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

OBJECTIVE. We evaluated the role of helical CT angiography rendering techni ques in the assessment of renal artery fibromuscular dysplasia. MATERIALS AND METHODS. Twenty hypertensive patients (mean age, 56 years) wi th angiographically proven renal artery fibromuscular dysplasia were studie d by CT angiography. The acquisition protocol was collimation, 3 mm; table speed 3 mm/sec; and incremental algorithm, one. Maximum-intensity-projectio n and shaded-surface-display reconstructions and transverse sections were r eviewed by a consensus panel to determine the sensitivity and specificity o f each technique in revealing renal artery fibromuscular dysplasia. RESULTS. Helical CT angiography enabled successful diagnosis of fibromuscul ar dysplasia in all 20 patients. Helical CT angiography showed 31 of 34 pat hologic arteries and 33 of 38 lesions. Aneurysms (>6 mm) on arteriography ( n = 12) were revealed in 83% of transverse sections, 75% of maximum-intensi ty-projection reconstructions, and 58% of shaded-surface-display reconstruc tions. Lesions that had a string of pearls appearance on arteriography (n = 19) were shown in 53% of transverse sections, 84% of maximum-intensity-pro jection reconstructions (p < .05 compared with transverse sections), and 74 % of shaded-surface-display reconstructions. Stenoses (n = 7 on arteriograp hy) were revealed in 57% of transverse sections, 71% of maximum-intensity-p rojection reconstructions, and 57% of shaded-surface-display reconstruction s. Maximum intensity projection alone revealed 30 (79%) of the 38 angiograp hic lesions; however, using both maximum intensity projections and transver se sections increased the sensitivity to 87%. CONCLUSION. Helical CT angiography, especially the combination of transvers e sections and maximum-intensity-projection reconstructions, can reliably r eveal renal artery fibromuscular dysplasia. However, because some lesions m ay not be shown, arteriography with pressure measurements remains the only technique that can assess the physiologic significance of the dysplasia.