Assessing the vascular-stromal coefficient in patients with benign prostatic hyperplasia or prostate cancer using transrectal ultrasonography and power Doppler analysis.

Abstract

To assess a coefficient of the prostatic blood supply in patients with prostate cancer or benign prostatic hyperplasia (BPH), and thus improve the diagnostic and prognostic variables needed to evaluate patients with prostate cancer. The vascular-stromal coefficient was defined as the ratio of the blood vessel surface area and the surface area of the prostate, using power Doppler functions and transrectal ultrasonography. The index was calculated for the plane of the prostatic surface from the apex to the widest points of the peripheral zone, and for the plane across the highest density of blood vessels in the transition zone. A micobubble contrast agent was used to intensify the acoustic signals from prostatic vessels. The images were reconstructed in three dimensions. In all, 61 patients with BPH and 32 with confirmed prostate cancer were examined, and compared with a control group of young men. In the horizontal plane crossing the apex of the prostate, the vascular-stromal coefficient was 0.0054 for the controls, 0.0072 for BPH and 0.0067 for cancer. At the level of the highest density of blood vessels the respective values were 0.0083, 0.038 and 0.029. The respective values for the first plane after using the contrast agent were 0.025, 0.092 and 0.0365, and in the second level 0.04, 0.15 and 0.14. The vascular-stromal coefficient measured at both levels was higher in patients with BPH than in those with cancer or than in the controls. The prostatic vascular system can be computer-reconstructed in three dimensions, allowing an evaluation of asymmetry and other vascular abnormalities. The contrast agent effectively increases the vascular acoustic signals from the prostate, enhancing by a factor of five the visualization of blood vessels when using the power Doppler option.