Accuracy, repeatability, and interplatform reproducibility of T1 quantification methods used for DCE-MRI: Results from a multicenter phantom study

PurposeTo determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T-1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3T. MethodsA T-1 phantom with 14 samples was imaged at eight centers with a common inversion-recovery spin-echo (IR-SE) protocol and a variable flip angle (VFA) protocol using seven flip angles, as well as site-specific protocols (VFA with different flip angles, variable repetition time, proton density, and Look-Locker inversion recovery). Factors influencing the accuracy (deviation from reference NMR T-1 measurements) and repeatability were assessed using general linear mixed models. Interplatform reproducibility was assessed using coefficients of variation. ResultsFor the common IR-SE protocol, accuracy (median error across platforms=1.4-5.5%) was influenced predominantly by T-1 sample (P<10(-6)), whereas test-retest repeatability (median error=0.2-8.3%) was influenced by the scanner (P<10(-6)). For the common VFA protocol, accuracy (median error=5.7-32.2%) was influenced by field strength (P=0.006), whereas repeatability (median error=0.7-25.8%) was influenced by the scanner (P<0.0001). Interplatform reproducibility with the common VFA was lower at 3T than 1.5T (P=0.004), and lower than that of the common IR-SE protocol (coefficient of variation 1.5T: VFA/IR-SE=11.13%/8.21%, P=0.028; 3T: VFA/IR-SE=22.87%/5.46%, P=0.001). Among the site-specific protocols, Look-Locker inversion recovery and VFA (2-3 flip angles) protocols showed the best accuracy and repeatability (errors<15%). ConclusionsThe VFA protocols with 2 to 3 flip angles optimized for different applications achieved acceptable balance of extensive spatial coverage, accuracy, and repeatability in T-1 quantification (errors<15%). Further optimization in terms of flip-angle choice for each tissue application, and the use of B-1 correction, are needed to improve the robustness of VFA protocols for T-1 mapping. Magn Reson Med 79:2564-2575, 2018. (c) 2017 International Society for Magnetic Resonance in Medicine.