovered X-radiation (electromagnetic radiation in the 0.01 to 10 nanometers and with an energy levels ranging from 100 eV to 100 KeV) in 1895 as a result of his research on cathode ray tubes. Dr. Rontgen discovered that radiation emitted from the cathode ray tubes could pass through some forms of human tissue with varying degrees of absorption and that the X-radiation could expose photographic film. One of his first experiments was the now famous image of his wife's hand showing the bones of the hand with her wedding ring suspended as a halo around the proximal phalange of the third finger. The medical implications of viewing internal body structures were apparent and Dr. Rontgen was awarded the Nobel Prize for Physics in 1901. Viewing the internal structures enabled radiologists to detect and diagnose conditions without the need for exploratory surgery, or before the conditions worsened and further compromised the patient's health. The applications of medical imaging have expanded as imaging technology has advanced. In addition to the singular X-ray presentations, multi-slice computed tomographic (CT) X-ray images are now standard tools for the radiologist. Imaging technologies that employ other energy sources, such as magnetic resonance imaging (MRI), radiation scintillation detection, ultrasound, and others have also expanded the radiologist's capabilities in diagnosing and detecting physiologic conditions.
For the advancement of these devices and methods to demonstrate utility for the medical imager, that is, for these new devices and/or methods to be adopted into the practice of radiology, they must demonstrate effectiveness and efficiency.
Effectiveness is the ability for the device or method to image internal structures and present the image viewer sufficient information on the internal structure to make a medical decision. If a radiologist wishes to examine the knee joint of a patient presenting with complaints of pain, the effective imaging device or method will be able to distinguish the internal structures of the knee in a way that will allow the radiologist to determine the nature of the complaint. If it is a fractured bone, the image must display, in some fashion, both the bone and the fracture. If it is a torn meniscus, the image must display, in some fashion, the bone structure with the attached meniscus, and the tear in the meniscus.
Efficiency is a measure of the resources required to perform an effective procedure. If a device or method can replicate the effectiveness of an existing device or method and, because of an advance in materials, manufacturing method, or other factors lower the cost of the device, then the decreased cost in performing the same function, or increase in efficiency, is a useful feature of the advancement. If a device or method can replicate the effectiveness of an existing device or method and, because of an advance in the functional design can reduce the overall time required to perform the procedure, or if that advancement can shift the time requirements away from more highly trained and skilled personnel to less highly trained and skilled personnel, then the resource shifting is an increase in efficiency which is a useful feature of the advancement.
Embodiments described herein provide for devices and methods for recording manually-obtained medical images so that they may be reviewed at a later time. The term “manual” is non-limiting and includes utilizing a device in which the image detection mechanism is designed to be used when held by the human hand. Some embodiments are directed to solving the problem of recording scans that adequately capture information needed for a physician or other trained reviewer to properly screen or diagnose a patient. For example, some embodiments provide for devices and methods for alerting an ultrasound operator if the distance between scanned images exceeds a maximum distance. In such cases, the operator will be alerted to rescan to ensure completeness of the imaging.
Further embodiments provide for effective and efficient devices and methods that allow the images recorded from a scan to be reviewed by a highly trained physician in an environment where he or she is not likely to be distracted by patient interaction or instrument adjustments, which improves the accuracy of the diagnostic and detection capabilities of the physician. Where an operator is not the ultimate reviewer of a scan, some embodiments described reduce the review time expended by reducing the number of images for review or the amount of time allocated for each image in the review. In such cases, these devices and methods allow the more highly trained image reviewer to be uncoupled from the time-consuming aspects of image acquisition and focus on the tasks associated with image interpretation and allows the operators to benefit from the reduction in time consumed by more highly skilled personnel.
There are many applications for medical imaging, but cancer screening and diagnoses are significant applications in the field. The clinical evidence is clear that early detection of cancerous lesions saves lives, and medical imaging is one of the foremost methods used to find cancerous lesions before the patient's condition becomes symptomatic. Embodiments described provide for devices and methods for recording and reviewing medical images for the purpose of diagnostic and screening image review. Applications of the described embodiments include use in screening and diagnosing many cancer types, such as cancer of the prostate, liver, pancreas, etc. Although the discussion below may reference breast cancer detection for describing embodiments and aspects of the invention, it should be understood; however, that the device has utility in the early discovery of other types of cancers and that omitting those cancers from this discussion does not limit the scope of the current invention. Moreover, the described embodiments are applicable to medical imaging in general and are not limited to any specific application provided as an example herein.
It is estimated that one out of eight women will face breast cancer at some point during her lifetime, and for women age 40-55, breast cancer is the leading cause of death. While methods for detecting and treating breast cancer initially were crude and unsophisticated, advanced instrumentation and procedures are now available which provide more positive outcomes for patients.
For instance, several studies have demonstrated that the ability to detect breast cancer tumors in advance of physical presentation (that is, before the discovery of a palpable lump or the appearance of a physical change in the breast's shape or appearance) has reduced breast cancer related mortality by as much as 30% (Tabar L, Vitak B, Chen H H, et al. The Swedish Two-County Trial twenty years later: updated mortality results and new insights from long-term follow-up. Radiol Clin North Am 2001; 38:625-51—IARC Working Group on the Evaluation of Cancer Prevention Strategies. Handbooks of Cancer Prevention, vol. 7, Breast Cancer Screening. Lyon, France: IARC Press, 2002.
—Tabar L, Yen M F, Vitak B, Chen H H, Smith R A, Duffy S W. Mammography service screening and mortality in breast—Shapiro S, Venet W, Strax P, Venet L, Roeser R (1982) Ten to 14-year effect of screening on breast cancer mortality. J Natl Cancer Inst 69:349-355). Duffy demonstrated a clear correlation between the size of the cancer at the time of discovery and the survival rate (Stephen W. Duffy, MSc, CStat,* Laszlo Tabar, MD, Bedrich Vitak, MD, and Jand Warwick, PhD, “Tumor Size and Breast Cancer Detection: What Might Be the Effect of a Less Sensitive Screening Tool Than Mammography?” The Breast Journal, Volume 12 Suppl. 1, 2006 S91-S95)
Some of the reasons early detection leads to more positive outcomes is because that smaller tumor respond more positively to medical treatments, such as chemotherapy and radiation therapy and the smaller tumors are less likely to have metastasized to the lymph nodes and distant organ structures. In addition, smaller tumors are more easily excised in their entirety, reducing the probability of residual in-vivo cancer cells multiplying to the stage where metastasis can occur.
Advances in tumor detection procedures have radically changed the course of diagnosis and treatment for a tumor. With the advent of imaging devices, such as the mammogram, suspect tumor may be located when it is of relatively small size. Today, the standard of care in tumor detection generally involves both a mammogram and a physical examination, which takes into account a number of risk factors including family history and prior occurrences. Technical improvements in mammogram imaging include better visualization of the breast parenchyma with less exposure to radiation, improvements in film quality and processing, the introduction of digital technology, improved techniques for imaging, better guidelines for the diagnosis of cancer and greater availability of well-trained mammographers. With these advancements in imaging technology, a suspect tumor may be detected which is 15 mm or smaller. This is compared with the 25 mm average size of a tumor which is discovered by physical palpation or other symptomatic presentation. More recently substantial progress has been witnessed in the technical disciplines of magnetic resonance imaging (MRI) and ultrasound imagining. These devices and methods have demonstrated the ability to reduce the average size at which cancers are detected. In the field of breast cancer screening, these reductions have been generally reduced to averages below 10 mm. With these advances, the location of a lesion is observable as diagnostic or therapeutic procedures are carried out.
Ultrasound has demonstrated particular utility in the detection of breast cancer for several reasons. Since the technology is an emission-reflection-detection technology rather than an emission-absorption-detection technology, as is the case of the mammogram, and since the sonic energy source transmits in multiple frequencies, each frequency interacting with the tissue differently, ultrasound is not as subject to shadowing phenomenon as is X-ray. Ultrasound is also one of the most prominent manual imaging technologies. That is, rather than the energy transmission and detection structures being mechanically fixed in place by other structure, the transmission and detection mechanisms are packaged in a single device which may be held in the human hand. The portability and small size of the device means that it can be used in locations, both geographic and anatomic, that are difficult for larger, more expensive imaging devices such as X-ray and MRI.
Because of ultrasound's superior capability, compared to mammography, in distinguishing between benign glandular tissue and malignant glandular tissue in the breast in women with a greater ratio of glandular tissue to fat (a condition termed “dense breasts”), ultrasound demonstrates a greater utility in cancer detection and diagnosis in these patents. Kolb (Kolb T M, Lichy J, Newhouse J H (1998) Occult cancer in women with dense breasts: detection with screening US—diagnostic yield and tumor characteristics. Radiology 207:191-199 and), Kaplan (Kaplan SS (2001) Clinical utility of bilateral whole-breast US in the evaluation of women with dense breast tissue. Radiology 221:641-649), Berg (Wendie A. Berg; Jeffrey D. Blume; Jean B. Cormack; et al., Mammography vs. Mammography Alone in Women at Combined Screening With Ultrasound and Elevated Risk of Breast Cancer, JAMA. 2008;299(18):2151-2163 (doi:10.1001/jama.299.18.2151) and Kelly (Kevin M. Kelly, MD, Judy Dean, MD, W. Scott Comulada, Sung-Jae Lee, “Breast cancer detection using automated whole breast ultrasound and mammography in radiographically dense breasts”, Eur Radiol (2010) 20: 734-742) all demonstrated dramatic and significant increases in the number of cancers, with respect to mammography, in the population of women with dense breasts.
Medical imaging applications may be generally considered to fall in to one of three categories: (1) screening of asymptomatic patients, (2) diagnostic evaluation of symptomatic patients (i.e., those presenting symptoms discovered through the screening process, or outside of the screening process because they did not participate in a screening program or the screening program failed them), and (3) guidance for therapeutic procedures (i.e., those patients whose symptoms were confirmed, by the diagnostic testing process, to require some form of treatment). The clinical needs for each of these applications differ significantly, as do the needs, applications, and methods of the imaging techniques used in the three procedures.
