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 post-void residual urine.