Patent Application
20100286524
This invention relates to diagnostic ultrasound imaging systems and, in particular, to a system and method for allowing ultrasound images to be organized and displayed in a manner that is related to the respective heart cycles during which the images were obtained.
One of the advantages that diagnostic ultrasound has had over many other diagnostic imaging modalities is the ability to produce realtime images. The advantage has been especially significant in cardiology where the physiology of a continually moving organ, the heart, are the subject of study. Realtime imaging has been a virtual necessity in echocardiography as compared with abdominal and obstetrical applications where the tissues and organs being studied are stationary and may be readily examined by static imaging. Echocardiologists, like other practitioners of diagnostic ultrasound, make records of their ultrasound examinations for subsequent diagnosis, review, and comparison. Since echocardiography studies use realtime ultrasonic imaging, they are conventionally recorded on videotape with a VCR, rather than being recorded statically on film or as photographic prints. A VCR has been an essential accessory for an echocardiography system for many years. More recently, it has been possible to stream digital data in real time as images corresponding to the data are obtained. This digital data can be saved by storing the data on an optical disk such as a digital video disk (“DVD”), which is capable of recording large volumes of data, such as image data generated during an ultrasound examination.
The advantage of being able to digitally record the large volume of image data generated during an ultrasound examination carries with it the disadvantage of making it difficult to organize the data for subsequent analysis of the images represented by the data. More specifically, the large volume of image data obtained during, for example, a cardiac ultrasound examination, makes it difficult to find images having specific characteristics or images that were taken during a specific cardiac event. Therefore, the large volume of data makes it even more important to be able to organize the data so that it can be subsequently accessed in a meaningful way. Also, although video cassette tapes can store a large volume of digital data, the organization of stored data for easy access is really not an issue because such tapes are can store data only in a linear manner, thus making random access to such data impossible regardless of how the data is organized. DVDs, on the other hand, allow random access to any portion of the stored data, but this benefit cannot be taken advantage of unless the data is organized in a meaningful way. Unfortunately, DVDs, being designed primarily for multimedia use, have very limited flexibility for organizing data, thus making it difficult to organize in a logical manner the ultrasound images stored on a DVD.
There is therefore a need for an ultrasound imaging system that can store image data on a DVD in an organized manner that readily allows images to be subsequently display in a logical manner.
A system and method of obtaining and recording an ultrasound image uses an ECG monitor to provide an ECG waveform that is processed to identify each of a plurality of heart cycles. Ultrasound is transmitted into a region of interest during at least some of the plurality of heart cycles, and resulting ultrasound echoes are received. These ultrasound echoes are converted into corresponding sets of echo signals, which are then delayed and summed to form coherent echo signals. A plurality of sets of the coherent echo signals, each corresponding to a portion of the same image, are processed to form respective sets of digital image data corresponding to a respective ultrasound image obtained during respective heart cycles. The digital image data are then divided into sections identified using the ECG waveform so that each section of digital image data corresponds to a respective ultrasound image obtained during a respective one of the plurality of heart cycles. The digital image data may be coupled to a digital video disk recorder, which records the digital image data on a digital video disk. The digital image data are recorded on the disk in chapters corresponding to the respective sections into which the digital image data was divided. Data corresponding to the ECG waveform divided into respective chapters may also be recorded on the digital video disk along with the corresponding chapters of the digital image data.
A diagnostic ultrasound imaging system 100 according to one example of the invention is shown in
The transducer elements 112 in the probe 110 are connected through a transmit/receive (“T/R”) switch 114 to a transmitter 117. The transmitter 117 is connected to a central controller 120, which causes the transmitter 117 to output an ultrasound signal at a desired time, transmit frequency ftr, and duration. The transmitter 117 applies the ultrasound signal through the T/R switch 114 to the transducer elements 112 in the probe 110. The transducer elements 112 then emit ultrasound into a planar or volumetric region beneath the probe 110. The transmitter 117 may also adjust the relative phases of the signals applied to the transducer elements 112 to either steer the transmitted ultrasound in a desired direction and/or to focus the transmitted ultrasound to a desired depth.
The transmitted ultrasound is reflected from anatomical features in the linear or volumetric region being examined, and the reflected ultrasound echoes are coupled to the transducer elements 112. The transducer elements 112 then produce corresponding echo signals, which are coupled through the T/R switch 114 and digitized by an analog-to-digital (“A/D”) converter 115. The sampling frequency fs of the A/D converter 115 is controlled by the central controller 120. The desired sampling rate dictated by sampling theory is at least twice the highest frequency of the received passband of the echo signals. Sampling rates higher than the minimum requirement are also desirable.
The echo signal samples from the individual transducer elements 112 are delayed and summed by a digital beamformer 116 to form coherent echo signals. The digital coherent echo signals are then filtered by a digital filter 118. In one example of the system 100, the transmit frequency ftr may be different from the passband frequency of the digital filter so that the digital filter 118 can pass signals having a frequency that is a harmonic of a fundamental frequency ftr of the transmitted ultrasound. The received echo signals may then be further processed, for instance by processing to remove artifacts such as speckle, by a digital signal processor 124.