In the diagnostic and guidance procedures, there is suspicion that a particular anomaly may be malignant and the status of that anomaly must be clarified (as is the case prior to a diagnostic procedure) or there is confirmation that an anomaly is malignant and that anomaly must be treated (as in the case of therapy). In both cases the ability to map the location of the anomaly is critical, but the ability to map the location of surrounding tissue is less critical. In both cases, there is positive identification of something abnormal in the patient's tissue and the subsequent actions are addressed to examining that abnormality, not to the normal surrounding tissue.
In the diagnostic examination the physician is already concerned with, and desires to characterize, a particular structure which has been previously characterized as “abnormal”. In the case of the suspected breast cancer the suspected abnormality is typically a result of a physical finding, such as the physical palpation of a lump in a particular location in the breast, a complaint of pain in a particular location in the breast, the appearance of some sort of deformity, such as skin thickening, skin distortion, abnormal nipple discharge, or the appearance of an abnormal structure on a screening imaging examination, such as a mammogram. Prior to the diagnostic examination it is typical that the region of interest is only identified as “suspicious”, not as a cancer. It is the purpose of the diagnostic examination to determine whether that “abnormal” region of interest is benign, malignant, or warrants further examinations to characterize more thoroughly. The position of the structure is known because it has been previously identified by one or more of a variety of methods described earlier. Therefore, the physician expects to find the abnormality.
In the diagnostic examination the physician is not concerned with structures other than the identified region of interest. In the example of breast cancer, the diagnostic examination is not only confined to the particular breast in which the abnormality was identified, but it is confined to the one particular quadrant of the particular breast in which the abnormality was found. There may be abnormalities in the other seven quadrants (there are four quadrants per breast). There may even be cancers in the other seven quadrants, but it is not the purpose of the diagnostic examination, however, to find those possible, but previously not identified, lesions. The purpose of the diagnostic examination is to characterize known lesions in known locations.
The screening examination differs from the diagnostic examination because (1) it is performed on an asymptomatic patient (that is, a patient who is considered healthy), so the physician expects all of the internal structures to be normal, and (2) it is performed on the entire structure, not just a localized area with a predetermined abnormality. As stated here, the physician expects normal tissue because the patient is asymptomatic, but he or she also expects normal tissue because the vast majority of patients have no abnormalities. In the case of breast cancer screening in the United States, only 3 to 5 patients per 1,000 screened have cancer. Only 1 in 10 have any tissue structures considered “not normal” enough to warrant further examination.
The contrast between screening and diagnostic can be exemplified in the mammography process. Since the expectation is that there is no cancer, there is no suggestion that a cancer is more likely to be in one quadrant rather than another. In the screening examination the Mammographer will compress the breast tissue between two paddles to pull as much of the breast as possible away from the chest wall to bring that tissue within the field of the X-ray source and X-ray detector. The X-ray source and X-ray detector are fixed in space and the patient tissue is immobilized within the field of exposure. The process requires significant patient manipulation and tissue distortion to pull the mammary tissue as far into the field of view of the X-ray radiation emitting and detecting imaging device as is possible. Since the X-ray radiation passes through the entire breast before exposing the detector, the image is a collection of “shadows” of structures within the breast and the entirety of the three-dimensional structure of the breast is reduced to a single two-dimensional image. The radiologist can tell with a single view whether the mammogram represents the entire breast.
In the diagnostic mammogram it is common for the mammographer to compress only portion of the breast which contains the region of interest. These “spot compressions” are often accompanied by magnification, with the result that only a portion of the breast appears in the image. Since the radiologist is not concerned with these other regions in the diagnostic examination, however, the tissue not presented by the image is of no concern.
Consistent with all of the descriptions of medical imaging devices is the concept of mapping the location of various tissue structures. The ability to map the images is critical because the device is not effective in practice if an abnormality is identified, but the physician does not know where it is within the patient's anatomy. Different portions of a three-dimensional object may be seen in different discreet images. The relative position of the slice is only known if the relative position of the patient to the imaging device is known when that image is obtained. Mapping can be as simple as identifying which limb was imaged by the X-ray, to acute, three-dimensional location of small structures in the complex structure of the complete anatomy.
It is not possible to “map” all of the structures a single two-dimensional view, however, because the human anatomy and human tissue structures are three dimensional. For example, if the X-ray reveals two shadows, or regions of interest, the device cannot determine which of two shadows is closest to the energy emitter and which is closer to the energy detector. A typical mammogram contains two images, each obtained by compressing the breast on planes that are not parallel, so that the location of the lesion can be determined through stereotactic calculations. Specifically, the location of a region of interest is typically described with regard to whether it is above or below the nipple, and whether it is medial or lateral to the nipple. For example, a lesion in the “upper-outer” quadrant is one that is located in the part of the breast which is nearest the shoulder and which presents lateral to the nipple (“outer”) on the cranio-caudad view and above the nipple (“upper”) on the medial-lateral-oblique view.
Another family of imaging devices maps the cellular tissue by taking more than one image on sequential parallel planes as a robotic element translates the imaging apparatus over the portion of the patient's anatomy which is to be studied. Each image is a slice, or cross-section of the region of cellular tissue that is to be imaged.
Computed Tomographic X-ray (CT) and Magnetic Resonance Imaging (MRI) image multiple “slices” or cross sections of the anatomy. Each slice, or frame, is a discreet image which describes all of the structures contained within that cross section, but do not describe information contained in adjacent slices. Computed Tomographic X-ray (CT) systems use a mechanism to move the X-ray source and detector over the entire body of the patient. Magnetic Resonance Imaging devices require the patient to lie, immobilized, in possibly in a prone position while he or she is literally moved, in totality, past the imaging structure. The rate of translation of that movement is controlled by a mechanical mechanism. Both of these devices use a form of robotics to control the translation of the imaging device to the patient, or the translation of the patient to the imaging device, so that each image may be mapped. The robotic control is designed to incorporate a real-time feedback mechanism to direct the path of the scanning and receiving mechanisms and direct the speed at which they scanning and receiving mechanisms translate. The goal of this real-time control is to assure that there is complete coverage (the path follows the directed course) and that the images are evenly spaced (to assure appropriate resolution). The primary purpose for controlling the speed is that most recording devices record at regular time intervals. A constant recording interval (e.g. frames/sec) divided by a constant translation speed (e.g. mm/sec) results in a regular spacing of images (e.g. frames/mm).
Unlike the robotic devices, the location of the manual imaging device is not controlled by an external mechanical structure when that device obtains the image. The device does not know where the imaging component is in space if the device does not know where the hand holding the device is in space. Therefore it does not know where the image is in space. One way that this problem has been addressed is to retrofit manual devices with location sensors that will provide spatial information of the images. For example, a manual scan to obtain regularly spaced images which cover the desired area is used to substitute the human operator for the robotic controls and use information from the location sensors to direct the human being, dynamically and in real time while he or she is scanning, to adjust the position, angle, and speed of the probe as it translates over the patient. If the user actually does respond to the prompts and adjusts his or her translational actions in real time, then the probe will translate over the skin at a constant speed and the images will be recorded at regular intervals. One drawback of this approach, however, is that there is no quality control to assure that the user responded to the prompts appropriately and that the images are actually being recorded at regular intervals. The situation is exacerbated if the program just assumes that the user made the adjustments and saves the images at the presumed locations and does not confirm actual spacing of the images. Another drawback of this approach is that it can be annoying to the operator to be prompted continually to adjust parameters on the scan. As such, there is a need for methods, devices, and systems that allow manual scanning without requiring that the operator scan the target area at a constant speed. Moreover, there is a need for systems and methods that interact with the operator to provide feedback either dynamically or non-dynamically during the scanning procedure that do not require the operator to alter scanning technique during the scan. Rather, the operator is provided feedback to repeat or rescan during the procedure but not necessarily during an actual scanning iteration.
Having the absolute mapping information of a discrete image is useful if that discrete image displays a particular region of interest. If the location of that particular region of interest is all that is required, then it is not necessary to know the relative position and orientation of each discrete image within the image set. If one wishes to reconstruct a three-dimensional map of a set of images, however, then the relative positioning information is critical. One discrete image may not be parallel to the orientation of the adjacent images or, for that matter, any of the images in the image set. The spacing between one discrete image and another may not be the same as the spacing between any other pair of discrete images within that image set. These disparities are of no consequence if the goal of the image procedure is merely to use the image information to map a region. One must merely determine the location of each pixel within all of the discrete images within the image set. These disparities are of consequence if one wishes to determine whether the quality of the map is adequate, in terms of coverage and resolution, as will be described later in this invention description.
Another factor to consider in the efficacy of any screening procedure is that of resolution, or the ability of the operator to resolve images of a desired size within the confines of the imaging technology. Most operators familiar with the art of image review are familiar with the concept of resolution when describing two-dimensional images, such as those presented on a television screen. For example, in the twentieth century standard television broadcasts presented images that were 704 by 480 pixels with a 4-to-3 aspect ratio (that is, the width of the screen is ⅓rd larger than the height), or sources of light, or pixels, displayed in an x-y grid. Each pixel is a single point which is uniform in color. If the television image was of a structure which was 70.4 cm by 48 cm is displayed on that 704 by 480 pixel screen, then each pixel describes a portion of that image which is 1 mm by 1 mm in size. Under these conditions, the ability of these images to distinguish, or “resolve”, smaller structures, such as a human hair (0.2 mm) is not possible. Zooming in on the image, as opposed to zooming in on the object with the camera, does not change the resolution. If one expanded one quarter of the screen to fit the size of the entire screen, then the entire screen would only contain 171 by 120 pixels of information. The display would be still be 704 by 480 pixels, but the expanded image would not contain more information and the single pixels of a single color that were in the smaller image would be presented as four adjacent pixels, each of the same color. In effect the individual small pixels would be replaced by larger “pixels”, but the resolution would not change by making that portion of the screen larger. Modern high definition (HD) Television presents images in a 1920 by 1080 pixel format. When one adjusts for changes in aspect ratios (16:9 instead of 4:3), the modern television image can resolve structures which are 2.5 times smaller than the 20th Century 704 by 480 pixel broadcast models. The modern high definition television could distinguish, or resolve, that human hair.
