Tensor-valued diffusion MRI in under 3 minutes: An initial survey of microscopic anisotropy and tissue heterogeneity in intracranial tumors

Abstract

Purpose: To evaluate the feasibility of a 3-minute b-tensor encoding protocol for diffusion MRI-based assessment of the microscopic anisotropy and tissue heterogeneity in a wide range of intracranial tumors. Methods: B-tensor encoding was performed in 42 patients with intracranial tumors (gliomas, meningiomas, adenomas, metastases). Microscopic anisotropy and tissue heterogeneity were evaluated by estimating the anisotropic kurtosis ($M{K}_A$) and isotropic kurtosis ($M{K}_I$), respectively. An extensive imaging protocol was compared with a faster 3-minute protocol. Results: The fast imaging protocol yielded parameters with characteristics in terms of bias and precision similar to the full protocol. Glioblastomas had lower microscopic anisotropy than meningiomas $(M{K}_A=0.29\pm 0.06$ versus $0.45\pm 0.08,p=0.003)$. Metastases had higher tissue heterogeneity $(M{K}_I=0.57\pm 0.07)$ than both the glioblastomas $(0.44\pm 0.06,p<0.001)$ and meningiomas $(0.46\pm 0.06,p=0.03)$. Conclusion: Evaluation of the microscopic anisotropy and tissue heterogeneity in intracranial tumor patients is feasible in clinically relevant times frames.

Submitted to Magnetic Resonance in Medicine