Radionuclide measurement of bladder emptying rate. Simultaneous comparison with urinary flow rate obtained by uroflowmetry.

Mean and peak bladder emptying rates were measured by a radionuclide method using a gamma camera and Tc-99m DTPA and were compared with average and maximum urinary flow rates obtained by a uroflowmeter in 24 simultaneous measurements. A good correlation was found between the two methods. Average urinary flow rate correlates better with mean bladder emptying rate (r = 0.96, y = 1.04X + 0.14, s.e.e. = 1.2) than maximum urinary flow rate with peak bladder emptying rate (r = 0.83, y = 0.78X + 4.5, s.e.e. = 4.2). The results suggest that the radionuclide method can be used to measure the urinary flow rate, and has the advantage of establishing the postvoid residual urine.