The ability to resolve smaller structures in the x-y presentation affects the operator's ability to interpret the two-dimensional image. Even when the resolution is sufficient to present small objects in some fashion, the operator may not be able to distinguish the exact nature of that small object unless the resolution can also present more details (that is smaller features) on the shape and texture of that object. Medical images typically have a broad range of resolution requirements and often those requirements are a function of the state of the technology. The earlier ultrasound devices packaged 64 imaging elements in a linear array and could not resolve features smaller than 2 mm. These devices found utility in a variety of medical imaging capacities. Modern ultrasound devices have 256 imaging elements and can easily resolve sub-millimeter features and the utility of the devices has expanded with the increased resolution capacity.
The level of resolution can vary along dimensional axes. For example, one manufacturer of a standard ultrasound system (the iU22, Philips Healthcare, Andover, Mass., USA), creates images from an ultrasound transducer with 256 active elements on an array which is 52 mm long. The system may be set to image variable depths of tissue. The design of the system allows it to produce more than one pixel per element and the image is displayed on a video monitor in a format which is 600 pixels by 400 pixels, with each pixel representing a unique tissue structure in the space of the plane of the image. Thus, an ultrasound image acquired from this system, with a depth setting of 5 cm, would have a resolution of 11.5 pixel/mm in the horizontal, or X axis and 8.0 pixel/mm in depth, or the Y axis. Changing the depth setting to 4 cm would change the Y pixel resolution of 10.0 pixel/mm (the X pixel density would remain unchanged).
In three-dimensional imaging, the translational resolution can differ greatly from the resolution presented in the planar presentation of each discrete image. Even if the resolution of the X-Y presentation of any one discrete image is sufficient to distinguish 1 mm structures, it is possible for a 1 mm structure to be missed entirely if the space, or “Z” vector, between the discrete images is greater than 1 mm. If one assumes a spherical region of interest and if the required Z-spacing vector spacing is a function of the X-Y resolution of the imaging device, then with most modern imaging devices, if the spacing between discrete images is less than ½ of the size of the minimum requirement for detection of regions of interest, then it is reasonable to assume that at least one discrete image will present a cross section of the lesion with a size which is large enough to be resolved on the X-Y presentation of that discrete image. By the way of example, if the operator desires to view a 1 mm region of interest, and spacing between discrete images is greater 0.5 mm, the smallest cross-sectional presentation of that 1 mm region of interest will be 0.86 mm. If the X-Y resolution of the images is smaller than 0.86 mm, as it is with most modern hand-held imaging devices (such as ultrasound), then the intra-image resolution is sufficient. The early CT devices had 8 discreet images. Although any single X-Y slice could resolve lesions as small as a millimeter, the inter-slice spacing made resolution of lesions smaller than 8.6 mm unreliable. Modern 64-slice CT devices have a 0.5 mm inter-slice spacing, making the ability to diagnose millimeter sized lesions possible.
As used herein, in some embodiments, the individual image slices are referred to as “discrete images” while the set of discrete images obtained in a single scan sequence are referred to as a “set of discrete images” or a “scan track”. Moreover, “scan” or “scan sequence” or “scan path” or “set of discrete images” are used in some embodiments to refer to a plurality of images recorded sequentially as the hand-held imaging probe is placed in contact with the patient and is moved from one location to another location on the patient.
A clear understanding of absolute and relative coordinate geometries is essential when mapping tissue images and determining resolution. Since the discrete images are typically presented in a two-dimensional format, whether on paper or on a video screen, mapping of that format is typically presented in a means compatible with the X and Y axes of a Cartesian coordinate system. For example, previously described Philips ultrasound device displays the images on a video monitor in a format which is 600 pixels by 400 pixels. Thus, an ultrasound image acquired from this system (which has a probe width of 5.2 cm), with a depth setting of 5 cm, would be 0.087 mm/pixel in the X axis and 0.125 mm/pixel in the Y axis.
A second image in the sequence would also represent a tissue slice that is 5.2 cm by 5 cm. The corresponding pixels are the pixels which are at the same X-Y coordinate in both images. The X-Y location of the first pixel of the first row of one image corresponds to the X-Y location of the first pixel of the first row of the second image; the X-Y location of the second pixel of the first row corresponds to the X-Y location of the second pixel of the first row, and so forth until the last X-Y location of the pixel of the last row of the first image, which corresponds to the X-Y location of the last pixel of the last row of the second image.
Hand-held imaging devices rely on a human operator to translate the imaging probe over the tissue to be examined and present resolution challenges that are very different from the robotic devices. The X-Y resolution of a single image may be comparable to another method. For example, the pixel spacing in modern ultrasound systems is 0.125 mm, approximately the same as a mammogram. The primary challenges in the efficacy of a hand-held device are the ability to map individual images, the ability to resolve between the discrete images in the image set, and to determine whether the family of image sets represents complete coverage of the structure.
As was described earlier, screening examinations require that the user image “all” of the tissue. Seeing “all” of the tissue is more a function of coverage than it is of resolution. Coverage, or field of view, is a description of the extent of the field of imaging, not the quality of the imaging. An X-ray of the kidney which images only half of the kidney may have finely detailed resolution, but it does not cover the entire kidney. Conversely, a blurry mammogram of the entire breast “covers” the entire breast, but may not do so with adequate resolution to be a useful examination.
As used herein, the term “coverage” is not intended to be limited to any particular meaning. The term broadly includes, at least, the distance, surface, volume, area, etc. that is imaged during a medical imaging session. For example, determining coverage of a scan would include evaluating whether there are any gaps in the relative positions of the images contained in (between) two or more scan track sets (e.g. scan-to-scan spacing or distance). As a comparison, resolution describes at least the X-Y and x-y-z resolution of each individual image and the relative spacing of the discrete images within a single scan track (e.g., image-to-image spacing or distance).
With an X-Ray or MRI or CT scan a single image, or slide, will tend to cover all of the tissue in a cross-section that can be 30 cm in size or larger. However, a typical ultrasound probe is 4 cm to 6 cm in size. It would require five or more parallel scan track sets of a 6 cm ultrasound probe to encompass the same volume of tissue that could be imaged with a single 30 cm mammogram.
Robotic devices have been used to previously achieve coverage because the desired field of view is predetermined and the systems are able to calculate the appropriate translational scan paths to encompass that field of view and they are programmed to translate the energy scanning and receiving elements along the predetermined paths. In contrast, manual imaging devices are operated based on the technical experience and subjective judgment of the human operator. The quality, particularly coverage, of the scanned recorded images varies widely depending on the operator. For example, if the operator scans too quickly, the images in a scan sequence may be spaced too far apart to show a potential cancerous region. Similarly, if the operator spaces two scan sequences too far apart, then there may be areas between scan rows that have not been scanned for review. As such, some embodiments described provide methods, devices, and systems for recording images to ensure that recorded images during a manual scanning session have adequate coverage.
As used herein, a “scan track,” in some embodiments, refers to any set of discrete images recorded by a medical imaging method, device, or system. The set of discrete images can be obtained by any method or device. In some cases the set of discrete images are obtained when an operator (1) places the probe on the patient, (2) begins recording images, (3) translates the probe across the surface of the skin, (4) stops recording the images. In other embodiments, a scan track is a set of sequential discrete images with unique relative spacing between individual discrete images. In such cases, the set of discrete images can encompass a volume which is as wide as the imaging probe design allows, as deep into the tissue as the imaging probe allows, and as long as may be accomplished by the act of recording the images while translating the probe across the skin.
Another difference between traditional mammography or the robotic devices and traditional hand-held imaging technologies is that mammography and the robotic devices depend on separating the imaging process in to two steps, (1) recording the image and (2) reviewing the image. With the hand-held devices the images can be presented in real-time, so the reviewer can dynamically review structures. When performing the procedure in real time, the skilled operator may believe that he or she is skilled in appropriately translating the probe to cover the breast entirely and to translate the probe with appropriate speed, and may believe that he or she does not need real-time feedback to achieve these goals. When the real-time images are recorded by one operator for later review by another, as is necessary to address the time constraints associated with screening, the reviewer does not have the ability to confirm the location of the image nor does he or she have the ability to confirm the spacing between adjacent images, if appropriate. The reviewer does not have the ability to determine the resolution in the “z” plane. Since the reviewer does not know the relative position of each scan track set of discrete images, the reviewer does not have a concept regarding whether this family of sets represents complete coverage.
For the purpose of this discussion, assume that X and Y axes of a Cartesian coordinate system are used to define a two-dimensional array of ultrasound scanning derived images containing a multiplicity of pixels, where the term pixel refers to the basic unit of a video screen image and can be defined by its X and Y coordinate value in any predetermined reference frame defining the location of zero for both the X and Y coordinates. These two-dimensional ultrasound images are generated by an ultrasound probe comprising a linear scanning array. A modern high-end scanning array consists of 256 transmitting and receiving transducers packaged in an ultrasound probe, said linear array of transducers having a width of 38 mm to 60 mm. These linear arrays of transducers produce images with the spacing between adjacent pixels ranging from 0.06 mm to 1 mm. Each individual pixel within the ultrasound-derived planar image is defined by a unique X and Y coordinate value. The two-dimensional resolution, or two-dimensional density of the pixels within each ultrasound scan-derived two-dimensional image (i.e., number of pixels per square centimeter of the image) is constant and is a function of the ultrasound system hardware and remains the same for each adjacent image in the scan process. This resolution allows routine identification of tissue abnormalities (e.g., cancers) as small as 1 mm to 5 mm.
The primary challenges in the three-dimensional reconstruction are the spacing between adjacent pixels in the third axis of the XYZ Cartesian coordinate system, viz., the Z-axis and the relative location of the families of sets of discrete images obtained during the scanning process.
