Purpose: Dynamic contrast enhanced MRI (DCE-MRI) and dynamic susceptibility contrast MRI (DSC-MRI) provide permeability- and perfusion-related parameters, respectively, and are evolving as increasingly common modalities for evaluating a variety of brain cancers. However, acquiring both in one exam requires two separate scans and multiple contrast injections. In this work, we developed an MR MultiTasking-based Dynamic Imaging for Cerebrovascular Evaluation (MT-DICE) technique for simultaneous high-temporal-resolution, distortion-free DCE-MRI and leakage-insensitive DSC-MRI in one scan with a single-dose injection.
Methods: MT-DICE employs a 3D Cartesian acquisition with periodic non-selective saturation recovery (SR) preparations followed by multi-echo FLASH readouts. Image reconstruction is performed based on MR multitasking framework with an SR time dimension and an echo time dimension for dynamic T₁/T₂* quantification, respectively, and a contrast phase dimension for contrast dynamics imaging. DCE- and leakage-insensitive DSC-MRI metrics are computed by tracer kinetic modeling with tracer concentrations derived directly from the dynamic T₁/T₂* values. The technique was tested on 8 healthy subjects and 5 patients with known brain tumors at 3-T with a 7.6-minute scan (1.5×1.5×4.0mm³ spatial resolution, 1.2s temporal resolution). Inversion-recovery TSE and multi-echo GRE were performed in healthy subjects to provide T₁/T₂* references, respectively. Three healthy subjects were returned for a second session for reproducibility assessment.
Results: MT-DICE T₁/T₂* values showed excellent quantitative agreement with references with all intraclass correlation coefficients (ICC) ≥0.85. The permeability and perfusion parameters demonstrated good intersession reproducibility, with the ICCs of vp, Ktrans, CBV, and CBF at 0.822, 0.694, 0.872, and 0.857, respectively. Derived values of the kinetic parameters in all healthy subject and patient cases were within the literature range.
Conclusion: MT-DICE simultaneously quantifies permeability and leakage-insensitive perfusion parameters in a single 7.6-minute scan with a single-dose injection. Such a spatially matched multiparametric evaluation would potentially improve the performance of tumor characterization and treatment response monitoring.