QUANTIFICATION OF GLOBAL AND REGIONAL RENAL BLOOD-FLOW WITH ELECTRON-BEAM COMPUTED-TOMOGRAPHY

Alterations in renal blood flow distribution may occur in a variety of pathophysiologic situations; however, quantification of global and re gional renal blood flows has been limited because of the lack of relia ble, noninvasive techniques. To determine the feasibility of flow meas urements with electron-beam computed tomography (EBCT), six anesthetiz ed dogs were scanned by EBCT during basal conditions, after renal vaso dilation, and at recovery. Flow (mL/min/cm(3) tissue) was calculated f rom EBCT-derived time-density curves using three different algorithms and compared with simultaneously obtained electromagnetic flow (EMF) p robe measurements after indexing to EBCT-derived renal volume. EBCT-de termined flow correlated well with EMF measurements regardless of the algorithm used. An algorithm using the area under the time-density cur ve was concluded to be the most suitable for calculation of renal bloo d flow; it correlated with EMF as EBCT flow = 44.5 + 1.05 EMF (r = 0.8 85, SEE = 31.2 mL/min, P < .0001). Consistent overestimation of flow b y EBCT resulted probably from retention of contrast media in the renal parenchyma. EMF showed an increase of 20 + +/- in renal blood flow af ter vasodilation. EBCT-derived global, cortical, and medullary flows i ncreased by 33.8 +/- 10.3%, 24.8 +/- 17.8%, and 99.0 +/- 73.8%, respec tively. In conclusion, EBCT was found feasible for credible quantitati on of renal blood flow in the physiologic range studied.