Ultrasound assessment of intravesical prostatic protrusion and detrusor wall thickness--new standards for noninvasive bladder outlet obstruction diagnosis?

Abstract

Purpose: We evaluated the accuracy of detrusor wall thickness and intravesical prostatic protrusion, and the association of each test to diagnose bladder prostatic obstruction in patients with lower urinary tract symptoms. Materials and Methods: We enrolled in the study 100 consecutive patients with lower urinary tract symptoms due to benign prostatic hyperplasia. Baseline parameters were International Prostate Symptom Score, prostate volume, urinary flow rate, intravesical prostatic protrusion, detrusor wall thickness, Schaefer obstruction class, minimal urethral opening pressure and the urethral resistance algorithm bladder outlet obstruction index. A ROC curve was produced to calculate AUC and evaluate the diagnostic performance of intravesical prostatic protrusion, detrusor wall thickness and prostate volume for bladder prostatic obstruction. Results: We noted a highly significant correlation between intravesical prostatic protrusion and the bladder outlet obstruction index (Spearman's rho = 0.49, p = 0.001), and Schaefer obstruction class (Spearman's rho = 0.51, p = 0.001). A highly significant correlation was also observed for detrusor wall thickness and the bladder outlet obstruction index (Spearman's rho = 0.57, p = 0.001), detrusor wall thickness and Schaefer obstruction class (Spearman's rho = 0.432, p = 0.02). On multivariate analysis intravesical prostatic protrusion and detrusor wall thickness were the only parameters associated with bladder prostatic obstruction (p = 0.015). The AUC for intravesical prostatic protrusion was 0.835 (95% CI 0.756-0.915) and for detrusor wall thickness it was 0.845 (95% CI 0.78-0.91). The association of intravesical prostatic protrusion and detrusor wall thickness produced the best diagnostic accuracy (87%) when the 2 tests were done consecutively. Conclusions: Suprapubic ultrasound of detrusor wall thickness and intravesical prostatic protrusion is a simple, noninvasive, accurate system to assess bladder prostatic obstruction in patients with lower urinary tract symptoms due to benign prostatic hyperplasia. Editorial CommentRecently attempts have been made to provide noninvasive tests for the assessment of bladder outlet obstruction (BOO). Since prostate volume and post void residual urine are not accurate parameters in predict-

Intravesical Prostate Protrusion (IPP) versus Middle Lobe Volume on Ultrasonography in Assessing the Impact of Benign Prostatic Hyperplasia

“…Indeed, more the volume of the prostate increases, more the IPP becomes marked. Agbo A.C. et al [4] in Nigeria (p = 0.002), Franco G et al [8] in Italy (p = 0.01) also found a significant link between IPP and prostate volume.…”

Does the Combination of Intravesical Prostatic Protrusion and Bladder Outlet Obstruction Number Increase Test Accuracy According to Benign Prostatic Obstruction at the Individual Level?

“…At the same time, higher sensitivity and specificity of this factor were proved compared with bladder wall thickness (BWT), although BWT according to other studies shows a very high accuracy in predicting infravesical obstruction (4, 19). However, accurate determination of bladder or detrusor wall thickness requires adequate maximum bladder volume, adequate place of the transducer for bladder wall measurement and optimized ultrasound transducer frequency (20). …”