47 - Prostate Cancer Within the Transition Zone: Gadolinium-Enhanced Magnetic Resonance Imaging

Abstract

Prostate carcinoma is the most common cancer in males over 50 years of age and remains a leading cause of cancer death. Accurate preoperative staging and early detection are very important in selecting the therapeutic strategies for prostate cancer. Magnetic resonance (MR) imaging has been gaining acceptance as an important tool in the evaluation of prostate cancer—mainly that occurs in the peripheral zone. Although most prostate cancers originate in the peripheral zone, up to 30% of prostate cancers occur within the transition zone. Transition zone cancer has made substantial contributions to the morbidity and mortality of prostate cancer. MR imaging is used for evaluating prostate cancer focusing on transition zone cancer. On T2-weighted images, the transition zone has lower signal intensity than the peripheral zone. MR imaging using gadolinium enhancement can be useful in the detection and differentiation of transition zone cancer from other benign lesions such as BPH nodules. Cancer is considered present on MR image analysis when there is uniform low signal intensity on T2-weighted images, homogeneous gadolinium enhancement, or where the interface between the lesion and the inner gland is irregular on gadolinium-enhanced and T2-weighted images. However, all other nodules showing heterogeneous low intensity with regular margins and heterogeneous gadolinium enhancement are considered benign lesions.