Evaluation of prostate volume by transabdominal ultrasonography with modified ellipsoid formula at different stages of benign prostatic hyperplasia.

The aim of the study was to propose an eccentricity parameter (EP)-based correction to the ellipsoid formula to improve the evaluation of the prostate volume defined by transabdominal ultrasonography (TAUS) at different stages of benign prostatic hyperplasia (BPH). All 202 adult male volunteers underwent the prostate volume evaluations with TAUS and computerized tomography (CT). Based on the EP index, three clearly different stages of BPH were also deduced by analytical analysis. By applying the correction formula, the mean prostate volume differences of TAUS with CT were improved from 28.1%, -25.4% and -0.6% to 7.6%, -3.5% and -0.6% for EP < 0.055, 0.055 < EP < 0.14 and EP > 0.14, respectively. Hence, for EP > 0.14, representing the advanced stage of BPH, TAUS with the ellipsoid formula can be regarded as an effective tool for computing volume, whereas for EP < 0.14, the correction formula is recommended to improve the volume estimation based on TAUS.