The Clinical Value of Residual Urine Checked by Transrectal Ultrasonography

Abstract

Purpose: Post-voiding residual urine hasbeen evaluated by urethral catheterization or abdomen ultrasonography in patients with benign prostatic hyperplasia. However, urethral catheterization is invasive and abdomen ultrasonography is not cost-effective for patients with benign prostatic hyperplasia. Therefore, we wished to determine the efficacy of using transrectal ultrasonography for the evaluation of the residual urine volume. Materials and Methods: A total of 37 patients were evaluated. The mean age of the patients was 69 years, ranging from 54-84 years. The empty bladder was instilled with a random volume of saline. In addition, the bladder volume was checked by transrectal ultrasonography. Results: The total mean residual urine volume checked by transrectal ultrasonography and catheterization were different statistically. When we performed a simple linear regression of the residual urine volume determined by each method, the regression coefficient was 0.699 and the determination coefficient was 58.4%. We divided the patients into two groups one group of patients with a residual urine volume of 150ml and the other group of patients with a prostate volume of 40ml. When the residual urine volume was less than 150ml and the prostate volume was less than 40ml, each mean residual urine volume was not different statistically. The determination coefficient was more than 60% by the simple linear regression. Conclusions: We could use transrectal ultrasonography for the purpose of a residual urine volume check. Especially when the residual urine volume was less than 150ml and the prostate volume was less than 40ml, we could estimate the residual urine volume by transrectal ultrasonography more accurately. (Korean J Urol 2007;48:951-955)