The value of contrast enhanced power Doppler ultrasonography in differentiating hypoehoic lesions in the peripheral zone of prostate.

To characterize the hypoechoic prostate nodules in the peripheral zone by means of power Doppler ultrasonography (PDUS) and contrast enhanced PDUS (CE-PDUS).Thirty-two patients with dijital rectal examination findings suspicious for malignancy and/or a serum PSA level higher than 4 ng/dl, and who had hypoechoic nodules on transrectal ultrasonography were enrolled in this prospective study. Power Doppler ultrasonography (PDUS) images before and after sonocontrast (Levovist) injection were photographed for further evaluation. All patients were also evaluated by a systematic and nodule targeted biopsy approach. The photographs were re-evaluated by two radiologists for the presence and type of vascularity. The type of vascularity was categorized as peripheral, central, mixed and penetrating. The latter two were accepted as representatives of malignancy. The results of PDUS and CE-PDUS were compared to each other and to the pathological results.There was a high level of interobserver agreement (Kappa: 0.80-0.95). Nineteen patients, but only 14 nodules were malignant on pathological examination. Sensitivity, specificity positive and negative predictive values for PDUS were 57, 50, 47, and 60%, respectively. On CE-PDUS, the sensitivity increased (93%) in expense of specifity (17%). The positive and negative predictive values were 46 and 75%, respectively. There was no significant difference between PDUS and CE-PDUS.This study revealed that both benign and malignant nodules might be hypervascular and show malignant type of vascularity on PDUS. Contrary to some recent reports, we can conclude that the CE-PDUS does not provide a considerable aid to the diagnosis of prostate carcinoma on morphological basis due to its very low specificity despite its relatively higher sensitivity.