Proper Measurement of the Prostate Volume by Transrectal Ultrasound: Experimental Study about the Prostate with Focal Intravesical Protrusion of the Enlarged Central Gland

ABSTRACT

PURPOSE: To evaluate the proper volume measurement of prostate with focal intravesical protrusion of enlarged central gland by comparison between methods using craniocaudal length from top of protruded central gland and from prostate base near bladder neck to prostate apex. MATERIALS AND METHODS: We made 20 prostate models with focal intravesical protrusion (volume range 20~50 mL, height of protrusion about 1 cm) using devil's tongue jelly. Two radiologists measured volume of models 3 times by two kinds of methods using craniocaudal length from top of protruded central gland (method 1) and from prostate base near bladder neck (method 2) by transrectal ultrasound. The accuracy of volume measurement of models was evaluated statistically by comparing their average volume to true volume. Intra- and interobserver agreement was also evaluated. RESULTS: Average true volume of models was 31.05 mL. Each average volume using method 1 by two observers was 37.07 mL and 38.56 mL. Each average volume using method 2 was 30.69 mL and 31.55 mL. Volume measurement using method 2 was approximated to true volume of prostate statistically (p = .654, .823). There was no significant inter- and intra-observer variation in both methods. CONCLUSION: To measure the accurate volume of porstate with focal intravesical protrusion of enlarged central gland, its craniocaudal length should be measured from prostate base near bladder neck.