OBJECTIVE: The purpose of this study was to retrospectively evaluate the impact of multiparametric prostate MRI, including diffusion-weighted imaging (DWI) performed using different b values as well as dynamic contrast-enhanced MRI (DCE-MRI) on the accuracy, sensitivity, and specificity for transition zone (TZ) tumor detection and localization.
MATERIALS AND METHODS: We included 106 prostate cancer patients (mean age [± SD], 62 ± 7 years) who underwent 3-T MRI with a pelvic phased-array coil before radical prostatectomy. Three radiologists independently reviewed cases to record the likelihood of tumor in each of six TZ regions. Scores were initially assigned using T2-weighted imaging alone, reassigned after integration of DWI at b = 1000 s/mm2 and corresponding apparent diffusion coefficient (ADC) maps, reassigned again after integration of DWI at b = 2000 s/mm2, and reassigned a final time after integration of DCE-MRI. Generalized estimating equations based on binary logistic regression were used to compare sessions for TZ tumor detection, using prostatectomy findings as reference standard.
RESULTS: Of the TZ sextants, 9.7% (62/636) contained tumor. All readers had higher sensitivity for T2-weighted imaging integrated with DWI at b = 1000 s/mm2 and ADC compared with T2-weighted imaging alone (reader 1, 54.8% vs 33.9%; reader 2, 53.2% vs 22.6%; and reader 3, 50.0% vs 19.4% [p ≤ 0.002]); two readers had further increased sensitivity also incorporating b = 2000 s/mm2 (reader 1, 74.2% and reader 2, 62.9%; p ≤ 0.011), and one reader had further increased sensitivity also incorporating both b = 2000 s/mm2 and DCE-MRI (reader 3, 61.3%, p = 0.013). DCE-MRI otherwise did not improve sensitivity (p ≥ 0.054). Other measures were similar across the four sessions (reader 1, specificity 97.4-98.3% and accuracy 91.2-95.9%; reader 2, specificity 95.8-98.4% and accuracy 91.0-92.6%; reader 3, specificity 90.9-96.7% and accuracy 88.1-89.2%).
CONCLUSION: DWI assists TZ tumor detection through higher sensitivity, particularly when using a very high b value; DCE-MRI lacks further additional benefit.
Rosenkrantz AB, Kim S, Campbell N, Gaing B, Deng FM, Taneja SS. Are you the author?
Department of Radiology, Center for Biomedical Imaging, NYU School of Medicine, NYU Langone Medical Center, 660 First Ave, 3rd Fl, New York, NY 10016.
Reference: AJR Am J Roentgenol. 2015 Mar;204(3):W266-72.