The spacing along the Z-axis is dependent, in part, on the rate of change of the position and angle of the ultrasound probe between the creation of any two sequential and adjacent two-dimensional images. The change in the spacing between two sequential two-dimensional images depends on five factors:
One factor is the rate at which the ultrasound system hardware and software are capable of processing the reflected ultrasound signals and constructing the two-dimensional images (i.e., number of completed two-dimensional ultrasound scans per second).
The second factor is the rate at which the displayed images can be recorded, for example by a digital frame-grabber card. By way of example, if the ultrasound system displays 10 discrete images per second and a frame-grabber card can record 20 frames per second, then the recorded set of images will have 20 images but will, in reality, have only 10 discrete images with each image having a replicate. By way of another example, if the ultrasound system displays 40 frames per second and the frame grabber records 20 frames per second, the recorded set of images will have 20 discrete images, but will not have recorded an additional 20 discrete images.
A third factor is the rate at which the ultrasound probe is translated along the scanned path. By way of example, the faster the operator moves the ultrasound probe, the greater the spacing will be in the Z direction and/or the slower the combined rate at which the ultrasound system hardware and software are capable of processing the reflected ultrasound signals and constructing the two-dimensional images and the image recording hardware can store the processed images (i.e., the lower the rate of completed two-dimensional ultrasound scans recorded and stored per second), the greater the spacing will be in the Z direction. Conversely, if the operator moves the ultrasound probe more slowly, the smaller the spacing will be in the Z direction.
The fourth factor is the relative orientation of the hand-held probe during the scanning process. Because the probe is not held rigid by a mechanical mechanism, the translational distance between adjacent frames is not a constant. For example, if the discrete images within an image set were perfectly parallel, then the Z spacing between corresponding pixels would be the same for each pair of corresponding pixels in two discrete images. If the probe were rotated along the lateral axis (pivoted, or pitch) then the Z spacing of the corresponding pixels at the top of a pair of images would vary from the Z spacing of the corresponding pixels at the bottom of a pair of images. If the probe were rotated along its longitudinal axis (roll) then the Z spacing of corresponding pixels on the left side of the a pair of images would vary from the Z spacing of the corresponding pixels on the right side of the pair of images.
The fifth factor is associated with the rotation of the probe along its vertical axis (yaw). The distance between two corresponding pixels in a pair of images differs if the two images are recorded when rotation on the vertical axis differs.
In addition to determining the spacing between discrete images within a scan track set, it is important to understand the relative relationship between separate scan track sets within a family of scan track sets which describe a complete scan. This variable is an important factor in the function of coverage. If the images obtained within a single scan track adequately cover the tissue, then there is no need for a second scan track. If the single scan track is too small, in width or length, to cover the entire tissue structure, then a second scan track is needed. Since each scan track has its own set of discrete images, and since each discrete image has its own mapping location coordinates, it is possible to determine whether two separate scan tracks represent the exact same region of tissue, adjacent regions of tissue with some overlap, adjacent regions of tissue with no overlap, adjacent regions of tissue with some gap in between, or regions of tissue with no anatomic relation to each other.
The reconstruction of a plurality of scan tracks can describe a covered region if the scan tracks between any two adjacent scan tracks can be reconstructed to form a contiguous region of images with no gaps in coverage and if the extent of the reconstruction encompasses the entire tissue structure to be imaged.
As described earlier, prior techniques have relied on robotic machinery to calculate the number, the direction, and extent (length) of scan tracks required to have complete coverage and control the scanning variables ((1) image refresh rate, (2) image recording rate), (3) the translational speed of the probe, (4) the rotation of the probe along the lateral and longitudinal axes, and (5) and the rotation of the probe along the vertical axis) so that the resulting family of scan tracks contains images which have the coverage and resolution required for a “complete” examination of the tissue.
Robotic approaches to ultrasound imaging require the use of expensive mechanical equipment that is also subject to regular service and calibration to assure that the machine driven ultrasound probe is in the assumed position and computed orientation as required to assure that a complete and systematic diagnostic ultrasonic scan of the target living tissue has been actually achieved.
An objective of the present invention is to enable and assure the completeness of an ultrasound diagnostic scan of the target tissue (e.g., human breast), in terms of area covered and resolution of the relative spacing of the images within that area covered, without the need for robotic mechanical systems for the support, translation and computed orientation control of an ultrasound probe. Some embodiments enable the use of hand-held diagnostic ultrasound probe scanning methods while assuring that a complete scan of the targeted tissue is achieved.
As important as the imaging requirements are to achieving a practical screening technology, time constraints can also affect practicality, thus the utility, of the device. Berg et al., describe that the average time to perform a manual ultrasound screening examination of both breasts is 19 min and the median time is 20 minutes (Wendie A. Berg; Jeffrey D. Blume; Jean B. Cormack; et al., Mammography vs. Mammography Alone in Women at Combined Screening With Ultrasound and Elevated Risk of Breast Cancer, JAMA. 2008;299(18):2151-2163 (doi:10.1001/jama.299.18.2151). This time does not consider the time it takes the radiologist to walk from the reading room to the ultrasound examination room, the time it takes to interact with the patient, or the time it takes to return to the reading room from the ultrasound examination room.
The time required to view the actual images is much shorter. By the way of example, a standard screening ultrasound examination involves 2,000 to 5,000 images, obtained in a series of rows scanned according to one of many scan disciplines. If the recorded images are reconstructed and viewed as a cine, that is the sequential display of a set of discrete images, as in a movie, so that the viewing experience is the same as the operator would have experienced had he or she been performing the hand-held procedure in real time, then the review time could be as short as 200 seconds (less than 4 minutes). The concept of the cine presentation goes back more than a century, to Edison, but Freeland describes the use of the cine viewing technique for the review of ultrasound images in 1992 (U.S. Pat. No. 5,152,290).
It is standard practice for trained radiology technologists to perform the imaging function for most radiology procedures. The technologist's duties are to obtain good quality images and present them to the radiologist to interpret. In the way of an example, the average time required to obtain and record a standard 4-view mammogram is 10 min to 15 min, but the radiologist can interpret those images in less than two minutes.
As described earlier, although it is not possible for a skilled and trained operator to objectively determine the completeness of the area covered, and the resolution (in terms of the relative spacing between adjacent images) of a scan when they are personally performing a manual examination, they may believe, subjectively, that the coverage and resolution are adequate. If the reviewer is observing a set of images that were recorded by another operator, however, it is not possible for the reviewer to have any defendable means of determining whether the area covered represents the entire structure or that the resolution, in terms of spacing between images, meets the minimal standards that the user requires. Mapping the images and calculating the resolution and coverage of the resultant sets of images, as described in some embodiments herein, allows the ability to divide the imaging and reviewing tasks and, thus, allows the time savings associated with performing the procedure in a manner where it is recorded by one individual and reviewed by another and still provide some level of confidence as to the aforementioned resolution and coverage.
Mapping the images for resolution and coverage allows the cine review process to be speeded up as well. Speeding up the review reduces the requirements in the radiologist's time, providing utility to the operator. Standard cine review presents a series of discrete images in quick succession, but at a constant time interval (frames per second, or fps) with a dwell time for each frame a function of that time interval. By way of example, if the desired frame-to-frame resolution in an examination is 1 mm, and images are recorded at exact 1 mm intervals, and if the frames are reviewed at 10 fps, with a frame dwell time of 0.1 sec/frame, then the time to review a 10 cm scan track of discrete images (100 images) would be 10 seconds. If the images are recorded at exact 0.1 mm intervals (1,000 images) the review time would be 100 seconds. Although there is additional information in those 900 additional images, the incremental improvement in patient care may not be warranted for the additional 1.5 minutes of physician time to review the track. If one considers that there may be as many as 16 such scan tracks for each breast, then the time differential could be 320 seconds (just over six minutes) vs. 3,200 seconds (just over one hour).
Some embodiments described provide for systems and methods for providing a speeded review time by varying the dwell time between successive discrete images and calculating that dwell time as a function of the distance between adjacent images. The resultant presentation would be provided in distance covered per second (dcps) not frames per second. By way of example, if the system recorded 19 images, with the Z-plane location of those images being 0.0 mm, 0.7 mm, 0.9 mm, 1.9 mm, 2.5 mm, 2.8 mm, 3.6 mm, 3.7 mm, 4.0 mm, 4.7 mm, 5.1 mm, 5.6 mm, 6.6 mm, 7.0 mm, 7.6 mm, 8.2 mm, 8.5 mm, 9.5 mm, and 10.0 mm, then the review time for those 19 images at 10 fps (that is a dwell time of 0.1 sec/frame) would be 1.8 sec. If individual dwell times were assigned unique values with criteria based on amount of tissue to be imaged per second and the spacing between discrete images, then the review time could be shortened considerably. By way of example, if the dwell times of the 19 images described earlier were changed to 0.07 sec, 0.02 sec, 0.1 sec, 0.06 sec, 0.03 sec, 0.08 sec, 0.01 sec, 0.03 sec, 0.07 sec, 0.04 sec, 0.05 sec, 0.1 sec, 0.04 sec, 0.06 sec, 0.06 sec, 0.03 sec, 0.1 sec, and 0.05 sec, respectively, then the review time would be 1.00 seconds.
Some embodiments also provide for a means of speeding the review time by displaying only those images which provide incremental information that the operator deems useful. By way of example, if the user chooses an optimal resolution of 1.0 mm between images, and if there is more than one image in that 1.0 mm spacing, then the extra images are redundant. The system and method may choose to not display the redundant images. By further way of example with the images described in the previous paragraph, if the operator chooses an optimal image spacing of 1.0 mm, then the system would only display those images recorded at 0.0 mm, 0.9 mm, 1.9 mm, 2.8 mm, 3.7 mm. 4.7 mm, 5.6 mm, 6.6 mm, 7.6 mm, 8.5 mm, 9.5 mm and 10.0 mm. The images recorded at 0.7 mm, 2.5 mm, 3.7 mm, 4.0 mm, 5.1 mm, 7.0 mm, and 8.2 mm would be culled. If the retained images were displayed at 10 fps (a dwell time of 0.1 seconds/frame) then the image review time would be 1.1 seconds, not the 1.8 seconds that would be required if all of the images were reviewed.
Another system and method for milking the review time required by the radiologist would be to cull images whose information is contained completely within another set of discrete images. By way of example, if the operator is reviewing a scan of the breast which contains 12 sets of discrete images, each image originating at the nipple and extending radially to the base of the breast at each of the 12 clock positions, there will be images within some of those sets of discrete scans that image tissue structures that overlap or are partially or completely imaged by other images or groups of images. By way of example, if because the radius of coverage decreases as the scans get closer to the nipple, the 5 mm probe extends from 10 o'clock to 2 o'clock when the probe is performing the 12 o'clock scan is only 1 cm from the nipple, and the probe extends from 1 o'clock to 5 o'clock when the probe performing the 3 o'clock scan is just 5 mm from the nipple, then there is a substantial and possibly complete overlap between these two scans and the images recorded by the 1 o'clock scan at 5 mm from the nipple and the 2 o'clock scan at 5 mm from the nipple contain redundant information. If those images were removed from the review set then the result would be a time savings. This system and method teaches a means of distinguishing which images contain information that is completely or partially contained in one or more images from other sets of discrete images in the scan and removing those images from the review set. Overlap of information in images could be anywhere from about 10% to about 100%. In some embodiments, images with information having 80%-100% overlap with other images are removed from the review image set.
Some embodiments described provide for methods, apparatus and systems for determining the resolution or spacing of the image-to-image spacing of discrete images within sets of discrete images, or scan sequences, and determining the coverage of multiple sets of discrete images, or scan sequences, in a hand-held imaging scan of targeted human tissue such as the human breast. In one embodiment, the range of the image-to-image resolution within each scan sequence is about 0.01 mm to 10.0 mm. In another embodiment, the image-to-image resolution within each scan sequence is about 0.1 mm to 0.4 mm. In further embodiments, the image-to-image resolution within each scan sequence is about 0.5 mm to 2.0 mm.
In another embodiment, the range of the image-to-image resolution within each scan sequence is a pixel density between 9,000 and 180,000,000 pixels/cm3. In other embodiments, the pixel density is between 22,500 and 18,000,000 pixels/cm3. In further embodiments, the pixel density is between 45,000 and 3,550,000 pixels/cm3.
In some embodiments, the range of coverage, in terms of the overlap of the border of adjacent scan tracks is between about −50.0 mm to +50.0 mm (where a negative overlap value indicates a positive gap value, or spacing between the borders of adjacent scan tracks). In other embodiments, the overlap of the border of adjacent scan tracks is between about −25.0 mm to +25.0 mm (where a negative overlap value indicates a positive gap value, or spacing between the borders of adjacent scan tracks). In further embodiments, the overlap of the border of adjacent scan tracks is about −10.0 mm to +10.0 mm (where a negative overlap value indicates a positive gap value, or spacing between the borders of adjacent scan tracks).
Examples of hand-held imaging procedures include, but are not restricted to, ultrasound examinations. Objective determination that user-defined levels of coverage and resolution are achieved is critical, particularly when one clinical practitioner performs the recording function during the hand-held scan and another practitioner, who was not present at the recording procedure, reviews those pre-recorded images. Objective determination of coverage and image-to-image resolution or spacing that the subsequent review of the recorded images by a trained clinical specialist following the scanning procedure is critical to assure that the subsequent review does not result in a false negative assessment due to the fact that some regions of the targeted tissue volume were inadvertently omitted. Such omissions can be caused by the inadvertent excessive spacing between successive hand-held scans that are intended to cover the tissue structure, excessive image-to-image spacing within a single hand-held scan that can result from variations in rate of translation of the hand-held imaging probe and/or the excessive rate of change of the orientation of a hand-held imaging probe during the scanning of a targeted tissue volume such as the human breast.
The tracking of the position and computed orientation of a hand-held imaging probe can be accomplished by affixing position sensors on the body of the ultrasound probe at predetermined locations relative to the design geometry of the hand-held imaging probe imaging elements. Three or more sensors are affixed to the hand-held imaging probe to enable the computation of the position (viz., x, y, z coordinates) of the hand-held imaging probe imaging elements and the computation of the orientation of the longitudinal axis of the hand-held imaging probe body. Said orientation coincides with the axis of image, for example the planar ultrasound beam emitted into the tissue being interrogated.
According to some embodiments, the accurate and dynamic computation of the position of the hand-held imaging probe's imaging elements enables the determination of the actual spatial position and computed orientation of manually scanned, sequential pathways completed along the tissue surface. The computed position and computed orientation of each manually scanned, sequential pathway, combined with information regarding the dimensional size of each recorded image, along the tissue surface enables the further computation of the physical spacing or distance between scan sequences. This computation can be rapidly completed during the course of the manual scanning process or procedure and a visual and optional audible cue as well as an image is provided showing the paths of completed scan sequences to identify where re-scanning is required. This intra-procedure computation of the distances between adjacent scan sequences determines whether complete coverage of the targeted tissue volume is achieved with the hand-held imaging probe. Accordingly, this intra-procedure computation of the distances between adjacent scan sequences assures that the completed scan sequences cover the targeted tissue structure by assuring that the individual scan sequences overlap, or are separated by an acceptable distance.
In addition, according to the teachings of this invention, the accurate and dynamic computation of the position of the hand-held imaging probe's imaging elements enables the determination of the actual spatial position and computed orientation of each image within the sequential and manually scanned pathways completed along the tissue surface of the targeted defined volume of tissue. The physical spacing between discrete images in scanned pathways can be determined by using the computed position and computed orientation of each manually scanned, sequential pathway with information regarding the dimensional size of each recorded image. This computation can be rapidly completed during the course of the manual scanning process and a visual and optional audible cue as well as an image is provided showing the paths of completed scan sequences to identify where re-scanning is required. This intra-procedure computation of the distances between adjacent scan sequences determines whether image-to-image resolution of the targeted tissue region is achieved with the hand-held imaging probe is achieved by identifying distances between completed discrete scan images that are inadvertently separated by an unacceptably large distance.
In addition, according to some embodiments, the accurate and dynamic computation of the orientation (based on the positions of the three or more sensors) of the hand-held imaging probe's longitudinal axis (hence, the orientation of its emitted planar imaging beam) enables the computation of image-to-image resolution or spacing by enabling the computation of a chord length between the planar images at the maximum depth of tissue being scanned for any two successive time steps at which images are obtained and recorded during any manual scan sequence along the tissue surface. The computed rate of change of orientation of the hand-held imaging probe (derived from position sensors affixed to the hand-held imaging device) during a manual scan sequence along the tissue surface enables the further computation of the physical spacing (i.e., chord length) between planar ultrasound scans between two successive time steps during a scan sequence. This intra-procedure computation of the chord distances between hand-held imaging planar scans acquired and recorded for any two consecutive time steps assures that a complete hand-held imaging scan of the targeted tissue region is achieved in terms of image-to-image resolution or spacing. This is accomplished through position change computations, thereby identifying any completed scan sequence in which the chord distances, at the maximum depth of interrogation, between adjacent discrete images are unacceptably large.
In addition, according to some embodiments, the accurate and dynamic computation of the orientation (based on the positions of the three or more sensors) of the hand-held imaging probe's lateral axis (hence, the orientation of its emitted planar imaging beam) enables the computation of image-to-image resolution by enabling the computation of a chord length between the sides of two planar images, from the surface of the tissue to the maximum depth of tissue being scanned for any two successive time steps at which images are obtained and recorded during any manual scan sequence along the tissue surface. The computed rate of change of orientation of the hand-held imaging probe (derived from position sensors affixed to the hand-held imaging device) during a manual scan sequence along the tissue surface enables the further computation of the physical spacing (i.e., chord length) between planar ultrasound scans between two successive time steps during a scan sequence. This intra-procedure computation of the chord distances between hand-held imaging planar scans acquired and recorded for any two consecutive time steps assures that a complete hand-held imaging scan of the targeted tissue region is achieved in terms of image-to-image resolution. This is accomplished through position change computations, thereby identifying any completed scan sequence in which the chord distances, at the maximum depth of interrogation, between adjacent discrete images are unacceptably large.
An alternative method for assuring the completeness of any individual scan sequence, in terms image-to-image resolution/spacing, (e.g., any individual path scanned beginning at the nipple of the breast and ending at the chest surface beyond the perimeter of the breast boundary) involves computation of the pixel density in each unit volume within the swept volume of the scan sequence. In the case of an ultrasound examination of the breast, the swept volume of the scan sequence would be the volume defined by (a) the width of the ultrasound beam, which is defined by the length of the ultrasound transducer array (e.g., 5 cm), (b) the depth of recorded penetration of the ultrasound beam into the targeted living tissue (e.g., 5 cm) and (c) the total length traversed in the individual scan sequence (e.g., 15 cm). This total volume (375 cubic cm in the present example is then subdivided into unit volumes (e.g., cubical volume of dimensions 1.0 cm×1.0 cm×1.0 cm). For this example, the swept volume would be subdivided in to 375 unit volumes. The number of ultrasound pixels within that unit volume would be the total number of pixels in the portion of each discrete ultrasound image which is defined as being within the three-dimensional boundaries of the unit volume. The number of ultrasound scan pixels contained in each unit volume is computed and this number is compared to a predetermined Minimum Pixel Density number. If the computed pixel density within any unit volume (i.e., any of the 375 unit volumes in this example) within the swept volume is less than the Minimum Pixel Density, then the operator is alerted at the end of the scan sequence that scan sequence just completed is incomplete and that it must be repeated including a display of instructions to improve scanning method (e.g., reduce scanning speed and/or rate of change of orientation of hand-held ultrasound probe during the repeated scan sequence).
In addition to affixing spatially arranged position sensors on a hand-held and manually applied imaging probe, another embodiment also provides a receiving device to detect and digitally record and store a digitized set of numbers which indicate the position and computed orientation of the hand-held imaging probe as well as the time associated with said position and computed orientation at each time step (i.e., time-stamped position and computed orientation data). Also, a digital data storage device provides for the recording of hand-held imaging image data at multiple times per second, images which are also time stamped for purposes of subsequent review by an individual or software capable of expert analysis of hand-held imaging images to detect the presence of suspicious lesions within the targeted tissue volume.
