[Ultrasonographic assessment of intravesical urine volume]

The assessment of intravesical urine volume is very important in the management of the patients with lower urinary tract obstruction or incontinence. As the non-invasive method for measuring residual urine volume, accuracy and usefulness of ultrasonographic measurement was evaluated in a total of 116 occasions in comparison with the conventional catheter technique. The values of the maximum transverse (W), cranio-caudal (H) and antero-posterior distance (D) of the inflated bladder were obtained by trans-abdominal scanning. These parameters were used for the ellipsoid formula (pi/6 x W x H x D). The ultrasonographic measurement of urine volume showed a high coefficiency against the conventional catheterized volume (r = 0.9543). Although a mean standard error was 56.3% of the actual volume, the amount of residual urine at the target of 50 ml and 100 ml could be accurately assessed by ultrasound with an accuracy of 90.5%. The method was also valid in follow-up study to monitor the changes of residual urine volume. The ultrasonographic assessment of intravesical urine volume is, thus, a non-invasive, useful tool in the management of the patients with voiding disturbance.