Claims
- 1. A negative contrast agent used in magnetic resonance imaging of the gastrointestinal tract comprising:
- a suspension having a substantial portion of a first constituent consisting of barium sulfate particles and a substantial portion of a second constituent comprising particles selected from at least one of the group of materials consisting of pharmaceutically acceptable clays, said second constituent constituting at least two percent by weight of said suspension, a substantial portion of said barium sulfate particles having a mean diameter sufficiently large to provide a relative signal intensity substantially less than 0.5 in at least one of the MRI pulse sequence modes.
- 2. The negative contrast agent of claim 1 wherein said mean diameter of said portion of said barium sulfate particles is at least ten microns.
- 3. The negative contrast agent of claim 1 wherein said second constituent is a smectite clay.
- 4. The negative contrast agent of claim 2 wherein said second constituent is a smectite clay.
- 5. The negative contrast agent of claim 1 wherein said second constituent constitutes at least two percent by weight of said suspension.
- 6. The negative contrast agent of claim 2 wherein said second constituent constitutes at least two percent by weight of said suspension.
- 7. The negative contrast agent of claim 1 wherein at least ten percent by weight of said suspension is constituted by barium sulfate particles having a mean diameter of at least ten microns.
- 8. The negative contrast agent of claim 2 wherein at least fifteen percent by weight of said suspension is constituted by barium sulfate particles having a mean diameter of at least ten microns.
- 9. The negative contrast agent of claim 1 wherein at least twenty-five percent by weight of said suspension is constituted by barium sulfate particles having a mean diameter of at least ten microns.
- 10. The negative contrast agent of claim 7 wherein said second constituent constitutes at least two percent by weight of said suspension.
- 11. The negative contrast agent of claim 8 wherein said second constituent constitutes at least two percent by weight of said suspension.
- 12. The negative contrast agent of claim 9 wherein said second constituent constitutes at least two percent by weight of said suspension.
Parent Case Info
This application is a 371 of PCT/US94/05604, filed May 19, 1994 which is a continuation-in-part of U.S. patent application Ser. No. 08/065,192 filed in May 20, 1993, now U.S. Pat. No. 5,424,142 issued Jun. 13, 1995 and having the same title as does this application.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/US94/05604 |
5/19/1994 |
|
|
11/13/1995 |
11/13/1995 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO94/27499 |
12/8/1994 |
|
|
US Referenced Citations (5)
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
65192 |
May 1993 |
|