Method for imaging abdominal aorta and aortic aneurysms

• US 5,799,649 A
• Filed: 09/19/1996
• Issued: 09/01/1998
• Est. Priority Date: 06/07/1993
• Status: Expired due to Term

• Current Assignee: Martin R. Prince
• Original Assignee: Martin R. Prince
• Inventors: Prince, Martin R.
• Primary Examiner(s): Casler, Brian L.
• Application Number:
  US08/715,736
• Time in Patent Office: 712 Days
• Field of Search: 128/653.3, 128/653.4, 128/653.2, 128/654, 128/655, 128/659, 324/307, 324/309, 424/9.3, 424/9.36
• US Class Current: 600/420
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/201 Assessing renal or kidney functions
• CPC Class Codes: A61B 5/416 the spleen
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: A61K 49/18 characterised by a special physical form, e.g. emulsions, microcapsules, liposomes
• CPC Class Codes: G01R 33/281 Means for the use of in vitro contrast agents G01R33/282 takes precedence; involving use of a contrast agent in MR imaging G01R33/5601; in vivo contrast agents A61K49/0002
• CPC Class Codes: G01R 33/5619 by temporal sharing of data, e.g. keyhole, block regional interpolation scheme for k-Space [BRISK]
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography
• CPC Class Codes: G01R 33/56308 Characterization of motion or flow; Dynamic imaging

Abstract

The present invention is a technique and apparatus for acquiring anatomic information used in diagnosing and characterizing abdominal aortic aneurismal disease and the like. This technique provides anatomic information, in the form of images, using a combination of a plurality of magnetic resonance angiography sequences, including a spin-echo and four contrast enhanced (e.g., gadolinium) magnetic resonance angiography sequences. The anatomic images may be used in, for example, pre-operative, operative and post-operative evaluation of aortic pathology, including aneurysms, atherosclerosis, and occlusive disease of branch vessels such as the renal arteries. The gadolinium-enhanced magnetic resonance angiography provides sufficient anatomic detail to detect aneurysms and all relevant major branch vessel abnormalities seen at angiography operation. This technique and apparatus allows for imaging the aorta at a fraction of the cost of conventional aortography and without the risks of arterial catheterization or iodinated contrast.

Claims

1. A method of imaging an aorta of a patient using magnetic resonance imaging, comprising,

performing a first imaging sequence for locating the aorta;

performing a second imaging sequence to provide at least one image of the aorta, including,

administering a substantial portion of a magnetic resonance contrast agent to the patient; and

collecting image data which is representative of a substantial portion of a center of k-space while the concentration of the contrast agent in the aorta is substantially higher than a concentration of the contrast agent in veins and background tissue adjacent to the aorta.

2. The method of claim 1 wherein the first imaging sequence is a sagittal T1 weighted sequence.

3. The method of claim 1 wherein the second imaging sequence is a plurality of images constructed from a 3D image sequence and the step of collecting image data further includes collecting a substantial portion of the center of k-space while a flip angle is between about 20°

to about 90°

, TR≦

30 milliseconds and TE≦

7 milliseconds.

4. The method of claim 3 wherein the plurality of images include at least one of a plurality of coronal, sagittal and oblique projections.

5. The method of claim 1 further including the step of performing at least an imaging sequence for imaging a size of the aortic aneurysm.

6. The method of claim 5 wherein the imaging sequence for imaging a size of the aortic aneurysm includes collecting image data for a plurality of one of a sagittal and axial 2D time-of-flight images and further includes collecting a substantial portion of the imaging data while the patient suspends respiration.

7. The method of claim 1 wherein the second imaging sequence further includes collecting a portion of the image data which is representative of the center of k-space while the concentration of the contrast agent in the artery is substantially a maximum.

8. The method of claim 1 further including performing an imaging sequence for imaging renal arteries.

9. The method of claim 8 wherein the step of performing the imaging sequence for imaging renal arteries further includes collecting phase contrast images.

10. The method of claim 8 wherein the step of performing the imaging sequence for imaging renal arteries further includes collecting 3D phase contrast images.

11. A method of imaging aorta using magnetic resonance imaging, comprising,

performing a first imaging sequence for locating the aorta;

performing a second imaging sequence to obtain at least one image of the aorta, including,

administering a magnetic resonance contrast agent to the patient; and

collecting image data which is representative of at least a substantial portion of a center of k-space while the concentration of the contrast in the aorta is about a maximum relative to adjacent veins and background tissue.

12. The method of claim 11 wherein the first imaging sequence is a sagittal T1 weighted sequence.

13. The method of claim 11 wherein the second imaging sequence is a plurality of images constructed from a 3D imaging sequence and wherein the plurality of images include at least one of a plurality of coronal, sagittal and oblique projections.

14. The method of claim 11 further including the step of performing at least one imaging sequence for imaging a size of an aortic aneurysm.

15. The method of claim 14 wherein the at least one imaging sequence for imaging a size of an aortic aneurysm includes collecting image data for a plurality of sagittal and axial 2D time-of-flight images.

16. The method of claim 11 wherein the step of performing the second imaging sequence includes collecting at least a substantial portion of the image data while the patient suspends respiration.

17. The method of claim 11 further including performing an imaging sequence for imaging renal arteries.

18. The method of claim 17 wherein the step of performing the imaging sequence for imaging renal arteries further includes collecting phase contrast images.

19. The method of claim 17 wherein the step of performing the imaging sequence for imaging renal arteries further includes collecting 3D phase contrast images.

