HELICAL CT ANGIOGRAPHY COMPARED WITH ARTERIOGRAPHY IN THE DETECTION OF RENAL-ARTERY STENOSIS

OBJECTIVE. The aim of the study was to improve the accuracy and detect ion rate for renal vascular lesions on helical CT angiography with an improved acquisition protocol and postprocessing. SUBJECTS AND METHODS . Fifty hypertensive patients (mean age, 53 years old) referred becaus e of clinical suspicion of renal artery stenosis were prospectively st udied with digital renal arteriography and helical CT angiography. A 2 0-sec helical scan (collimation, 3 mm; pitch, 1) was obtained after in jection of contrast medium. Interpretation was based on transverse sec tions, shaded-surface-display and maximum-intensity-projection reconst ructions, and two-dimensional multiplanar reconstruction cuts obtained from shaded-surface-display reconstructions. RESULTS. Arteriography v isualized 131 renal arteries (including 32 accessory arteries). Sixtee n had significant (greater than 50% in diameter) stenosis. On helical CT angiography, 14 of these 16 stenoses were detected; two were missed (false-negatives), and two additional stenoses (false-positives) were reported. Sensitivity and specificity were 88% and 98%, respectively. Considering only main renal arteries, the sensitivity and the specifi city of helical CT angiography were 100% and 98%, respectively. Helica l CT angiography detected Conn's syndrome, which was responsible for h ypertension, in two other patients. CONCLUSION. The accuracy and detec tion rate for renal artery stenosis on helical CT angiography compared with arteriography is improved with the described protocol.