INTRAOBSERVER AND INTEROBSERVER VARIABILITY AND RELIABILITY OF PROSTATE VOLUME MEASUREMENT VIA 2-DIMENSIONAL AND 3-DIMENSIONAL ULTRASOUND IMAGING

We describe the results of a study to evaluate the intra- and inter-ob server variability and reliability of prostate volume measurements mad e from transrectal ultrasound (TRUS) images, using either the (optimal ) height-width-length (HWL) method (V = pi/6 HWL) with two-dimensional (2D) TRUS images (obtained as cross-sections of three-dimensional [3D ] TRUS images) or manual planimetry of 3D TRUS images (the 3D US metho d). In this study, eight observers measured 15 prostate images, twice via each method, and an analysis of variance (ANOVA) was performed. Th is analysis shows that, with the 3D US method, intra-observer prostate volume estimates have 5.1% variability and 99% reliability, and inter -observer estimates have 11.4% variability and 96% reliability, With t he HWL method, intra-observer estimates have 15.5% variability and 93 % reliability, and inter-observer estimates have 21.9% variability and 87% reliability. Thus, in vivo prostate volume estimates from manual planimetry of 3D TRUS images have much lower variability and higher re liability than HWL estimates from 2D TRUS images. (C) 1998 World Feder ation for Ultrasound in Medicine & Biology.