NORMAL RENAL-ARTERY SPECTRAL DOPPLER WAVE-FORM - A CLOSER LOOK

PURPOSE: To characterize the spectral Doppler tracing of the normal re nal artery. MATERIALS AND METHODS: Doppler tracings were obtained from a phantom of a vessel with variable compliance and from the kidneys o f 15 healthy volunteers. RESULTS: In the phantom, vascular compliance had the following effects on systolic flow velocity patterns: low comp liance, little change in the sharp appearance of the systolic componen t of the transmitted pulse; mildly increased compliance, downstream da mpening of early systolic acceleration (ESA) with the appearance of a sharp early systolic transmitted peak and of a more rounded late systo lic compliance peak; high compliance, delayed and diminished transmitt ed peak that eventually disappeared within the enlarging downstream co mpliance peak. Healthy subjects with compliant vessels had greater ESA and more frequently visualized early systolic peaks in the renal hilu m than in the renal sinus. CONCLUSION: Absence of a discrete early sys tolic peak is a normal finding in young patients, especially in the mo re distal interlobar arteries. Loss of the early systolic peak may be explained on the basis of vascular compliance.