Application of dynamic computed tomography to physiologic imaging of renal artery stenosis before and after angioplasty.

This study describes the application of dynamic Computed Tomography (CT) of the kidneys to the diagnosis and evaluation of the physiology of renal artery stenosis before and after angioplasty. The CT imaging parameters are discussed in relationship to findings from other imaging modalities, which include renal arteriography, intravenous digital subtraction angiography, and radionuclide renography. Time density graphs of the renal cortex and medulla were obtained by the use of region of interest cursors, and the corticomedullary junction time (CMJT) was determined. The CMJT was prolonged in the setting of renal artery stenosis and was improved after angioplasty. Simple visual inspection alone provided sufficient information to diagnose renal artery stenosis. The pathophysiology of renal artery stenosis and the meaning of the abnormal findings is discussed. Dynamic CT provides a unique noninvasive means for cross-sectional physiologic imaging. The role of dynamic CT in the evaluation of renovascular hypertension and physiologic imaging in other areas requires further investigation.