[Ultrasonographic assessment of bladder volume].

Introduction: The aim of this study is to evaluate intra and inter-observatory variability in the sonography measurement of bladder volume.

Materials And Methods: We have evaluated 138 patients (128 men and 10 women) affected by lower urinary tract symptoms with a mean age of 64 years (range 36-75) between December 2000 and June 2001. Sonography measurement of bladder volume was obtained at the end of a pressure/flow study with the double lumen catheter in situ. Measurement of bladder volume was performed by the same operator in 113 patients by calculating the transverse, longitudinal and anterior-posterior diameter; each measurement was repeated three times. In the remaining 25 patients examination was performed by three different operators for every patients, with a single evaluation for each operator. The real volume was measured by emptying the bladder using the urethral catheter.

Results: The real bladder volume in the intra and inter-observatory group was 240 +/- 130 and 145 +/- 97, respectively. First, second and third measurement in the intra-observatory group were 229 +/- 113, 231 +/- 112, 234 +/- 127, respectively. On the other hand, first, second and third measurement in the inter-observatory group were 131 +/- 73, 129 +/- 66, 143 +/- 94, respectively.

Conclusions: Looking at our results, it is clear that there is no significant difference between every single measurement in the intra and inter-observatory group. In addition, the estimation of bladder volume by ultrasound was quite similar to the real volume. We conclude that ultrasound is a precise, non invasive and highly reproducible technique to calculate the bladder volume.