Urinary bladder blood flow.

The blood flow of the dog urinary bladder measured by radioactive microsphere technique was compared to the clearance of locally injected Technetium pertechnate (Tc) in the bladder wall. In semilogarithmic plots the Tc washout curves showed a multiexponential course. From the initial slopes (median 5.7 min) the bladder blood flow was calculated to be only 30-62% of the results obtained from the radioactive microsphere technique (blood flow in the muscular layer 21.7-44.8 ml/ 100 g/min). These lower values imply that the rate of removal of the hydrophilic tracer Tc at these flow rates is limited by the capillary diffusion capacity. The multiexponential curves reflect recirculation and excretion of Tc by the kidneys with accumulation of Tc in the bladder. It is concluded, that clearance studies of locally injected Tc in the bladder wall are unable to evaluate bladder blood flow. [ABSTRACT FROM AUTHOR]