MR multitasking-based dynamic imaging for cerebrovascular evaluation (MT-DICE): Simultaneous quantification of permeability and leakage-insensitive perfusion by dynamic T1/T2* mapping
Zhehao Hu, Anthony G. Christodoulou, Nan Wang, Yibin Xie, Mark S. Shiroishi, Wensha Yang, Gabriel Zada, Frances E. Chow, Ashley S. Margol, Benita Tamrazi, Eric L. Chang, Debiao Li, Zhaoyang Fan
Abstract
Purpose
To develop an MR multitasking-based dynamic imaging for cerebrovascular evaluation (MT-DICE) technique for simultaneous quantification of permeability and leakage-insensitive perfusion with a single-dose contrast injection.
Methods
MT-DICE builds on a saturation-recovery (SR) prepared multi-echo fast low-angle shot sequence. K-space is randomly sampled for 7.6 min, with single-dose contrast agent injected 1.5 min into the scan. MR Multitasking is employed to model the data into 6 dimensions, including three spatial dimensions for whole-brain coverage, an SR time dimension and an echo-time dimension for dynamic T1 and T2* quantification, respectively, and a contrast dynamics dimension for capturing contrast kinetics. The derived pixel-wise T1/T2* time series are converted into contrast concentration-time curves for calculation of kinetic metrics. The technique was assessed for its agreement with reference methods in T1 and T2* measurements in 8 healthy subjects and, in 3 of them, inter-session repeatability of permeability and leakage-insensitive perfusion parameters. Its feasibility was also demonstrated in 4 patients with brain tumors.
Results
MT-DICE T1/T2* values of normal gray matter (GM) and white matter (WM) were in excellent agreement with reference values (intraclass correlation coefficients [ICCs] = 0.860/0.962 for GM and 0.925/0.975 for WM). Both permeability and perfusion parameters demonstrated good to excellent intersession agreement with the lowest ICC at 0.694. Contrast kinetic parameters in all healthy subjects and patients were within the literature range.
Conclusion
Based on dynamic T1/T2* mapping, MT-DICE allows for simultaneous quantification of permeability and leakage-insensitive perfusion metrics with a single-dose contrast injection.