Multiparametric MRI analysis of patients with amyotrophic lateral sclerosis compared to controls

Introduction: Multiparametric MRI analysis was applied to patients with amyotrophic lateral sclerosis (ALS) in comparison to controls in order to obtain comprehensive information on the affection of cerebral white matter.

Material and Methods: Fractional anisotropy mapping from diffusion tensor imaging (DTI) and intensity based analysis of T1-weighted 3-D MRI were applied to data sets of a samples of nineteen ALS patients (9m/10f, 56±12 years) compared to age and gender matched controls. All data analyses were performed in one common analysis software environment (TIFT – Tensor Imaging and Fiber Tracking).

Fig.1: Left: fiber tracking in the corticospinal tract. Right: coronal slice (y=-23) of DTI analysis (red) and 3-D T1-weighted image analysis (green). Results were superimposed on an averaged 3-D MPRAGE data set.

Results: Complementary analysis and display were performed for WM directionality and structure. Significant WM differences between ALS patients and controls were observed both in the motor system, i.e. the bilateral corticospinal tracts (CST) and in extramotor brain areas, in part correlating with clinical parameters. Furthermore, fiber tracking along the CST showed significant differences between group averaged data sets of controls. The performance of all analyses in TIFT enabled the synopsis of results obtained from various analyses.

Conclusion: The differences between ALS and controls found by the multiparametric approach extended beyond WM areas closely correlated to the motor system and indicated extra-motor involvement especially of frontal and temporal areas. Thus, the performance of all analyses in one software environment offered comprehensive information.