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

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).

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.

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.

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 .