Comparison of NODDI and spherical mean signal for measuring intra-neurite volume fraction

Publication date: Available online 26 November 2018

Source: Magnetic Resonance Imaging

Author(s): Hua Li, Rahul Nikam, Vinay Kandula, Ho Ming Chow, Arabinda K. Choudhary

Abstract

Purpose

Neurite orientation dispersion and density imaging (NODDI) is a clinically feasible approach to measure intra-neurite volume fraction (f_in). However, the sophisticated fitting procedure takes several hours. And the NODDI model relied on several questionable assumptions. Recent analytical work demonstrated that f_in could be simply calculated from the spherical mean signal (MEANS) averaged over all gradient directions with a more solid theoretical foundation. The current study aims to compare NODDI and MEANS for measuring f_in in human brain and investigate the potential of MEANS as a fast approach in clinics.

Methods

NODDI f_in and MEANS f_in were measured and compared on the same dataset. NODDI f_in was obtained using the NODDI MATLAB Toolbox. MEANS f_in is the product of the spherical mean signal and 2bD/π, where D is the intra-neurite intrinsic diffusivity.

Results

NODDI f_in and MEANS f_in maps are similar. The voxel-by-voxel correlation suggests that NODDI f_in and MEANS f_in are approximately equivalent to each other.

Conclusion

MEANS may have potential to serve a fast and simple approach to estimate f_in in clinics.

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