3-DIMENSIONAL ULTRASOUND DEVICE FOR RAPID-DETERMINATION OF BLADDER VOLUME

Objectives, We sought to assess the accuracy, reliability, and clinica l utility of the noninvasive determination of bladder volume using an automated, compact three-dimensional (3-D) ultrasound device. Methods. We prospectively tested 249 adult outpatients for accuracy (n = 182), by comparing scan versus catheter volumes, or reliability (n = 67), b y comparing the scan readings of two independent observers. Two models of the bladder scan device were tested (BVI-2500, 1994 and 1995 model s), Results. Scan and catheter volumes were correlated (y = 1.02x + 12 .6, R-2 = 0.90, P <0.001) across a range of zero to 1015 cc, regardles s of which machine model was used. Scan volume underestimated catheter volume by an average of 10 cc in men and 20 cc in women. If a scan-pr edicted volume of 100 cc or greater were used as a cutpoint for clinic al importance, the device exhibited a sensitivity of 97%, a specificit y of 91%, and an overall accuracy of 94%. These results were not affec ted by age, gender, height, weight, diagnosis, uterine presence/prosta te size, or user experience. The two observers, one a graduate physici an and the other a college student, achieved essentially the same volu me determinations (y = 0.96x + 0.13, R-2 = 0.90, P <0.001). Conclusion s. Volume determinations obtained with the bladder scan device are acc urate and reliable in adult outpatients. A special technician is not r equired. These results may be attributable to use of automated planime try and 3-D volumetry, rather than a fixed geometric formula, to custo m measure each bladder shape. (C) 1997, Elsevier Science Inc. All righ ts reserved.