Angiographic measurement of renal compartments. Corticomedullary ratio in normal, diseased states and sickle cell anemia.

Renal cortical thickness cannot be estimated by excretory urography because cortical material only partially occupies the space between calyces and renal border. This space was investigated by renal arteriography and venography. The corticomedullary junction was demarcated by arcuate arteries and veins and in the nephrogram phase, cortical thickness was measured directly. These studies showed that the cortex occupies only 45–55% of the. distance beyond the calyces, the remainder being medullary substance. In most diseases, changes in renal size do not affect the corticomedullary ratio, indicating parallel changes in both components. Some cases of sickle cell anemia showed paradoxical renal enlargement with cortical thinning and a reduced corticomedullary ratio.