Renal multigated spectral Doppler imaging before and after captopril challenge.

Abstract

A new method of measurement, simultaneous multigated spectral Doppler imaging (MSDI), was used to quantify the hemodynamic changes in kidneys after administration of captopril. Forty kidneys in 22 hypertensive patients were included in the study. All underwent MSDI and scintigraphy before and after administration of captopril. With scintigraphy used as the gold standard for diagnosing renal artery stenosis (RAS), three kidneys were found to be positive for RAS. Multigated spectral Doppler imaging detected a decrease in the resistive index after administration of captopril in all patients with RAS and correctly excluded RAS in one patient who was diagnosed as having RAS on scintigraphy. The resistive index was increased after captopril administration in normally functioning kidneys and was unchanged in kidneys with impaired function. With further supportive evidence, MSDI may prove to be a powerful tool for the acquisition of resistive index information and may increase the value of the resistive index as a physiological hemodynamic parameter in the evaluation of normal and abnormal conditions.