Detection of extracapsular extension of prostate cancer: role of fat suppression endorectal MRI.
OBJECTIVE
The purpose of this work was to compare the efficacy of fat-suppressed and non-fat-suppressed fast spin echo (FSE) endorectal MRI in the detection of extracapsular extension (ECE) of prostate cancer by experienced and inexperienced readers.


METHODS
Seventy-nine patients with biopsy-proven prostate cancer underwent axial FSE T2-weighted endorectal MRI of the prostate prior to radical prostatectomy. Twenty-one patients were imaged with frequency-selective fat suppression, and 58 were imaged without fat suppression. All images were retrospectively and independently reviewed by two readers of different experience levels who were blinded to clinical and pathological findings. Readers assessed the presence or absence of ECE on a 5 point scale for each side of the prostate, and step-section pathology was used as the standard of reference 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 reader demonstrated better diagnostic performance (p < 0.05) than the less experienced reader in terms of sensitivity and area under the ROC curve (Az) for MRI without fat suppression. Use of frequency-selective fat suppression did not result in any significant improvement in diagnosis of ECE compared with MRI without fat suppression for either the experienced (Az 0.81 vs. 0.79) or the inexperienced (Az 0.76 vs. 0.68) reader.


CONCLUSIONS
Even when reader experience is considered, use of frequency-selective fat suppression did not significantly improve the diagnosis of ECE by MRI. The decision to use fat suppression and the selection of a fat suppression technique can be left to the discretion of the individual reader.
Department of Radiology, University of California at San Francisco 94143-0628, USA.
K
K
Tsuda
K K
KK
Yu
F V
FV
Coakley
S K
SK
Srivastav
J E
JE
Scheidler
H
H
Hricak
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity