MR-IMAGING (INCLUDING MR-ANGIOGRAPHY) OF ABDOMINAL AORTIC-ANEURYSMS -COMPARISON WITH CONVENTIONAL ANGIOGRAPHY

OBJECTIVE. The purpose of this report is to compare the results of MR imaging, including MR angiography, with the results of conventional an giography in the imaging of abdominal aortic aneurysms (AAA). SUBJECTS AND METHODS. Twenty seven nonconsecutive patients with known AAA unde rwent both MR imaging (including MR angiography) and conventional angi ography preoperatively. MR imaging was done before angiography accordi ng to the following protocol in all patients: sagittal and coronal Tf- weighted images of the abdomen, followed by axial MR angiograms obtain ed with a multiple overlapping thin-slab acquisition (MOTSA) three-dim ensional time-of-flight (3D TOF) volume centered on the renal arteries . Last, coronal MR angiograms were obtained with a dynamic contrast-en hanced 3D TOF volume centered on the aorta. Conventional angiography w as subsequently performed in all patients. Data from each study were c ollected prospectively and analyzed in a blinded manner. For the MR st udies, all sequences were used to determine the extent of the AAA and the presence of iliac aneurysms; stenotic disease of the celiac, super ior mesenteric, renal, and iliac arteries and the number and location of renal arteries were determined from the MR angiograms. For evaluati on of the extent of the aneurysm, results from both techniques were co mpared with surgical results; otherwise MR angiography was compared wi th conventional angiography, Confidence intervals for sensitivity and specificity were calculated at the 95% level, The McNemar test was use d for comparison of proportions. RESULTS, MR angiography had a sensiti vity of 100% (4/4) and a specificity of 91% (21/23) for the four steno ses of the celiac artery that were greater than 50%. For detection of renal artery stenoses of greater than 50%, present in nine arteries, t he sensitivity was 89% (8/9) and specificity was 98% (49/50). MR angio graphy showed 100% (54/54) of all main renal arteries and 78% (7/9) of all accessory renal arteries seen on conventional angiograms. The pro ximal extent of the aneurysm was correctly predicted on the basis of M R findings in 100% (26/26) of patients with surgical correlation, comp ared with 92% (24/26) when conventional angiograms were used. This dif ference was not statistically significant (p > .1). MR imaging had a s ensitivity of 100% (19/19) for detection of isolated aneurysms of the common iliac artery, and MR angiography had a 100% sensitivity (5/5) a nd specificity (103/103) for detection of stenoses greater than 50% in the common and external iliac arteries. One circumaortic left renal v ein was visualized on MR images. CONCLUSION. These results suggest tha t MR angiography may be a useful noninvasive method of determining the presence of coexistent celiac, superior mesenteric, renal, and iliac atherosclerotic disease in patients with AAA.