[Functional MRI by general radiologists in prediction of side-specific extracapsular extension after radical prostatectomy: what value in daily practice?]

Abstract

Objective: To evaluate the performance of functional MRI (FMRI) performed by general radiologists (GR) in detection of side-specific extracapsular extension (SSECE) prostate cancer (PCa).

Methods: We retrospectively analyzed 79 patients who underwent FMRI with pelvic phased array coil before radical prostatectomy (RP) performed at University Hospital (UH) of Nîmes. Twelve GR (including three from UH) interpreted the images during their daily practice. FMRI results were dichotomized as positive or negative and confronted to pathological reports for SSECE and side-specific seminal vesicle invasion (SSSVI), with calculation of diagnostic values. The influence of interval between biopsy and FMRI, diffusion-weighted sequence (DWS) and intensity of FMRI, on the diagnostic performance were assessed by Fisher's exact test.

Results: A SSECE and a SSSVI were observed at FMRI and pathology respectively on 14 (8.8%) and 38 (24.1%) prostate lobes, and on six (3.8%) and seven (4.4%) prostate lobes. The sensitivity, specificity, positive and negative predictive values of FMRI for SSECE were respectively 24%, 96%, 64% and 80%; and for SSSVI were 14%, 97%, 17% and 96% respectively. The time between biopsy and FMRI, intensity of FMRI and DWS, did not influence the sensitivity and specificity of fMRI at Fisher test.

Conclusion: This study found that preoperative prostate FMRI performed by GR has good specificity but poor sensitivity in predicting SSECE on pathological reports.