[Diagnostic imaging of prostate cancer].

Cancer nodules in early prostate cancer are mostly visualized as hypoechoic lesions on ultrasonogram. In a small number of prostate cancers, the cancer nodule is isoechoic and difficult to visualize. In advanced prostate cancer, the prostate is enlarged asymmetrically and deformed. The internal echo pattern of the prostate with advanced prostate cancer has usually been demonstrated as a mixed or mosaic architecture including both hypoechoic and hyperechoic lesions. According to several reporters, the sensitivity and specificity of transrectal sonography were approximately 80% and 90%, respectively. Doppler color flow imaging was applied to transrectal sonography in the present study. The detection rate of blood flow image was higher in the cases of prostate cancer than in other cases with normal or benign prostatic hyperplasia. The detection rate became higher according to the stage of the disease, but no difference was noticed among cases with different tumor grades. Blood flow rapidly became lower after castration and was undetectable 4 weeks after the treatment. CT scan was not useful for the diagnosis of prostate cancer. MRI seemed promising because it can visualize the internal architecture and cancer lesion of the prostate.