Once the completeness of the hand-held imaging scan has been confirmed (and scan sequences repeated if any regions within the targeted tissue volume were not scanned), the complete set of consecutive hand-held imaging images can be reviewed by play back of the recorded images at regular time steps (e.g., 6 to 12 frames per second).
According to one aspect of the present invention there is provided an imaging system for acquiring a sequence of two-dimensional images of a target volume represented by an array of pixels I (x,y,z) comprising [a] a hand-held imaging probe to scan said target volume along a path, which may be predetermined or may be determined dynamically as the operator performs the procedure, and generate a sequence of digitized two-dimensional images thereof representing cross-sections of said target volume on a plurality of planes spaced along said scanning path; said scanning path may any geometric path determined by the scanning personnel and is not required to be linear; [b] a data storage medium for storage of digital data associated with each pixel of each two dimensional image in a sequence of digitized two-dimensional images together with other related image data defining the location of said two-dimensional images in said memory and defining interpretation information relating to the relative position of pixels within said two-dimensional images and to the relative position of pixels in adjacent two-dimensional images within said target volume; and [c] software algorithm to determine if the relative position of pixels in adjacent two-dimensional images within said target volume exceeds a predetermined limit.
According to another aspect of the present invention there is provided an imaging system for acquiring two or more sequences of two-dimensional images of a target volume represented by an array of pixels I (x,y,z) comprising [a] a hand-held imaging probe to scan said target volume along two or more scanning paths, which may be predetermined or may be determined dynamically as the operator performs the procedure, and generate two or more sequences of digitized two-dimensional images thereof representing cross-sections of said target volume on a plurality of planes spaced along said scanning path; said scanning paths may any geometric path determined by the scanning personnel and is not required to be linear; [b] a data storage medium for storage of digital data associated with said sequences of digitized two-dimensional images together with other related image data defining the location of said two-dimensional images in said data storage medium and spatial and temporal information relating to the relative position of pixels at the edge of said two-dimensional images and to the relative position of pixels in one or more adjacent two-dimensional images at the edge of the adjacent scan sequence; and [c] software algorithm to determine if the relative position of pixels in adjacent two-dimensional images within said target volume exceeds a predetermined limit.
According to yet another aspect of the present invention there is provided an imaging system for acquiring two or more sequences of two-dimensional images of a target volume represented by an array of pixels I (x,y,z): [a] a hand-held imaging probe to scan said target volume along two or more scanning paths, which may be predetermined or may be determined dynamically as the operator performs the procedure, and generate two or more sequences of digitized two-dimensional images thereof representing cross-sections of said target volume on a plurality of planes spaced along said scanning path; said scanning paths may any geometric path determined by the scanning personnel and is not required to be linear; [b] a data storage medium for storage of digital data associated with each pixel of said sequences of digitized two-dimensional images together with other related image data defining the location of said two-dimensional images in said data storage medium and constructing a three-dimensional array of said pixel locations; and [c] software algorithm to determine if the pixel density within a predetermined volume is greater than a predetermined limit.
Another embodiment of the present invention incorporates methods, apparatus and system for optical recognition (e.g., using infrared wavelength detection of unique markers affixed to hand-held imaging probe assembly) to continuously detect the position and orientation of a hand-held ultrasound probe assembly in place of the use of electromagnetic radiofrequency position sensors. In some embodiments, an optical recognition based position and orientation detection method, apparatus and system accurately determines the position of each two-dimensional ultrasound scan image and, thereby, the temporal and spatial position of each pixel within each two-dimensional ultrasound scan image.
Another embodiment of the present invention incorporates methods, apparatus, and system for optimizing image review time on the part of the physician. The recorded images are reviewed as a series of still images, those images being presented for a fixed period of time (e.g. 0.1 sec each). The more images there are to review, the longer the review time for the physician will be. Since optimizing (that is, reducing) review time is an important aspect of any image review procedure, care must be taken that the review is thorough, but not excessive. Since the images will be recorded with a hand-held probe, it is possible that the relative spacing of adjacent images will vary. Some images may be spaced so closely that they are, in effect, redundant, while others may be spaced so far apart that it is possible to miss important structures. The prior part of this application describes methods for dealing with the latter scenario. Some embodiments described will optimize physician review time by one of two methods:
1. The system will choose an optimal image spacing parameter and a maximum allowable image spacing parameter. The maximum spacing between relative images will be calculated and the images for which the relative spacing is closest to the optimal spacing parameter shall be saved, and intermediate images shall be culled. For example, if the operator varies his or her scan so that images are recorded at 0.0 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.8 mm, 3.0 mm, 3.2 mm, 3.5 mm, 3.7 mm, 4.0 mm, 4.3 mm, 4.7 mm, 5.0 mm, 5.5 mm, and 6.0 mm, and the review time is 0.1 sec per image, the time to review these images is 1.5 seconds. If the operator decides that the optimal spacing to detect small lesions is 1.0 mm, then those images that were recorded at 1.5 mm, 2.8 mm, 3.2 mm, 3.5 mm, 3.7 mm, 4.3 mm, 4.7 mm, and 5.5 mm are not necessary to find the small lesions. They are redundant and add 0.8 seconds to the review time. Image review time could be halved, from 1.5 seconds to 0.7 seconds, by culling these images (
2. The system will vary its playback time based on the spacing of the images. Computers and computer display systems make it relatively simple to vary the dwell time for displayed images when replaying them. In the example cited above the first image (0.0 mm) could be displayed for 0.1 seconds while the four subsequent images (1.0 mm, 1.5 mm, 2.0 mm, and 2.8 mm) could be displayed for 0.05 seconds, and the time to review images covering the region would be 0.3 seconds. If, in this example, the dwell times for the images recorded at 3.2 mm, 3.5 mm, 3.7 mm, 4.0 mm was 0.025 seconds and the dwell time for the images recorded at 4.3 mm, 4.7 mm and 5.0 mm, was 0.033333 seconds, and the dwell time for the images recorded at 5.5 mm and 6.0 mm was 0.05 seconds, then the total review time from 0.0 mm to 0.6 mm would be 0.7 seconds, the same as if the redundant images had been culled.
In some embodiments, the tissue structure to be examined is the human torso. In other embodiments, the tissue structure to be examined is the human breast. In further embodiments, the tissue structure to be examined is the female human breast.
Some embodiments provide for a scanning completeness system for screening a defined volume of tissue having a manual image scanning device including an imaging probe, a system comprising three or more position sensors coupled with the image scanning device, a receiver to receive a set of discrete images from the image scanning device, a receiver to receive position data from locating system comprising three or more position sensors for each image in said set of discrete images, an image position tracking algorithm to determine the relative resolution of that set of discrete images of tissue within said defined volume, and a position tracking algorithm to determine the relative coverage of that set of discrete images of tissue, relative to another set of discrete images of tissue within that said defined volume. In further embodiments, the manual image scanning device is an ultrasound scanning device and the imaging probe is an ultrasound probe. In other embodiments, the manual image scanning device is an imaging device which utilizes ultrasound-derived properties including, but not restricted to, color Doppler and elastography.
In other embodiments, the position sensor can be a device which emits a magnetic or electromagnetic signal and locating system can include a device for sensing the relative position of the source of that magnetic or electromagnetic signal. In further embodiments, the position sensor can be a register which reflects electromagnetic radiation in the visible spectrum, or wavelengths between 750 nm and 390 nm, which may be detected by an optical camera and locating system can mean three or more optical cameras which can record the relative position between the register and the camera.
In another embodiment, the position sensor can be a register which reflects electromagnetic radiation in the infrared spectrum, or wavelengths between 100,000 nm and 750 nm, which may be detected by an infrared camera and locating system can include three or more infrared cameras which can record the relative position between the register and the camera. In a further embodiment, the position sensor can be a register which reflects electromagnetic radiation in the ultraviolet spectrum, or wavelengths between 390 nm and 10 nm, which may be detected by an ultraviolet camera and locating system can mean three or more ultraviolet cameras which can record the relative position between the register and the camera.
In some embodiments, the system comprises a storage device to store the discrete image data. In another embodiment, the system comprises a storage device to store the position sensor data corresponding to each discrete image. Further embodiments include a viewer to display the discrete images, wherein the viewer can provide a sequential display of said discrete images.
In some embodiments, the relative image resolution algorithm measures the three dimensional spacing between a pixel in one discrete image and a pixel at the same location of a second image recorded in a sequentially acquired image set. In other embodiments, an audible signal is issued in the event that the image resolution is not within a user-defined limit. In further embodiments, a visual signal is issued in the event that the image resolution is not within user-defined limits. In some embodiments, the visual signal identifies discrete image sequence wherein that the image resolution is not within user-defined limits.
In further embodiments, the image resolution algorithm creates a set of discrete image subsets by superimposing a three-dimensional volumetric boundary on adjacent images, determining which images have discrete image subsets which are described within that boundary, segregating the portions of each image subset which is described within that boundary, and calculating the pixels within the described subset of image portions.
In some embodiments, an image coverage algorithm measures the three-dimensional spatial distance the three dimensional locations of the edge boundaries of one set of sequentially-recorded images with a second set of sequentially-recorded images.
Other embodiments provide for a method for screening a defined volume of tissue with an image scanning device, comprising the following steps: scanning tissue within defined volume using a manual imaging probe; detecting the position of the imaging probe using three or more position sensors coupled with the imaging probe; receiving a set of discrete images from the image scanning device; receiving position data from locating system comprising three or more position sensors for each image in said set of discrete images; application of position tracking algorithm to determine the resolution of that set of discrete images of tissue within said defined volume; and application of position tracking algorithm to determine the relative coverage of that set of discrete images of tissue, relative to another set of discrete images of tissue within that said defined volume. In some embodiments, the manual image scanning device is an ultrasound scanning device and the imaging probe is an ultrasound probe. In some embodiments, a viewer is used to display discrete images, providing a, sequential display of said discrete images.
