Objective:To assess renal morphology using spiral computed tomographic angiography (CTA) before and 6 months after angioplasty of unilateral atherosclerotic renal artery stenosis (RAS).Methods:Spiral CTA scans from 14 hypertensive patients (7 men; mean age 57.4 ± 13.1 years) with significant RAS were performed before and 6 months after angioplasty; renal length, mean cortical thickness (MCT), cortical area (CA), and medullary length (ML) were measured from the axial slices in the 14 contralateral and 14 poststenotic then revascularized kidneys. Blood pressure, creatinine clearance, and number of antihypertensive drugs were analyzed.Results:At 6 months, the systolic blood pressure was significantly reduced (p=0.007), but the number of antihypertensive drugs and the creatinine clearance did not change significantly. Most morphological parameters before and after angioplasty were different in the contralateral versus poststenotic kidneys (renal length, p=0.01; MCT, p=0.01; ML, p=0.03; CA, p=0.008). After angioplasty, there was an 11% drop in cortical atrophy associated with a mean 4-mm increase in medullary length in the poststenotic/revascularized kidneys. The contralateral kidneys exhibited corticomedullary thinning after angioplasty.Conclusions:In atherosclerotic renal disease, cortical thinning could be a useful timesaving marker to assess the significance of the lesion and to evaluate associated distal lesions. The favorable blood pressure outcome supports the existence of reversible ischemic lesions, particularly in the medulla. Angioplasty appears to be useful for the poststenotic kidney, according to the morphological study.