Simultaneous perfusion, diffusion, T₂ *, and T₁ mapping with MR fingerprinting

Quantitative mapping of brain perfusion, diffusion, T₂ *, and T₁ has important applications in cerebrovascular diseases. At present, these sequences are performed separately. This study aims to develop a novel MRI technique to simultaneously estimate these parameters.

This sequence to measure perfusion, diffusion, T₂ *, and T₁ mapping with magnetic resonance fingerprinting (MRF) was based on a previously reported MRF-arterial spin labeling (ASL) sequence, but the acquisition module was modified to include different TEs and presence/absence of bipolar diffusion-weighting gradients. We compared parameters derived from the proposed method to those derived from reference methods (i.e., separate sequences of MRF-ASL, conventional spin-echo DWI, and T₂ * mapping). Test-retest repeatability and initial clinical application in two patients with stroke were evaluated.

The scan time of our proposed method was 24% shorter than the sum of the reference methods. Parametric maps obtained from the proposed method revealed excellent image quality. Their quantitative values were strongly correlated with those from reference methods and were generally in agreement with values reported in the literature. Repeatability assessment revealed that ADC, T₂ *, T₁ , and B₁ ⁺ estimation was highly reliable, with voxelwise coefficient of variation (CoV) <5%. The CoV for arterial transit time and cerebral blood flow was 16% ± 3% and 25% ± 9%, respectively. The results from the two patients with stroke demonstrated that parametric maps derived from the proposed method can detect both ischemic and hemorrhagic stroke.

The proposed method is a promising technique for multi-parametric mapping and has potential use in patients with stroke.