The echo signals, after being filtered by the digital filter 118 and processed by the digital signal processor 124, are detected and processed by either a B mode processor 126 or a contrast signal detector 128 for display as a two or three dimensional ultrasonic image. The echo signals are also coupled to a Doppler processor 130 for Doppler processing to produce velocity and power Doppler signals which may be used to produce a colorflow, spectral, or power Doppler 2D image. The outputs of these processors 126, 128, 130 are also coupled to a 3D image rendering processor 136 for the rendering of three dimensional images, which are stored in a 3D image memory 138. Three dimensional rendering may be performed as described in U.S. Pat. No. 5,720,291, and in U.S. Pats. Nos. 5,474,073 and 5,485,842, the latter two patents illustrating three dimensional power Doppler ultrasonic imaging techniques. The signals from the B-mode processor 126, the contrast signal detector 128, and the Doppler processor 130 are coupled to a video processor 140 where they may be selected for two or three dimensional display on an image display 150 as dictated by user selection. The persistence of the displayed image and possibly other display parameters are controlled by the central controller 120.
The video processor 140 is also coupled to a streaming digital video processor 160 which processes image signals corresponding to signals received from the B-mode processor 126, the contrast signal detector 128 or the Doppler processor 130. More specifically, the streaming digital video processor 160 converts the image signals to streaming digital data in a desired digital video format. For example, the streaming digital data may be compressed to mpeg-2 format, which is suitable for recording on a DVD recorder 170. The streaming digital video processor 160 may output the streaming digital data to an external data port 174 as well as to the DVD recorder 170. Images corresponding to the streaming digital data can then be viewed by an external device (not shown) in real time or recorded by an external device (not shown) for subsequent viewing.
The streaming digital video processor 160 also receives an indexing signal Si from an ECG processor 180, which is, in turn, connected to an ECG monitor 184. The streaming digital video processor 160 uses the indexing signal Si from the ECG processor 180 to divide the streaming digital data into sections so that each section contains digital data for a respective heart cycle. The location in the heart cycles where each section begins and ends is controlled by the central controller 120. The ECG processor 180 also outputs on bus 190 ECG data indicative of an ECG waveform obtained by the ECG monitor 184. The streaming digital video processor 160 converts the ECG data into streaming ECG data, which is divided into the sections so that each section contains ECG data for the portion of the ECG waveform obtained during a respective heart cycle. The sections of streaming digital data and the sections of streaming ECG data are associated with each other so that the ultrasound image and ECG waveform obtained during the same heart cycle can be displayed together.
When the streaming digital data and streaming ECG data are applied to the DVD recorder 170, the DVD recorder 170 records a DVD with a large number of chapters, each of which contains digital data for a respective section of streaming digital data and a respective section of streaming ECG data. The DVD may also contain audio indicative, for example, of Doppler sounds or containing comments of a sonographer conducting the ultrasound examination from which the images were obtained. Further, as is well-known in the art, the images recorded on the DVD can be viewed with an index listing the chapters sequentially numbered. Using this index, a chapter containing an image recorded during a cardiac or other event can be easily located for subsequent viewing. Further, by recording the ultrasound images on a DVD, the images can be stored in a patient's chart in the form of the DVD. Also, the images may be viewed on any device that is capable of playing DVDs, such as personal computers and common DVD players. Although the streaming digital data is described as being recorded on a DVD, it will be understood that it also may be recorded on other and subsequently developed digital video recording media such as, for example, high definition digital video disks (“HDDVDs”) and the like.
An example of an ultrasound image recorded on a DVD by the DVD recorder 170 is shown on a screen 200 of the display 150 (
With further reference to
Finally, the index portion 214 contains a listing of chapters on the DVD, each of which corresponds to a respective heart cycle. In the probable event that there are too many recorded chapters to be displayed in the index portion 214, the chapter corresponding to the heart cycle shown in the center of the ECG waveform portion 212 is located at the center of the chapter listing in the index portion 214. However, other chapter indexing formats may also be used.
The ultrasound imaging system 100 is therefore capable of recording a vast amount of image data in a manner that is organized to permit any heart cycle and desired image to be easily located. Further, when reviewing the ultrasound images, any image of significance can be easily noted for subsequent review by simply noting the corresponding chapter. Finally, the ultrasound images recorded by the system 100 are stored on a DVD where they can be viewed by readily available playback devices.
Although the present invention has been described with reference to the disclosed embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Such modifications are well within the skill of those ordinarily skilled in the art. Accordingly, the invention is not limited except as by the appended claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB07/52665 | 7/6/2007 | WO | 00 | 1/9/2009 |
| Number | Date | Country | |
|---|---|---|---|
| 60807401 | Jul 2006 | US |
