Fibromuscular dysplasia of the renal arteries: comparison of helical CT angiography and arteriography.

OBJECTIVE: We evaluated the role of helical CT angiography rendering techniques in the assessment of renal artery fibromuscular dysplasia. MATERIALS AND METHODS: Twenty hypertensive patients (mean age, 56 years) with angiographically proven renal artery fibromuscular dysplasia were studied by CT angiography. The acquisition protocol was collimation, 3 mm; table speed, 3 mm/sec; and incremental algorithm, one. Maximum-intensity-projection and shaded-surface-display reconstructions and transverse sections were reviewed by a consensus panel to determine the sensitivity and specificity of each technique in revealing renal artery fibromuscular dysplasia. RESULTS: Helical CT angiography enabled successful diagnosis of fibromuscular dysplasia in all 20 patients. Helical CT angiography showed 31 of 34 pathologic arteries and 33 of 38 lesions. Aneurysms (>6 mm) on arteriography (n = 12) were revealed in 83% of transverse sections, 75% of maximum-intensity-projection reconstructions, and 58% of shaded-surface-display reconstructions. Lesions that had a string of pearls appearance on arteriography (n = 19) were shown in 53% of transverse sections, 84% of maximum-intensity-projection reconstructions (p < .05 compared with transverse sections), and 74% of shaded-surface-display reconstructions. Stenoses (n = 7 on arteriography) were revealed in 57% of transverse sections, 71% of maximum-intensity-projection reconstructions, and 57% of shaded-surface-display reconstructions. Maximum intensity projection alone revealed 30 (79%) of the 38 angiographic lesions; however, using both maximum intensity projections and transverse sections increased the sensitivity to 87%. CONCLUSION: Helical CT angiography, especially the combination of transverse sections and maximum-intensity-projection reconstructions, can reliably reveal renal artery fibromuscular dysplasia. However, because some lesions may not be shown, arteriography with pressure measurements remains the only technique that can assess the physiologic significance of the dysplasia.

Popliteal vascular disease: evaluation with spiral CT angiography.

PURPOSE: To evaluate the potential role of spiral computed tomographic (CT) angiography in the diagnosis of popliteal artery disease. MATERIALS AND METHODS: In 26 consecutive patients referred for popliteal arteriography, the authors performed additional spiral CT angiography with the following protocol: 3-5-mm collimation, 4-6 mm/sec table speed, and 2-3-mm overlap during 32 seconds, with use of 110 mL of contrast medium. Axial transverse sections and shaded surface display and multiplanar reformation reconstruction images were analyzed. All patients underwent previous Doppler ultrasound examination. RESULTS: In the 52 arteries imaged, arteriography showed 14 isolated hemodynamically significant (>50% diameter reduction) stenoses (due to popliteal artery entrapment in one case), four occluded arteries, and 11 aneurysms. CT angiography also demonstrated these 14 stenoses and four occlusions. However, axial transverse views at CT angiography showed that eight of the stenoses were associated with other abnormalities (aneurysm in six, popliteal artery entrapment syndrome in one, and cystic adventitial disease in one) and that two of the occlusions resulted from popliteal artery entrapment syndrome (n = 1) and thrombosis of an aneurysm (n = 1). CT angiography also demonstrated the 11 aneurysms shown with arteriography. CONCLUSION: Popliteal artery lesions can be diagnosed with spiral CT angiography, which provides detailed information on the wall and diameter of the artery and relation of the artery to adjacent structures.