Effects of bladder volume on transabdominal ultrasound measurements of intravesical prostatic protrusion and volume

Abstract

Background : A filled bladder acts as an acoustic window for transabdominal ultrasound measurements of intravesical prostatic protrusion and volume. The aim of this study is to evaluate the effects of bladder volume on transabdominal ultrasound measurements of these parameters. Methods : Twenty-two patients undergoing transurethral resection of the prostate (TURP) were studied. Under general anesthesia just before TURP, a transrectal ultrasound measurement of prostate volume was obtained. The bladder was then filled in a stepwise manner with 100, 200, 300, 400 and 500 mL. At each volume, the intravesical prostatic protrusion and prostatic volume were measured transabdominally using ultrasound.Results : There was an obvious trend of decreasing mean transabdominal intravesical prostatic protrusions with increasing bladder volume. The mean transabdominal intravesical prostatic protrusion at bladder volumes 100, 200, 300, 400 and 500 mL was 9.1, 8.8, 7.4, 5.8 and 4.6 mm, respectively. The bladder volume at which maximum prostatic protrusion occurred was between 100 and 200 mL. The mean transabdominal prostate volume at the five increasing bladder volumes was 50.6, 48.7, 49.2, 47.9 and 41.4 mL, and these were correlated to transrectal prostate volume, particularly when the bladder volume was less than 400 mL. Conclusions : Transabdominal ultrasound measurement of prostatic protrusion is dependent on bladder volume. Transabdominal ultrasound measurement of prostatic volume correlates well with the transrectal measurement of the same parameter when the bladder volume is less than 400 mL.

Urodynamic Evaluation of Patients with Lower Urinary Tract Symptoms and Small Prostate Volume

“…Although transrectal ultrasound is considered more accurate, a number of studies demonstrate good correlation between the two methods and acceptable accuracy for the transabdominal route [16][17][18] . Moreover, the transabdominal ultrasound tends to overestimate the prostate volume in comparison with the transrectal technique, which indicates that the prostate volume of the studied population could be even smaller than the estimated.…”

Singapore Urological Association Clinical Guidelines for Male Lower Urinary Tract Symptoms/Benign Prostatic Hyperplasia

“…(8) Obstruction at the bladder outlet depends on not just the size but, more so, the site of the adenoma. (3) Prostate adenoma causes distortion of the bladder neck and protrudes into the bladder lumen, which is seen as intravesical prostatic protrusion (IPP) on ultrasonography (10) (Fig. 1).…”

Noninvasive Methods to Evaluate Bladder Obstruction in Men

“…TRUS tends to be the most frequently used due to its availability and good size estimation [23]. DRE is a poor assessor of prostate size, making TRUS even more useful (18).…”

“…IPP grades are < 5mm, 5-10mm, or > 10mm respectively (22). Bladder volume at the time of measurement may significantly impact the measurement of IPP, thus studies have shown that a bladder volume of 100-200 mL is ideal (23). As the grade of IPP increases, so too will the severity of BOO.…”