A noninvasive ultrasonic system to determine residual bladder volumes

The authors fabricated and tested a prototype noninvasive device for determining residual bladder volume in humans. The device uses A-mode ultrasound with controlled, manual spherical scanning of the abdomen to cover 100 degrees horizontal and 80 degrees vertical. 320 A mode signals (5 degrees increments) are digitized and analyzed to determine the volume of urine in the bladder. Data from 37 subjects (18 with bladder dysfunction, 19 without) produced a mean error (estimated minus measured volumes) of -1.9+or-28 cm/sup 3/.<>