3D MR fingerprinting for dynamic contrast‐enhanced imaging of whole mouse brain

Abstract

AbstractPurposeQuantitative MRI enables direct quantification of contrast agent concentrations in contrast‐enhanced scans. However, the lengthy scan times required by conventional methods are inadequate for tracking contrast agent transport dynamically in mouse brain. We developed a 3D MR fingerprinting (MRF) method for simultaneous T1 and T2 mapping across the whole mouse brain with 4.3‐min temporal resolution.MethodWe designed a 3D MRF sequence with variable acquisition segment lengths and magnetization preparations on a 9.4T preclinical MRI scanner. Model‐based reconstruction approaches were employed to improve the accuracy and speed of MRF acquisition. The method's accuracy for T1 and T2 measurements was validated in vitro, while its repeatability of T1 and T2 measurements was evaluated in vivo (n = 3). The utility of the 3D MRF sequence for dynamic tracking of intracisternally infused gadolinium‐diethylenetriamine pentaacetic acid (Gd‐DTPA) in the whole mouse brain was demonstrated (n = 5).ResultsPhantom studies confirmed accurate T1 and T2 measurements by 3D MRF with an undersampling factor of up to 48. Dynamic contrast‐enhanced MRF scans achieved a spatial resolution of 192 × 192 × 500 μm3 and a temporal resolution of 4.3 min, allowing for the analysis and comparison of dynamic changes in concentration and transport kinetics of intracisternally infused Gd‐DTPA across brain regions. The sequence also enabled highly repeatable, high‐resolution T1 and T2 mapping of the whole mouse brain (192 × 192 × 250 μm3) in 30 min.ConclusionWe present the first dynamic and multi‐parametric approach for quantitatively tracking contrast agent transport in the mouse brain using 3D MRF.