Some embodiments include one or more microprocessors to calculate the image resolution by calculating the three dimensional spacing between a pixel in one discrete image and a pixel at the same location of a second image recorded in a sequentially acquired image set.
Some embodiments provide for using one or more microprocessors to create a set of discrete image subsets by superimposing a three-dimensional volumetric boundary on adjacent images, determining which images have discrete image subsets which are described within that boundary, segregating the portions of each image subset which is described within that boundary, and calculating the pixels within the described subset of image portions.
In some embodiments, a locating system issues one or more audible signals in the event that the image resolution is not within user-defined limits to alert operator to obtain additional discrete images. In some embodiments, the locating system issues one or more visual signals in the event that the image resolution is not within user-defined limits to alert operator to obtain additional discrete images. In further embodiments, the visual signal identifies discrete image sequence wherein that the image resolution is not within user-defined limits to direct operator to location within defined volume requiring one or more additional discrete images.
In some embodiments, one or more microprocessors measure the three-dimensional spatial distance of the three dimensional locations of the edge boundaries of one set of sequentially-recorded images with a second set of sequentially-recorded images.
Some embodiments describe a method of displaying sequential images of tissue, wherein each image having assigned spatial coordinates, a discrete image display algorithm calculates the relative spacing between discrete images and modifies the rate of display of recorded discrete images to provide a uniform spatial-temporal display interval between successive discrete images. Other embodiments describe a method of displaying sequential images of tissue, wherein each image having assigned spatial coordinates, a discrete image display algorithm is used to determine whether a plurality of images are described within a user-defined interval for image spacing. Further embodiments provide that one or more of the plurality of images described within a user-defined interval for image spacing is not displayed as part of the set of discrete images.
Additional embodiments describe a method of displaying multiple sets of sequential images of tissue, wherein each image having assigned spatial coordinates, a discrete image display algorithm is used to not display one or more discrete images when the plane of that discrete images falls within a boundary of one or more sets of other sequential images.
Other objects of the invention will be obvious and will, in part, appear hereinafter. The invention, accordingly, comprises the method, system and apparatus possessing the construction, combination of elements, arrangement of parts and steps, which are exemplified in the following detailed description. For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings.
The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
As described briefly above, embodiments contemplated provide for methods, devices, systems that can be used with manual imaging techniques to ensure satisfactory quality and adequate completeness of a scanning procedure for a patient's target region. Some embodiments employ rapid-response position sensors or rapidly imaged optical registers affixed to an existing hand-held imaging system, for example, a diagnostic ultrasound system, and associated hand-held imaging probes. By way of example, one type of ultrasound system that can be used with some embodiments described is the Phillips iU22 xMatrix Ultrasound System with hand-held L12-50 mm Broadband Linear Array Transducer (Andover, Mass.). Also, a commercially available system which provides accurate x, y, z position coordinates for multiple sensors as a function of time, providing said position information at a rapid tracking rate, is, by way of example, the Ascension Technology 3D Guidance trakSTAR (Burlington, Vt.).
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Another embodiment is further illustrated in an exploded view of the hand-held probe assembly 30 as seen in
Additional features of first support member 42 are revealed in
Returning to
Accordingly, as specified in the previous paragraph, the first and second support members 42 and 44 are sized to correspond to the particular contour and dimensions of a specific hand-held ultrasonic probe design. For the case of injection-molded plastic, e.g., a biocompatible grade of polycarbonate, the inner dimensions of said first and second support members 42 and 44 are designed to closely match the outer dimensions of the hand-held ultrasound probe 14. The wall thickness, t1 (see
An example of the use of described embodiments is seen in
By way of example, the hand-held ultrasound probe assembly 30 is moved by the operator using a manual technique along the pathway illustrated in
An important aspect of the present invention is illustrated in
In some embodiments, measuring or calculating the spacing or distance between individual images in a scan sequence may be referred to as determining the image-to-image resolution or spacing between discrete images in a scan sequence. Alternatively, frame to frame resolution may also be used to describe the spacing/distance between images in a scan sequence.
By way of example and referring first to
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One embodiment for calculating the completeness of the scan sequence in terms of frame-to-frame resolution is to calculate the maximum distance between any two adjacent image frames. Since the concept of minimum acceptable resolution, by definition, requires the establishment of a maximum acceptable spacing, then that resolution requirement will be met if the largest distance 716 between any two corresponding pixels 94 in adjacent image frames is within the acceptable limit. Since the frames are planar, then the largest distance between any two frames will occur at the corresponding pixels 94 that are at one of the four corners. Thus, the maximum distance 716 between any two corresponding frames shall be (EQ. 1):
{Maximum Distance between any Two Corresponding Frames}==MAX(DISTANCE(P(FIRST-ROW, FIRST-COLUMN)−P′(FIRST-ROW, FIRST-COLUMN)), DISTANCE(P(FIRST-ROW, LAST-COLUMN)−P′(FIRST-ROW, LAST-COLUMN)), DISTANCE(P(LAST-ROW, FIRST-COLUMN)−P′(LAST-ROW, FIRST-COLUMN)), DISTANCE(P(LAST-ROW, LAST-COLUMN)−P′(LAST-ROW, LAST-COLUMN)))
Exemplary distances are shown in
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In some embodiments, the range of the image-to-image resolution (spacing) within each scan sequence is a pixel density between 9,000 and 180,000,000 pixels/cm3. In other embodiments, the pixel density is between 22,500 and 18,000,000 pixels/cm3. In further embodiments, the pixel density is between 45,000 and 3,550,000 pixels/cm3.
An equally important aspect of the present invention is illustrated in
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In some embodiments, measuring or calculating the spacing or distance between scan sequences may be referred to as determining the scan-to-scan spacing between scan sequences. Scan-to-scan spacing is a method of measuring, calculating, or otherwise determining coverage. If the images in the scan sequences overlap, there is coverage. If there is a gap between the two scan sequences, there is incomplete coverage.
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Once the position sensing detection and recording function has been activated, as represented by arrow 3126 to block 3128, the operator now proceeds to translate the hand-held imaging probe along the skin to begin the first of [i] scan sequences, SS[i,t] where i equals the number of scan sequences to be performed and t refers to the time period at which an ultrasound beam is emitted into the tissue and a returning acoustic signals are measured and recorded in what is referred to herein as an ultrasound scan “frame”. For the case of the first scan sequence (e.g., see scan sequence 80a in
Once the first scan sequence (i=1) is completed, as represented by arrow 3130 to block 3132, the operator releases the foot pedal to pause (i.e., to temporarily deactivate) the image recording function of the data acquisition and display module/controller. The time-stamped hand-held imaging probe position and computed orientation data acquired within the data acquisition and display module/controller is combined with the time-stamped ultrasound scan frames received from the ultrasound system to enable rapid computation of the image-to-image resolution of the scan sequence just completed. As represented by arrow 3134 to block 3136 as seen in
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Throughout the hand-held imaging procedure, the progression of scan sequences is shown on the screen of display 3 of the data acquisition and display module/controller 40 with the sequential scan index, i identified adjacent to each completed scan sequence in a manner similar to the illustration in
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In addition to mapping the three-dimensional position of the pixels recorded from a set of two-dimensional images, the method, apparatus and system of some described embodiments performs a pixel density calculation to provide an objective characterization of the resultant image set to determine whether that spacing in the Z direction is sufficient to provide an accurate and complete three-dimensional image of the targeted tissue volume (e.g., the human female breast). By way of example, each of the pixels in each ultrasound scan-derived two-dimensional image, i are specified by a unique set of coordinates X{i,j} and Y{i,j} in two-dimensional space. When two adjacent two-dimensional images i and i+1 are combined to form a three-dimensional volume, then the position of each pixel is transformed into three-dimensional space and can be defined by the three Cartesian coordinates Xij, Yij and Zij.
Continuing with this example and referring to
Coordinates of Square Side Faces on ith two-dimensional image 2200:
Coordinates of Square Side Faces on (i+1)th two-dimensional image 2201:
Continuing with this example, the maximum spacing between the square 2 mm×2 mm faces on adjacent two-dimensional images 2200 and 2201 for the first component volume is determined by comparing the following four distances along the Z axis:
For this example, assume that the maximum distance between the four corners of the squares 2210 and 2211 in
First Component Volume=A*{Z14-Z24} EQ. 2
Continuing with this example and still referring to
First Component Volume Pixel Density=(Total No. of Pixels in both Unit Areas)÷(First Component Volume) EQ. 3
Referring now to
Another embodiment of the present invention utilizes the geometrical relationship of any two sequential ultrasound scan images to reduce the number of component volumes that need to be analyzed to determine if [a] the maximum spacing limit between sequential ultrasound scan images has been exceeded and/or [b] the minimum pixel density in a component volume has not been achieved. Referring now to the example in
Each two-dimensional ultrasound scan image, e.g., scan images 2200 and 2201, can be assumed to take the geometric form of a flat planar surface. In addition, since any two sequential two-dimensional ultrasound scan images are acquired within a very short time period, the boundary of the ith two-dimensional scan image (e.g., scan image 2200) is registered with and can be projected onto the boundary of the (i+1)th two-dimensional scan image (e.g., scan image 2201). As a result of the registration of the boundaries of any two sequential two-dimensional ultrasound scan images and their planar geometry, only those component volumes located at the four “corners” of the pair of sequential two-dimensional ultrasound scan images, as seen in
By way of example and still referring to
By this novel method, the described embodiments greatly reduces the computation time required to assure that each subsequent two-dimensional ultrasound scan image meets the requirements for maximum allowed spacing and/or minimum required pixel density and that the operator can be alerted immediately after each scan path has been completed.
