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 regional renal blood flows has been limited because of the lack of reliable, noninvasive techniques. To determine the feasibility of flow measurements with electron-beam computed tomography (EBCT), six anesthetized dogs were scanned by EBCT during basal conditions, after renal vasodilation, and at recovery. Flow (mL/min/cm3 tissue) was calculated from EBCT-derived time-density curves using three different algorithms and compared with simultaneously obtained electromagnetic flow (EMF) probe measurements after indexing to EBCT-derived renal volume. EBCT-determined flow correlated well with EMF measurements regardless of the algorithm used. An algorithm using the area under the time-density curve was concluded to be the most suitable for calculation of renal blood flow; it correlated with EMF as EBCT flow = 44.5 + 1.05 EMF (r = 0.885, SEE = 31.2 mL/min, P < .0001). Consistent overestimation of flow by EBCT resulted probably from retention of contrast media in the renal parenchyma. EMF showed an increase of 20 +/- 10% in renal blood flow after vasodilation. EBCT-derived global, cortical, and medullary flows increased by 33.8 +/- 10.3%, 24.8 +/- 17.8%, and 99.0 +/- 73.8%, respectively. In conclusion, EBCT was found feasible for credible quantitation of renal blood flow in the physiologic range studied.
Lerman
L O
LO
Department of Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Bell
M R
MR
Lahera
V
V
Rumberger
J A
JA
Sheedy
P F
PF
Sanchez Fueyo
A
A
Romero
J C
JC
D000465:Algorithms; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D004285:Dogs; D007672:Kidney Cortex / Q000098:blood supply*; D007679:Kidney Medulla / Q000098:blood supply*; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D001920:Bradykinin