SHORT REPORT

Diffusion tensor imaging and voxel based morphometry study in amyotrophic lateral sclerosis: relationships with motor disability

Lionel Thivard¹, Pierre-François Pradat², Stéphane Lehéricy³, Lucette Lacomblez⁴, Didier Dormont⁵, Jacques Chiras³, Habib Benali⁶, Vincent Meininger²

¹ INSERM U739, Faculté de Médecine Pitié-Salpêtrière, Paris, France
² Fédération des Maladies du Système Nerveux, Hôpital de la Salpêtrière, Paris, France
³ Department of Neuroradiology, Hôpital de la Salpêtrière, Paris, France
⁴ Fédération des Maladies du Système Nerveux and Department of Pharmacology, Hôpital de la Salpêtrière, Paris, France
⁵ Department of Neuroradiology and CNRS UPR640 LENA, Hôpital de la Pitié-Salpêtrière, Paris, France
⁶ INSERM U678, Faculté de Médecine Pitié-Salpêtrière, Paris, France

Correspondence to:
Correspondence to:
Dr Lionel Thivard
INSERM U739, Faculté de Médecine Pitié-Salpêtrière, 105, Boulevard de l’Hôpital, 75013, Paris, France; lionel.thivard{at}psl.ap-hop-paris.fr

The aim of this study was to investigate the extent of cortical and subcortical lesions in amyotrophic lateral sclerosis (ALS) using, in combination, voxel based diffusion tensor imaging (DTI) and voxel based morphometry (VBM). We included 15 patients with definite or probable ALS and 25 healthy volunteers. Patients were assessed using the revised ALS Functional Rating Scale (ALSFRS-R). In patients, reduced fractional anisotropy was found in bilateral corticospinal tracts, the left insula/ventrolateral premotor cortex, the right parietal cortex and the thalamus, which correlated with the ALSFRS-R. Increased mean diffusivity (MD) was found bilaterally in the motor cortex, the ventrolateral premotor cortex/insula, the hippocampal formations and the right superior temporal gyrus, which did not correlate with the ALSFRS-R. VBM analysis showed no changes in white matter but widespread volume decreases in grey matter in several regions exhibiting MD abnormalities. In ALS patients, our results show that subcortical lesions extend beyond the corticospinal tract and are clinically relevant.

Abbreviations: ALS, amyotrophic lateral sclerosis; ALSFRS-R, revised Amyotrophic Lateral Sclerosis Functional Rating Scale; CST, corticospinal tracts; DTI, diffusion tensor imaging; EPI, echo planar images; FA, fractional anisotropy; GM, grey matter; MD, mean diffusivity; VBM, voxel based morphometry; WM, white matter

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