Significant changes in transrectal ultrasonic measurements of the prostate in relation to the degree of rectal wall distension

The present study was conducted to reveal the possible changes in transrectal ultrasonic measurements of the prostate in relation to the degree of rectal wall distension. When analyzed together for 51 men, all measurements but area changed statistically significantly as the rectal wall was distended by a balloon covering a probe. Ultrasonic measurements concerning the prostatic shape changed more remarkably than those concerning its size. More importantly, changes in ultrasonic measurements were much more remarkable in patients with a healthy prostate than in those with an advanced BPH. These results suggest that possible changes in prostatic shape with the rectal wall distension has to be taken into account when evaluating transrectal prostatic ultrasonograms in terms of changes in shape, especially in patients with a healthy prostate. This is also the case when the diagnosis of BPH is made based on the change in shape, such as presumed circle area ratio, which is a parameter representing the roundness of the horizontal sonogram of the prostate.