Personalized pathology maps to quantify diffuse and focal brain damage

Personalized pathology maps to quantify diffuse and focal brain damage

Blog Article

Background and objectives: Quantitative MRI (qMRI) permits the quantification of brain changes compatible with inflammation, degeneration and repair in multiple sclerosis (MS) patients.In this study, we propose a new method to provide personalized maps of tissue alterations and longitudinal brain changes based on different qMRI metrics, which provide complementary information about brain pathology.Methods: We performed baseline and two-years follow-up Basket on (i) 13 relapsing-remitting MS patients and (ii) four healthy controls.

A group consisting of up to 65 healthy controls was used to compute the reference distribution of qMRI metrics in healthy tissue.All subjects underwent 3T MRI examinations including T1, T2, T2* relaxation and Magnetization Transfer Ratio (MTR) imaging.We used a recent partial volume estimation algorithm to estimate the concentration of different brain tissue types on T1 maps; then, we computed a deviation map (z-score map) for each contrast at both time-points.

Finally, we subtracted those deviation maps only for voxels showing a significant difference with healthy tissue in one of the time points, to obtain a difference Gaffer Tape map for each subject.Results and conclusion: Control subjects did not show any significant z-score deviations or longitudinal z-score changes.On the other hand, MS patients showed brain regions with cross-sectional and longitudinal concomitant increase in T1, T2, T2* z-scores and decrease of MTR z-scores, suggesting brain tissue degeneration/loss.

In the lesion periphery, we observed areas with cross-sectional and longitudinal decreased T1/T2 and slight decrease in T2* most likely related to iron accumulation.Moreover, we measured longitudinal decrease in T1, T2 - and to a lesser extent in T2* - as well as a concomitant increase in MTR, suggesting remyelination/repair.In summary, we have developed a method that provides whole-brain personalized maps of cross-sectional and longitudinal changes in MS patients, which are computed in patient space.

These maps may open new perspectives to complement and support radiological evaluation of brain damage for a given patient.Keywords: Multi-parametric MRI, Quantitative MRI, Personalized MRI, Multiple sclerosis, Deviation maps, MRI pathology.