When the two-dimensional ultrasound scan-derived images are being presented in sequence, the greater the spacing between sequential scans (i.e., along the Z-axis as seen in
Minimizing the time duration of the reviewing process while maximizing the ability to recognize abnormalities within the video presentation of the ultrasound screening results is of primary importance to the clinician to avoid fatigue and maximize the efficient use of the clinician's time. The ultrasound scanning-derived image recording is time-based, with the images obtained in a temporally uniform manner. This approach can present several problems. First, if the image spacing varies from one part of the scan to the next, then the ability to present the images in a spatially uniform manner is compromised. One portion may have images spaced on 0.01 mm centers while another may have them spaced on 1 mm centers. If the information recorded during the portion where images were recorded at 0.01 mm centers will take 10 times longer to display the same subset of swept volume of scan sequence as does the portion where images were recorded on 0.1 mm centers. When seeking to detect abnormalities on the order of 5 mm, it can be argued that there is no more real information presented in the 0.01 mm-center scans than there is in the 0.1 mm-center scans. The portion with the more closely spaced images may represent a reduction in viewer efficiency, not an increase in procedure efficacy.
Another embodiment of the present invention is seen in
Another embodiment of this present invention, also seen in
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Some embodiments described provide for the control of the imaging recording process by taking into consideration several factors during the scanning process. For example, these factors include image-to-image spacing, angular position of the probe, and scan-to-scan spacing. This allows the images to be recorded with uneven or non-constant spacing between one or more images. Uneven or non-constant spacing is often the result of variable translation speed as the operator moves the probe across a target region. Variable speed creates images of varying distances from one another. Some embodiments allow the operator to vary the speed of scanning while still ensuring adequate resolution and coverage of the scanned images. This can be accomplished by maintaining a minimum image-to-image distance, minimum scan-to-scan distance, or minimum pixel density.
As a further example, if the user varies his or her translational speed during a process so that the plurality of recorded images 400a-400o (see
If the user varies his or her translational speed during a process so that the plurality of recorded images 400a-400o, each having its own unique location identifier information, are spaced unevenly, the system and method can reduce the review time by calculating how long each of those images should be displayed during the review process, and which, because they are so closely spaced to the previous or following image, should not be displayed. By way of example, if the user wishes to review the 6 mm of tissue described in
Other embodiments described provide for systems and methods for providing a speeded review time by limiting the number of images recorded. If an operator varies his or her speed during the scan process and the images are recorded at regular time intervals, then the recorded images will have irregular spacing. It is not necessary, however, that the system records the images at regular time intervals. The system may determine when to record the image by calculating where the image is in space, rather than as a function of time. By way of example, if the system recorded 19 images in one second, with the Z-plane location of those images being 0.0 mm recorded at 0.0 sec, 0.7 mm recorded at 0.1 sec, 0.9 mm recorded at 0.2 sec, 1.9 mm recorded at 0.3 sec, 2.5 mm recorded at 0.4 sec, 2.8 mm recorded at 0.5 sec, 3.6 mm recorded at 0.6 sec, 3.7 mm recorded at 0.7 sec, 4.0 mm recorded at 0.8 sec, 4.7 mm recorded at 0.9 sec, 5.1 mm recorded at 1.0 sec, 5.6 mm recorded at 1.1 sec, 6.6 mm recorded at 1.2 sec, 7.0 mm recorded at 1.3 sec, 7.6 mm recorded at 1.4 sec, 8.2 mm recorded at 1.5 sec, 8.5 mm recorded at 1.6 sec, 9.5 mm recorded at 1.7 sec, and 10.0 mm recorded at 1.8 sec, then the time to record those 19 images is 1.8 sec and the time to review them would be 1.8 sec at 10 frames per second. If the system only recorded images when they were at the desired spacing, then the review time and the image storage requirements would be lessened. By way of the above example, the probe is at 0.0 mm at 0.0 sec, it is at 1.0 mm at approximately 0.21 sec, it is at 2.0 mm at approximately 0.3167 sec, it is at 3.0 mm at approximately 0.5125 sec, it is at 4.0 mm at 0.8 sec, 5.0 mm at approximately 0.975 sec, .6.0 mm at approximately 1.15 sec, 7.0 mm at 1.3 sec, 8.0 mm at approximately 1.567 sec, 9.0 mm at approximately 1.65 sec, and 10.0 mm at 1.8 sec. Although it would take 1.8 sec to record these 11 images, they could be replayed in 1.0 sec, at 10 frames per second.
Since the scanning procedure is performed by hand, it is possible that the user, recording the images, may cover the same volume of tissue more than once, recording images for each scan. These overlapping scans can result in redundant images and reviewing those redundant images can increase the review time. In the most elementary description of this phenomenon, if the user scans the same region twice, then the second scan is redundant. Reviewing the second scan would only repeat previously presented information. With the exception of adding a “second” review, it would not serve a clinical purpose to review the second image. In some embodiments, a redundant image is an image for which all of the information contained within that image are contained in other images, or combinations of other images. In the way of example in
In some embodiments, the phrase uniform temporal display or review refers broadly to modifying a scan sequence such that the review time satisfies a predetermined time regardless of the number of images in the scan sequence. In some cases, this is accomplished by allocating dwell times or review times for each image in the scan sequence. For example, a scan sequence having 10 images may have a predetermined review time of 10 seconds for all 10 images. However, the review time allocated to each image within the 10 image scan sequence can vary from image to image. Some images may be assigned 1.0 second dwell times. Other images may be apportioned 0.75 second dwell times. Such allotment may be a function of the relative spacing between the images. In some embodiments, uniform temporal display or review indicates that the overall total time for review of the scan sequence is substantially the same regardless of the individual dwell times or review times for each discrete image within the scan sequence.
In some embodiments, the phrase uniform spatial display or review refers broadly to modifying a scan sequence such that the relative spacing between discrete images within a scan sequence is substantially the same. For example, a scan sequence may have recorded images at 0 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.2 mm, 2.5 m, and 3.0 mm. Such a scan sequence may be modified to have uniform spatial display or review by removing images that do not have a preferred relative spacing. The relative spacing may be for example 1.0 image-to-image spacing. In this case, the recorded images for review would not include 1.5 mm, 2.2 mm, and 2.5 mm. The modified scan sequence would provide for a uniform spatial display or review.
In some embodiments, the review images may exhibit uniform spatial-temporal display or review having both uniform spatial and uniform temporal characteristics or some combination within the review scan sequence images.
Some embodiments provide for methods, systems, or devices that allow the reviewer to mark or otherwise annotate the images for review. In some cases, the annotation or marking indicates a location on the scanned image that may need to be reviewed further. In other embodiments, the marked section in the image may indicate the site of a suspicious lesion or structure, e.g., potential tumor.
Another embodiment of the present invention is seen in
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Continuing with this exemplary embodiment and referring to
Another embodiment of the present invention is further illustrated in an exploded view of the hand-held probe assembly 230 as seen in
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Accordingly, as specified in the previous paragraph, the first and second support members 242 and 244 are sized to correspond to the particular contour and dimensions of a specific hand-held ultrasonic probe design. For the case of injection-molded plastic, e.g., a biocompatible grade of polycarbonate, the inner dimensions of said first and second support members 242 and 244 are designed to closely match the outer dimensions of the hand-held ultrasound probe 214. The wall thickness of the injection molded plastic support members 242 and 244 is preferably in the range from 0.05 to 0.10 inch.
Although certain location and motion recognition methods have been described (e.g.
Furthermore, a position sensor may not be a separate sensor added to the imaging device but may be a geometric or landmark feature of the imaging device, for example, the corners of the probe. In some embodiments, the optical, infrared, or ultraviolet cameras could capture an image of the probe and interpret the landmark feature as a unique position on the imaging device. Moreover, in some embodiments, sensors may not need to be added to the imaging device. Rather, location and motion detection systems can be used to track the position of the imaging device by using geometric or landmark features of the imaging device. For example, a location system may track the corners or edges of an ultrasound imaging probe while it is scanned across a target tissue.
According to the specifications of embodiments of the present invention, either the electromagnetic radiofrequency-based method, apparatus and system or the optical recognition-based method, apparatus and system can be used to detect the position of the hand-held ultrasound probe at all time points corresponding to the time of any two-dimensional ultrasound scan image. This position and orientation data is used to compute the maximum distance between sequential two dimensional ultrasound scan images to determine if predetermined maximum spacing limits are exceeded or predetermined pixel density limits are not achieved. If any predetermined requirements are not achieved, the ultrasound screening operator is alerted with a visual display identifying that the scan just completed [a] was performed with an excessive spacing relative to the previous scan in the sequence and/or [b] was performed a rate of translation and/or rotation that was too fast to meet pixel density or spacing requirements.
Images may be retrieved and stored in a variety of manners. By way of example and as is one of the teachings in
Once the set of images is compiled, it may be stored as a set, along with the location information and other information, such as patient identification, etc., to a portable storage device 9, such as a DVD ROM, portable hard drive, network hard drive, cloud-based memory, etc. These data may be viewed on the data acquisition display module/controller 40, or an external computer equipped with software designed to review the image data.
In yet another embodiment of the present invention, an optical image projector can be included in either the Ultrasound Scan Completeness Auditing System or the Optically Based Ultrasound Scan Completeness Auditing System to superimpose optical information on the surface of the targeted tissue (e.g., the human female breast). Said optical information may, by way of example, include the ultrasound scan path(s) that need to be repeated due to excessive inter-scan distances, inadequate overlap and/or excessive scanning translation speed and/or rate of rotation. Said optical information can thereby guide the conduct of additional two-dimensional ultrasound scans to overcome any determined deficiencies.
Since certain changes may be made in the above-described system, apparatus and method without departing from the scope of the invention herein involved, it is intended that all matter contained in the description thereof or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. The disclosed invention advances the state of the art and its many advantages include those described herein.
As for additional details pertinent to the present invention, materials and manufacturing techniques may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts commonly or logically employed. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Likewise, reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “and,” “said,” and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The breadth of the present invention is not to be limited by the subject specification, but rather only by the plain meaning of the claim terms employed.
This application is a continuation of International Appl. No. PCT/US2012/059176 filed on Oct. 8, 2012 which claims the benefit of U.S. Patent Appl. No. 61/545,278, filed Oct. 10, 2011 and U.S. Patent Appl. No. 61/647,180, filed May 15, 2012, the disclosure of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61647180 | May 2012 | US | |
| 61545278 | Oct 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2012/059176 | Oct 2012 | US |
| Child | 13854800 | US |
