MR Biomarkers of Degenerative Brain Disorders Derived From Diffusion Imaging

Abstract

The incidence of neurodegenerative diseases has shown an increasing trend. These conditions typically cause progressive functional disability. Identification of robust biomarkers of neurodegenerative diseases is a key imperative to facilitate early identification of the pathological features and to foster a better understanding of the pathogenetic mechanisms of individual diseases. Diffusion tensor imaging (DTI) is the most widely used diffusion MRI technique for assessment of neurodegenerative diseases. The DTI parameters are promising biomarkers for evaluation of microstructural changes; however, some limitations of DTI restrict its wider clinical use. New diffusion MRI techniques, such as diffusion kurtosis imaging (DKI), bi-tensor DTI, and neurite orientation density and dispersion imaging (NODDI) have been demonstrated to provide value addition to DTI for evaluation of neurodegenerative diseases. In this review article, we summarize the key technical aspects and provide an overview of the current state of knowledge regarding the role of DKI, bi-tensor DTI, and NODDI as biomarkers of microstructural changes in representative neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease. Level of Evidence: 5 Technical Efficacy Stage: 2

Fixel-based analysis reveals fiber-specific alterations during the progression of Parkinson’s disease

“…Here we had not found alterations in the nigrostriatal and mesolimbic pathways, which are also common in most previous studies ( Andica et al, 2019 , Atkinson-Clement et al, 2017 ). It is possible that fibers connecting these structures are too thin to be found using routine dMRI acquisition and analysis method.…”

“…In the present study, we aimed to use FBA to investigate white matter fiber alteration in early stage and middle stage PD patients and to explore the association between fiber alterations and clinical symptoms. In several recent meta -analysis studies, decreased FA and/or increased MD in the corpus callosum, cingulum, internal capsule, and temporal lobe fiber tracts were found in PD patients ( Andica et al, 2019 , Atkinson-Clement et al, 2017 ). Therefore, we expect to find similar alterations.…”

Patterns of diffusion kurtosis changes in Parkinson's disease subtypes

“…A clear limitation of a DTI model is the oversimplified assumption that the probability of water diffusion follows the Gaussian distribution. The complexity of the brain tissue leads to serious alterations from this pattern, which is particularly relevant to GM [4,8,9]. Unlike conventional DTI, DKI allows for quantification of the non-Gaussian diffusion as it uses multi-shell acquisition [8].…”

Brain White-Matter Degeneration Due to Aging and Parkinson Disease as Revealed by Double Diffusion Encoding

“…Diffusion MRI (dMRI) is uniquely sensitive to tissue features on the micrometer scale and therefore has been widely used to study neurodegeneration in aging (Madden et al, 2012;Coutu et al, 2014;Billiet et al, 2015;Benitez et al, 2018;Guerreri et al, 2019) and diseases (Goveas et al, 2015;Andica et al, 2019b). In PD, the majority of studies have applied diffusion tensor imaging (DTI) (Basser, 1995) and have consistently reported smaller fractional anisotropy (FA) and greater mean diffusivity (MD) in the white matter of patients than of controls (for a recent review and meta-analysis see Atkinson-Clement et al, 2017).…”