Longitudinal diffusion tensor imaging in amyotrophic lateral sclerosis

Abstract

BackgroundAmyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder, caused by progressive loss of motor neurons. Changes are widespread in the subcortical white matter in ALS. Diffusion tensor imaging (DTI) detects pathological changes in white matter fibres in vivo, based on alterations in the degree (diffusivity, ADC) and directedness (fractional anisotropy, FA) of proton movement.Methods24 patients with ALS and 24 age-matched controls received 1.5T DTI. FA and ADC were analyzed using statistical parametric mapping. In 15 of the 24 ALS patients, a second DTI was obtained after 6 months.ResultsDecreased FA in the corticospinal tract (CST) and frontal areas confirm existing results. With a direct comparison of baseline and follow-up dataset, the progression of upper motor neuron degeneration, reflected in FA decrease, could be captured along the CST and in frontal areas. The involvement of cerebellum in the pathology of ALS, as suspected from functional MRI studies, could be confirmed by a reduced FA (culmen, declive). These structural changes correlated well with disease duration, ALSFRS-R, and physical and executive functions.ConclusionDTI detects changes that are regarded as prominent features of ALS and thus, shows promise in its function as a biomarker. Using the technique herein, we could demonstrate DTI changes at follow-up which correlated well with clinical progression.

Differential Adaptation of Descending Motor Tracts in Musicians

“…Previous studies comparing musicians with nonmusicians yielded contradictory results with regard to FA values in corticospinal motor tracts, and none of the studies related diffusivity measures to motor performance measures (Schmithorst and Wilke 2002;Bengtsson et al 2005;Han et al 2009;Imfeld et al 2009). Studies examining neural effects of long-term instrumental music practice have been complemented by studies showing white matter plasticity in response to the acquisition of other nonmusical sensorimotor skills (Scholz et al 2009;Hanggi et al 2010;Landi et al 2011) as well as in response to recovery from neurological disorders (Schlaug et al 2009;Wrigley et al 2009;Lindenberg et al 2010;Granziera et al 2012;Keil et al 2012;Zipse et al 2012) or neural effects of immobilization (Langer et al 2012). …”

Measuring the progression of upper motor neuron disease using diffusion MRI and its correlation with Clinical phenotype

“…Previous DTI studies using an ROI method showed a bilateral reduction in FA along the CST (Jacob, Finsterbusch et al 2003) while other studies found changes in CST to be confined to the right hemisphere (Zhang, Schuff et al 2011). The changes in motor pathways over time are consistent with the known atrophy in ALS (Jacob, Finsterbusch et al 2003, Keil, Prell et al 2012). …”

“…MRI gives an insight in the understanding of disease pathology and the possible progression of disease to other body regions (Keil, Prell et al 2012). Since MRI is a non-invasive imaging technique, it has been extensively applied in neuroscience and neurological diseases and has the potential to be a useful biomarker for progression of ALS.…”

“…However, the few longitudinal DTI studies of ALS have small numbers of subjects and inconsistent findings , Zhang, Schuff et al 2011, Keil, Prell et al 2012. Some have reported the progression of ALS by demonstrating decreasing FA over time along the corticospinal tract (CST) (Sage, Peeters et al 2007).…”

“…In contrast to cross-sectional studies, longitudinal DTI studies of ALS have shown conflicting findings (Blain, Williams et al 2007, Ajroud-Driss, Mansour et al 2012, Keil, Prell et al 2012, Verstraete, Walhout et al 2012. Thus, it is yet unclear whether DTI is sensitive to changes in CST over time.…”