Cortical thickness: an early morphological marker of atherosclerotic renal disease

Although kidney size is still the most commonly used morphological parameter, it is not sensitive enough for early detection of atherosclerotic renal disease (ARD). The purpose of this work was to evaluate morphological abnormalities on both post-stenotic and contralateral kidneys, by using spiral computed tomography angiography (CTA).

Spiral CTA was performed in 49 hypertensive patients. Renal diameters, renal length, and cortical thickness were measured in 26 post-stenotic kidneys, 26 contralateral kidneys and 46 control kidneys. Mean cortical thickness, cortical area, and medullary length were calculated.

The right and left control kidneys were of comparable morphology. The post-stenotic kidneys showed significant cortical atrophy. The contralateral kidneys also underwent cortical disease, as judged by comparison with control kidneys. A threshold of 800 mm2 was identified for the cortical area that allowed us to distinguish control kidneys from post-stenotic kidneys. Similarly, a threshold of 8 mm was identified for mean cortical thickness. Renal length was still within normal range in all kidney groups. The measurement of superior pole segments appeared to be more sensitive than measurement at other locations for identifying significant intrarenal lesions. There was no significant correlation between clinical and morphological parameters.

These results suggest that cortical parameters are more sensitive for early diagnosis of ARD than kidney size. Cortical atrophy should be a useful marker for guidance for revascularization.