A microstructural imaging approach to determine morphological neuronaldifferences in adult-onset idiopathic focal cervical dystonia

Maclver, Claire 2024. A microstructural imaging approach to determine morphological neuronaldifferences in adult-onset idiopathic focal cervical dystonia. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Dystonia is a hyperkinetic movement disorder involving involuntary muscle contractions. Adult-onset idiopathic focal cervical dystonia (AOIFCD) affects the neck musculature, causing abnormal posturing, pain and sometimes an associated tremor.Treatment options are limited, reflecting a lack of pathophysiological understanding. Human imaging studies implicate involvement of motor networks, however existing structural MRI studies use measures lacking specificity to underlying neuronal microstructure. This thesis aims to assess structural MRI findings in grey and white matter motor pathways, applying both traditional and more microstructurally relevant approaches. I assessed two distinct cohorts, the first a mixed dystonia cohort (UK Biobank), using imaging acquisitions achievable on a clinical scanner. The second is a prospectively recruited AOIFCD cohort scanned using ultra-strong diffusion gradients with application of more accurate advanced modelling approaches. Standard nonspecific approaches (volumetric and diffusion-based approaches) alongside more advanced modelling (white matter: NODDI and the standard model; grey matter: SANDI and ‘dot’ compartment) were applied. Localised white matter differences were observed in the superior cerebellar peduncles and anterior thalamic radiations in the UK Biobank cohort, predominantly involving lower orientation dispersion. Tremor specific differences included lower anterior thalamic radiation neurite density index and higher striatal grey matter RK. Within the prospectively recruited cohort, lower mid tract intra-axonal signal fraction and higher orientation dispersion were observed in the anterior thalamic radiations, with right hemisphere dominant differences including intra-axonal signal fraction measures (higher mid tract and lower distally) in the striato-premotor and thalamo-premotor tracts in AOIFCD compared to controls. Grey matter differences between cohorts were minimal, with higher right anterior cerebellar AK only seen amongst the tremor subgroup.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Medicine
Date of First Compliant Deposit:	13 September 2024
Last Modified:	13 Sep 2024 10:02
URI:	https://orca.cardiff.ac.uk/id/eprint/172057

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