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

Purpose To 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 3 T. Methods A 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. Results For 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 3 T than 1.5 T ( 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; 3 T: 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%). Conclusions The 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.