Detection of extracapsular extension of prostate cancer: Role of fat suppression endorectal MRI

Purpose: The purpose of this work was to compare the efficacy of fat-suppre ssed and non-fat-suppressed fast spin echo (FSE) endorectal MRI in the dete ction of extracapsular extension (ECE) of prostate cancer by experienced an d inexperienced readers. Method: Seventy-nine patients with biopsy-proven prostate cancer underwent axial FSE T2-weighted endorectal MRI of the prostate prior to radical prost atectomy. Twenty-one patients were imaged with frequency-selective fat supp ression, and 58 were imaged without fat suppression. All images were retros pectively and independently reviewed by two readers of different experience levels who were blinded to clinical and pathological findings. Readers ass essed the presence or absence of ECE on a 5 point scale for each side of th e prostate, and step-section pathology was used as the standard of referenc e in all patients. Receiver operating characteristics analysis was used to compare the performance of fat-suppressed and non-fat-suppressed images by both readers. Results: ECE was present in 33 of 79 (42%) patients. The more experienced r eader demonstrated better diagnostic performance (p < 0.05) than the less e xperienced reader in terms of sensitivity and area under the ROC curve (A(z )) for MRI without fat suppression. Use of frequency-selective fat suppress ion did not result in any significant improvement in diagnosis of ECE compa red with MRI without fat suppression for either the experienced (A(z) 0.81 vs. 0.79) or the inexperienced (A(z) 0.76 vs. 0.68) reader. Conclusion: Even when reader experience is considered, use of frequency-sel ective fat suppression did not significantly improve the diagnosis of ECE b y MRI. The decision to use fat suppression and the selection of a fat suppr ession technique can be left to the discretion of the individual reader.