Correlation of Ultrasound-Estimated Bladder Weight with Ultrasound Appearance of the Prostate and Postvoid Residual Urine in Men with Lower Urinary Tract Symptoms

Abstract

Objectives. To reveal the possible relationship of urodynamic tests and transrectal sonography (TRS) of the prostate with bladder hypertrophy as evaluated by ultrasound-estimated bladder weight (UEBW) in men with lower urinary tract symptoms. Methods. In a total of 234 men aged 50 years or more with a normal prostate or benign prostatic hyperplasia (BPH) as determined by TRS, UEBW was correlated with age, the American Urological Association (AUA) symptom score, postvoid residual urine, maximum flow rate, and transrectal ultrasound planimetry such as prostatic volume and presumed circle area ratio (PCAR). Results. In a simple regression analysis there was a statistically significant correlation between UEBW and the AUA symptom score ( R = 0.282, P <0.0001), postvoid residual urine ( R = 0.490, P <0.0001), prostatic volume ( R = 0.358, P <0.0001), and PCAR ( R = 0.468, P <0.0001). A multiple regression analysis demonstrated postvoid residual urine and PCAR to be significant independent determinants of UEBW. The frequency of abnormal UEBW (35.0 g or more) increased significantly with postvoid residual urine ( P <0.0001) and PCAR ( P <0.0001). Conclusions. Postvoid residual urine and PCAR were useful parameters for the evaluation of the severity of BPH in terms of bladder hypertrophy probably due to infravesical obstruction.