Feasibility of shutter-speed DCE-MRI for improved prostate cancer detection

The feasibility of shutter-speed model dynamic-contrast-enhanced MRI pharmacokinetic analyses for prostate cancer detection was investigated in a prebiopsy patient cohort. Differences of results from the fast-exchange-regime- allowed (FXR-a) shutter-speed model version and the fast-exchange-limit- constrained (FXL-c) standard model are demonstrated. Although the spatial information is more limited, postdynamic-contrast-enhanced MRI biopsy specimens were also examined. The MRI results were correlated with the biopsy pathology findings. Of all the model parameters, region-of-interest-averaged K ^trans difference [ΔK^trans ≡ K ^trans(FXR-a) - K^trans(FXL-c)] or two-dimensional K ^trans(FXR-a) vs. k_ep(FXR-a) values were found to provide the most useful biomarkers for malignant/benign prostate tissue discrimination (at 100% sensitivity for a population of 13, the specificity is 88%) and disease burden determination. (The best specificity for the fast-exchange-limit- constrained analysis is 63%, with the two-dimensional plot.) K^trans and k_ep are each measures of passive transcapillary contrast reagent transfer rate constants. Parameter value increases with shutter-speed model (relative to standard model) analysis are larger in malignant foci than in normal-appearing glandular tissue. Pathology analyses verify the shutter-speed model (FXR-a) promise for prostate cancer detection. Parametric mapping may further improve pharmacokinetic biomarker performance. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.