PT  - JOURNAL ARTICLE
AU  - M. Cosottini
AU  - G. Donatelli
AU  - M. Costagli
AU  - E. Caldarazzo Ienco
AU  - D. Frosini
AU  - I. Pesaresi
AU  - L. Biagi
AU  - G. Siciliano
AU  - M. Tosetti
TI  - High-Resolution 7T MR Imaging of the Motor Cortex in Amyotrophic Lateral Sclerosis
AID  - 10.3174/ajnr.A4562
DP  - 2015 Dec 17
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2015/12/17/ajnr.A4562.short
4100  - http://www.ajnr.org/content/early/2015/12/17/ajnr.A4562.full
AB  - BACKGROUND AND PURPOSE: Amyotrophic lateral sclerosis is a progressive motor neuron disorder that involves degeneration of both upper and lower motor neurons. In patients with amyotrophic lateral sclerosis, pathologic studies and ex vivo high-resolution MR imaging at ultra-high field strength revealed the co-localization of iron and activated microglia distributed in the deep layers of the primary motor cortex. The aims of the study were to measure the cortical thickness and evaluate the distribution of iron-related signal changes in the primary motor cortex of patients with amyotrophic lateral sclerosis as possible in vivo biomarkers of upper motor neuron impairment.MATERIALS AND METHODS: Twenty-two patients with definite amyotrophic lateral sclerosis and 14 healthy subjects underwent a high-resolution 2D multiecho gradient-recalled sequence targeted on the primary motor cortex by using a 7T scanner. Image analysis consisted of the visual evaluation and quantitative measurement of signal intensity and cortical thickness of the primary motor cortex in patients and controls. Qualitative and quantitative MR imaging parameters were correlated with electrophysiologic and laboratory data and with clinical scores.RESULTS: Ultra-high field MR imaging revealed atrophy and signal hypointensity in the deep layers of the primary motor cortex of patients with amyotrophic lateral sclerosis with a diagnostic accuracy of 71%. Signal hypointensity of the deep layers of the primary motor cortex correlated with upper motor neuron impairment (r = −0.47; P < .001) and with disease progression rate (r = −0.60; P = .009).CONCLUSIONS: The combined high spatial resolution and sensitivity to paramagnetic substances of 7T MR imaging demonstrate in vivo signal changes of the cerebral motor cortex that resemble the distribution of activated microglia within the cortex of patients with amyotrophic lateral sclerosis. Cortical thinning and signal hypointensity of the deep layers of the primary motor cortex could constitute a marker of upper motor neuron impairment in patients with amyotrophic lateral sclerosis.AbbreviationsALSamyotrophic lateral sclerosisALSFRS-RALS Functional Rating Scale-RevisedDPRdisease progression rateHShealthy subjectsM1primary motor cortexUHFultra-high fieldUMNupper motor neuron