Accuracy of prostate volume measurements using transrectal multiplanar three-dimensional sonography

The aim of this study is to evaluate the accuracy of three-dimensional (3D) ultrasound in comparison with conventional bidimensional (2D) sonography in prostatic calculations. The study was performed using a Kretztechnik Voluson 530D machine with a 7.5 MHz endocavitary transducer. From March 1998 to March 2000, we examined 80 patients (63-74 years, mean 68 years). There were 59 patients with benign prostate hypertrophy (BPH) and 21 with prostate cancer awaiting a radical prostatectomy. The mean absolute error in 3D ultrasound measurement was +/- 0.2-3 mL. (range of error was 6.5%). Volume measurement using 2D ultrasound methods was much less accurate than 3D ultrasound methods: +/- 0.4-5 mL. (range of error was 35%). Both 2D and 3D measurements show that the margin of error depends on the frequent presence of a third prostatic lobe, on the morphology, and on the size of the prostatic gland. The precise estimation of prostate volumes may provide information on the real effectiveness of some therapies that act on the reduction in volume of benign alteration, such as in prostatic hypertrophy, and may eliminate the current limits of 2D sonography with a signicant clinical contribution for virtually no extra cost.