Prostate MRI for the detection of extracapsular extension.

Volume 95 No. 5 May 2012 a sixTy-year old Male was found To have a palpable prostatic nodule on screening digital rectal examination. A serum prostatic specific antigen (PSA) assay yielded a concentration of 25.8 ng/ml (normal range 0-4 ng/ml). A transrectal ultrasound guided 12-core biopsy was then performed and confirmed Gleason 8 (4+4) and 9 (4+5) disease involving left side greater than right, was also demonstrated with associated hematospermia on the left. (Figures 3a, 3b, and 3c) The previously identified left obturator lymph node was also re-identified and noted to be mildly enlarged with restricted diffusion, remaining suspicious for regional nodal metastasis. (Figure 4) While surgical resection remains the most widely accepted curative treatment option for those with organ-confined disease, if there is evidence of extracapsular extension (T3 disease), surgery may result in an increased risk of incomplete resection, higher likelihood of micrometastatic disease elsewhere in the body, and higher morbidity. High-risk patients, therefore, especially those with evidence of seminal vesicle invasion or nodal metastases, are better served with alternative therapies such as external beam radiation and/or brachytherapy, hormonal therapy, and/ or chemotherapy. For high-risk patients such as this, an MRI of the prostate gland using both a torso phased array coil and an endorectal coil remains the most sensitive imaging technique for local staging to guide Urologic management between primary surgical resection versus other less invasive treatment options. The use of an endorectal coil is essential to obtain adequate signal and spatial resolution to resolve and stage tumors of the prostate. Traditionally, this has involved the use of a small field of view with high resolution T2 weighted images obtained in the axial, coronal, and sagittal planes where tumors appear hypointense upon a background of the normally hyperintense peripheral zone. Extracapsular extension is evident when there is disruption of the prostatic capsule, asymmetry in the neurovascular bundle, seminal vesicle invasion, or invasion into adjacent organs such as the bladder or rectum. While T2 signal hypointensity can also be seen with nonmalignant findings such as hemorrhage, prostatitis, and Prostate mRi For the detection of extracapsular extension