Method and apparatus for imaging abdominal aorta and aortic aneurysms

• US 20060264741A1
• Filed: 07/26/2006
• Published: 11/23/2006
• Est. Priority Date: 06/07/1993
• Status: Active Grant

• Current Assignee: Martin R. Prince
• Original Assignee: Martin R. Prince
• Inventors: Prince, Martin R.
• Granted Patent: US 7,680,527 B2
• Time in Patent Office: Days
• 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

1-26. -26. (canceled)

27. A method of imaging a portion of the aorta of a patient using a magnetic resonance imaging system and a magnetic resonance contrast agent, the method comprising:

temporally correlating an administration of the magnetic resonance contrast agent with an acquisition of magnetic resonance image data which is representative of the center of k-space, using an arrival time of the magnetic resonance contrast agent in a region of interest wherein the region of interest includes at least a portion of the aorta; and

acquiring the magnetic resonance image data using a 3D pulse sequence, wherein the magnetic resonance image data which is representative of the center of k-space is acquired while the concentration of the contrast agent in the portion of the aorta is greater than a concentration of the contrast agent in veins adjacent to the portion of the aorta and background tissue adjacent to the portion of the aorta.

28. The method of claim 27 further including medicating the patient to reduce the cardiac output of the patient.

29. The method of claim 27 wherein the magnetic resonance image data is processed with volume rendering.

30. The method of claim 27 wherein the magnetic resonance image data is reformatted and selectively collapsed to depict portions of the aorta and/or branch arteries of interest.

31. The method of claim 27 wherein the magnetic resonance image data is selectively collapsed through a renal artery.

32. The method of claim 27 wherein the magnetic resonance image data acquired using a 3D pulse sequence is collapsed into an image using an Maximum Intensity Projection algorithm.

33. The method of claim 27 wherein acquiring magnetic resonance image data using the 3D pulse sequence further includes using a TR which is less than about 10 milliseconds and a TE which is less than about 3 milliseconds.

34. The method of claim 27 further including instructing the patient to suspend respiration.

35. The method of claim 34 further including correlating the instruction to the patient to suspend respiration with the acquisition of the magnetic resonance image data which is representative of the center of k-space.

36. The method of claim 34 wherein acquiring the magnetic resonance image data includes acquiring magnetic resonance image data which is representative of the center of k-space while the patient suspends respiration.

37. The method of claim 34 wherein acquiring the magnetic resonance image data includes acquiring magnetic resonance image data which is representative of a substantial portion of the center of k-space while the patient suspends respiration.

38. The method of claim 27 further including imaging at least one renal artery of the patient by acquiring magnetic resonance image data of a coronally oriented image volume including the renal artery, wherein the magnetic resonance image data of the coronally oriented image volume is acquired while the concentration of the contrast agent in the renal artery is substantially greater than a concentration of the contrast agent in veins and background tissue adjacent to the artery.

39. The method of claim 27 further including imaging at least one renal artery of the patient by acquiring magnetic resonance image data including magnetic resonance image data which is representative of the center of k-space while the concentration of the contrast agent in the renal artery is substantially greater than a concentration of the contrast agent in veins and background tissue adjacent to the artery.

40. The method of claim 39 wherein imaging at least one renal artery of the patient further includes acquiring 3D phase contrast images after administering the contrast agent.

41. The method of claim 40 wherein the 3D phase contrast images are acquired using a velocity encoding value (VENC) of about 30 cm/second.

42. The method of claim 27 further including locating at least one arm of the patient overhead during acquisition of the magnetic resonance image data.

43. The method of claim 27 further including providing sufficient margin of a pre-scan for an expected increase in signal after administering contrast agent to the patient.

44. The method of claim 27 wherein the contrast agent is gadolinium.

45. The method of claim 27 wherein the contrast agent is Fe powder.

46. The method of claim 27 further including administering at least 0.2 mMol/Kg of contrast agent to the patient.

47. The method of claim 27 further including acquiring magnetic resonance image data of the periphery of k-space while the concentration of the contrast agent in the aorta is greater than a concentration of the contrast agent in veins and background tissue adjacent to the aorta.

48. The method of claim 27 further including:

acquiring magnetic resonance image data of a pre-contrast image data set including acquiring magnetic resonance image data before administering the magnetic resonance contrast agent to the patient; and

constructing an image of the portion of the aorta by subtracting the image data of the pre-contrast image data set from the image data acquired while the concentration of the contrast agent in the portion of the aorta is greater than a concentration of the contrast agent in veins and background tissue adjacent to the portion of the aorta.

49. The method of claim 27 wherein the arrival time of the magnetic resonance contrast agent in the region of interest is estimated.

50. The method of claim 27 further including determining the arrival time of a magnetic resonance contrast agent in the region of interest includes using an arrival time of a test bolus.

51. The method of claim 27 wherein acquiring magnetic resonance image data further includes using a TR which is less than about 10 milliseconds, a TE which is less than about 3 milliseconds, and a flip angle which is between about 30°

and about 90°

.

52. The method of claim 27 wherein:

acquiring magnetic resonance image data further includes acquiring the magnetic resonance image data which is representative of the center of k-space while the concentration of the contrast agent in the portion of the aorta is a maximum relative to the concentration of the contrast agent in veins and background tissue adjacent to the portion of the aorta; and

acquiring magnetic resonance image data includes acquiring magnetic resonance image data which is representative of the center of k-space near a beginning of the 3D pulse sequence followed by data which is representative of the periphery of k-space.

53. The method of claim 52 wherein acquiring magnetic resonance image data further includes using a TR which is less than about 10 milliseconds, a TE which is less than about 3 milliseconds and a slice thickness which is less than about 4 millimeters, and the image volume of the 3D pulse sequence includes at least one dimension which is at least about 25 centimeters.

54. The method of claim 52 further including:

acquiring image data of a pre-contrast image data set including acquiring magnetic resonance image data before administering the magnetic resonance contrast agent to the patient; and

constructing an image of the portion of the aorta by subtracting the magnetic resonance image data of the pre-contrast image data set from the magnetic resonance image data acquired while the concentration of the contrast agent in the portion of the aorta is greater than a concentration of the contrast agent in veins and background tissue adjacent to the portion of the aorta.

55. The method of claim 52 further including instructing the patient to suspend respiration before acquiring the magnetic resonance image data which is representative of the center of k-space.