Pretreatment Evaluation of Prostate Cancer: Role of MR Imaging and¹H MR Spectroscopy

Abstract

Magnetic resonance (MR) imaging and hydrogen 1 MR spectroscopy of the prostate gland are performed during the same examination with a conventional clinical MR unit. Prostate zonal anatomy and prostate cancer are best depicted on multiplanar T2-weighted MR images. MR imaging and 1H MR spectroscopy are not used as an initial diagnostic tool. Their use in tumor detection is reserved for patients with elevated prostate-specific antigen levels in whom previous biopsy results were negative. The use of MR imaging and 1H MR spectroscopy for the evaluation of tumor location, local extent (extracapsular extension and/or seminal vesicle invasion), volume, and aggressiveness is generating strong clinical interest. In staging and treatment planning, MR imaging has been shown to have an incremental value additive to the value of clinical nomograms. Furthermore, anatomic and metabolic mapping of the prostate gland with 1H MR spectroscopy offers the possibility of optimizing treatment planning (watchful waiting, surgery, or radiation therapy [intensity-modulated radiation therapy or brachytherapy]), thus further expanding the role of MR imaging in the achievement of patient-specific, individualized treatment.

The role of dynamic contrast enhanced MRI in the detection of recurrent prostate carcinoma after external beam radiotherapy-correlation with transrectal ultrasound and pathological findings

“…Alternatively, prostate cancer can be observed as single, multiple, or diffuse hypointense lesions in the peripheral zone in T2-weighted images (11); however, the hypointense lesions in the peripheral zone that are observed in the T2-weighted images can be the result of cancer or hemorrhage, hyperplastic nodules, inflammation, or post-radiation changes (12). Thus, a hypointense appearance is not specific for prostate cancer.…”

Prostate Cancer: The Role of Multiparametric Magnetic Resonance Imaging

“…3,21 On T1WI, generally obtained only in the axial plane, the prostate demonstrates homogeneous low-to-medium signal intensity and the zonal anatomy is impossible to discern. In contrast, T2WI should be obtained in three planes (axial, coronal and sagittal) and is able to depict the zonal anatomy (Fig.…”

“…The anterior fibromuscular stroma also has low signal intensity on T2WI. 1,2,7,16,21 The peripheral and transition zones are separated by a visible linear boundary often referred as pseudocapsule or surgical capsule. The true prostate capsule surrounds the peripheral zone and appears as a hypointense rim in T2WI.…”

“…The distal prostatic urethra appears as a low-signal-intensity ring in the lower prostate, but the proximal urethra is rarely identifiable. 1,7,16,21 …”

Previsão pré-operatória do estadiamento local do câncer prostático: análise multifatorial baseada em parâmetros clínicos, laboratoriais e de imagem por ressonância magnética e ultra-sonografia

“…As áreas, na maioria das vezes, são consideradas suspeitas quando a relação colina-creatina/citrato é pelo menos dois desvios padrões maior que a relação no tecido prostático normal e, altamente suspeitas, quando a relação colina-creatina/citrato é pelo menos três desvios padrões maior que a relação no tecido prostático normal (Kurhanewicz et al, 2002;Kurhanewicz et al, 1996). O uso combinado das imagens de ressonância magnética convencionais e da espectroscopia têm mostrado excelente sensibilidade e especificidade na localização do câncer de próstata na zona periférica, além de diminuir a variabilidade interobservadores, tanto na localização quanto no estadiamento Yu et al, 1999), permitir uma estimativa da agressividade tumoral (Kurhanewicz et al, 2002) e proporcionar uma previsão do estadiamento pré-operatório baseado no número de porções com alterações suspeitas à espectroscopia (Claus et al, 2004;Yu et al, 1999). Um grande trabalho multicêntrico com a finalidade de verificar a efetividade da ressonância magnética associada à espectroscopia no estadiamento do câncer prostático está em estádio inicial e os resultados estão sendo aguardados (Weinreb, 2003).…”