Improved repeatability of dynamic contrast‐enhanced MRI using the complex MRI signal to derive arterial input functions: a test‐retest study in prostate cancer patients

Abstract

Purpose The arterial input function (AIF) is a major source of uncertainty in tracer kinetic (TK) analysis of dynamic contrast‐enhanced (DCE)‐MRI data. The aim of this study was to investigate the repeatability of AIFs extracted from the complex signal and of the resulting TK parameters in prostate cancer patients. Methods Twenty‐two patients with biopsy‐proven prostate cancer underwent a 3T MRI exam twice. DCE‐MRI data were acquired with a 3D spoiled gradient echo sequence. AIFs were extracted from the magnitude of the signal (AIF MAGN ), phase (AIF PHASE ), and complex signal (AIF COMPLEX ). The Tofts model was applied to extract K trans , k ep and v e . Repeatability of AIF curve characteristics and TK parameters was assessed with the within‐subject coefficient of variation (wCV). Results The wCV for peak height and full width at half maximum for AIF COMPLEX (7% and 8%) indicated an improved repeatability compared to AIF MAGN (12% and 12%) and AIF PHASE (12% and 7%). This translated in lower wCV values for K trans (11%) with AIF COMPLEX in comparison to AIF MAGN (24%) and AIF PHASE (15%). For k ep , the wCV was 16% with AIF MAGN , 13% with AIF PHASE , and 13% with AIF COMPLEX . Conclusion Repeatability of AIF PHASE and AIF COMPLEX is higher than for AIF MAGN , resulting in a better repeatability of TK parameters. Thus, use of either AIF PHASE or AIF COMPLEX improves the robustness of quantitative analysis of DCE‐MRI in prostate cancer.