20. A method of imaging portions of an aorta in a patient using magnetic resonance imaging, comprising,

performing a imaging sequence for locating the aorta;

performing a 3D imaging sequence to obtain at least one image of the aorta, including,

administering a magnetic resonance contrast agent to the patient; and

collecting image data which is representative of a portion of a center of k-space while a concentration of the contrast agent in the aorta is substantially higher than a concentration of the contrast agent in veins and background tissue adjacent to the aorta, wherein the image data is collected using a flip angle which is between about 20°

to about 90°

.

21. The method of claim 20 wherein the first imaging sequence is a sagittal T1 weighted sequence.

22. The method of claim 20 wherein the 3D imaging sequence is a 3D spoiled gradient echo pulse sequence and the step of collecting image data which is representative of a center of k-space includes collecting image data wherein TR≦

30 milliseconds and TE≦

7 milliseconds.

23. The method of claim 20 wherein the step of collecting image data further includes collecting image data which is representative of a substantial portion of a center of k-space while a concentration of the contrast agent in the aorta is substantially higher than a concentration of the contrast agent in veins and background tissue adjacent to the aorta.

25. A method of imaging aorta of a patient using magnetic resonance imaging, wherein the aorta includes a lumen, the method comprising,

performing a first imaging sequence for locating the aorta;

performing a second imaging sequence to image at least a portion of the lumen, including,

administering a magnetic resonance contrast agent to the patient; and

collecting image data which is representative of a center of k-space while the concentration of the contrast agent is substantially higher than a concentration of contrast agent in veins and background tissue adjacent to the aorta.

26. The method of claim 25 wherein the step of performing the second imaging sequence includes collecting at least a substantial portion of the image data while the patient suspends respiration.

27. The method of claim 25 further including the step of performing an imaging sequence for imaging a size of an aortic aneurysm after the step of performing the second imaging sequence.

28. A method of imaging an aorta in a patient using magnetic resonance imaging, comprising,

performing a first imaging sequence for locating the aorta;

performing a second imaging sequence to image at least a portion of the aorta, including,

administering a magnetic resonance contrast agent to the patient; and

collecting data which is representative of a center of k-space when a concentration of the contrast agent in the aorta is substantially higher than a concentration of the contrast agent in veins and background tissue adjacent to the aorta.

24. The method of claim 30 wherein the 3D imaging sequence further includes collecting a portion of the image data which is representative of the center of k-space while the concentration of the contrast agent in the aorta is about a maximum relative to adjacent veins and background tissue.

29. The method of claim 28 wherein the step of collecting data includes using a 3D gradient echo imaging sequence.

30. The method of claim 29 wherein the step of collecting data includes a flip angle of between about 20°

to about 90°

, TR≦

30 milliseconds and TE≦

7 milliseconds.

31. The method of claim 29 further including performing a substantially sagittal, T1 weighted sequence to identify a location of an aneurysm prior to performing the 3D gradient echo imaging sequence.

32. The method of claim 29 wherein the step of performing the 3D gradient echo pulse sequence includes collecting data for constructing a plurality of images including one of a plurality of substantially coronal, sagittal and oblique projections.

33. The method of claim 29 further including the step of performing a plurality of 2D time-of-flight imaging sequences for imaging a size of the aneurysm.

34. The method of claim 29 further including performing an imaging sequence for imaging renal arteries by collecting phase contrast images.

35. The method of claim 28 wherein the step of administering a magnetic resonance contrast agent includes administering the contrast agent to the patient by bolus injection.

36. The method of claim 35 wherein the step of collecting data which is representative of the center of k-space includes collecting at least a substantial portion of the data while the patient suspends respiration.

37. The method of claim 28 wherein the step of collecting data which is representative of a center of k-space includes collecting data when the concentration of the contrast agent in the aorta is about a maximum relative to adjacent veins and background tissue.

38. The method of claim 37 wherein the step of collecting data which is representative of a center of k-space includes collecting data while a flip angle is between about 20°

to about 90°

, TR≦

30 milliseconds and TE≦

7 milliseconds.

39. The method of claim 28 further including performing an imaging sequence for imaging peripheral arteries.

40. The method of claim 28 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data while a field of view is greater than about 30 centimeters.

41. The method of claim 28 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data while a slice thickness is less than 5 millimeters.

42. The method of claim 28 further including determining an arrival of the contrast agent in a region of interest.

43. The method of claim 42 further including imaging rapidly to determine the arrival of the contrast agent in the region of interest.

44. The method of claim 28 wherein the step of performing the second imaging sequence includes using a body coil.

45. The method of claim 44 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data using a coronally oriented imaging volume.

46. A method of imaging a portion of an aorta in a patient using magnetic resonance imaging, wherein the aorta includes a lumen, said method comprising,

performing an imaging sequence to obtain at least one image of the lumen, including,

administering a magnetic resonance contrast agent to the patient;

and

collecting a substantial portion of image data which is representative of a center of k-space while a concentration of the contrast agent in the aorta is substantially higher relative to adjacent veins and background tissue.

47. The method of claim 46 wherein the step of administering a magnetic resonance contrast agent to the patient includes administering the contrast agent to the patient by bolus injection.

48. The method of claim 46 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data while a flip angle is between about 20°

to about 90°

, TR≦

30 milliseconds and TE≦

7 milliseconds.

49. The method of claim 46 further including performing an imaging sequence for imaging renal arteries wherein the imaging sequence includes collecting 3D phase contrast images.

50. The method of claim 46 wherein the step of collecting data which is representative of the center of k-space includes using a 3D gradient echo pulse sequence.

51. The method of claim 46 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data while a field of view is greater than about 30 centimeters.

52. The method of claim 46 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data while a slice thickness is less than 5 millimeters.

53. The method of claim 46 wherein the step of performing an imaging sequence includes using a body coil.

54. The method of claim 53 wherein the step of collecting image data which is representative of the center of k-space includes collecting image data using a coronally oriented imaging volume.