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.

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 ), phase (AIF ), and complex signal (AIF ). The Tofts model was applied to extract K , k and v . 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 (7% and 8%) indicated an improved repeatability compared to AIF (12% and 12%) and AIF (12% and 7%). This translated in lower wCV values for K (11%) with AIF in comparison to AIF (24%) and AIF (15%). For k , the wCV was 16% with AIF , 13% with AIF , and 13% with AIF .

Conclusion: Repeatability of AIF and AIF is higher than for AIF , resulting in a better repeatability of TK parameters. Thus, use of either AIF or AIF improves the robustness of quantitative analysis of DCE-MRI in prostate cancer.