Diffusion tensor imaging in Parkinson's disease: Review and meta-analysis

Abstract

BackgroundNeuroimaging studies help us better understand the pathophysiology and symptoms of Parkinson's disease (PD). In several of these studies, diffusion tensor imaging (DTI) was used to investigate structural changes in cerebral tissue. Although data have been provided as regards to specific brain areas, a whole brain meta-analysis is still missing.MethodsWe compiled 39 studies in this meta-analysis: 14 used fractional anisotropy (FA), 1 used mean diffusivity (MD), and 24 used both indicators. These studies comprised 1855 individuals, 1087 with PD and 768 healthy controls. Regions of interest were classified anatomically (subcortical structures; white matter; cortical areas; cerebellum). Our statistical analysis considered the disease effect size (DES) as the main variable; the heterogeneity index (I2) and Pearson's correlations between the DES and co-variables (demographic, clinical and MRI parameters) were also calculated.ResultsOur results showed that FA-DES and MD-DES were able to distinguish between patients and healthy controls. Significant differences, indicating degenerations, were observed within the substantia nigra, the corpus callosum, and the cingulate and temporal cortices. Moreover, some findings (particularly in the corticospinal tract) suggested opposite brain changes associated with PD. In addition, our results demonstrated that MD-DES was particularly sensitive to clinical and MRI parameters, such as the number of DTI directions and the echo time within white matter.ConclusionsDespite some limitations, DTI appears as a sensitive method to study PD pathophysiology and severity. The association of DTI with other MRI methods should also be considered and could benefit the study of brain degenerations in PD.

A metabolic profile of polyamines in parkinson disease: A promising biomarker

“…As shown in Table 5, no significant differences were observed for any clinical characteristics and polyamine metabolite levels between PD patients and PD patients with DTI. 35 Spearman rank correlation test also revealed that mean FA values for significant clusters in PD patients correlated positively with DiAcSpd (r = 0.63, p = 0.003). 34 Accordingly, TBSS analysis detected a significant positive correlation between DiAcSpd and FA in an extensive white matter area in the brain of PD patients after normalization of LED and age (see Fig 2I, J; p < 0.05, familywise error-corrected; Peak Montreal Neurological Institute method x, y, z: 77, 90, 110; t max = 7.06; r max = 0.70; voxels = 45,836).…”

Regional and network properties of white matter function in Parkinson's disease

“…Diffusion tensor imaging (DTI) is a powerful tool to investigate microstructural alterations to the human brain in vivo. In PD, this technique has been combined with voxel‐ or region‐of‐interest (ROI)‐wise (Atkinson‐Clement, Pinto, Eusebio, & Coulon, ; Schwarz et al, ), and graph‐theoretical analyses (Aarabi et al, ; Li et al, ; Nigro et al, ; Pereira et al, ). Tract‐based spatial statistics (TBSS) is a voxel‐wise method, specifically developed to minimize the methodological pitfalls caused by misalignment and misregistration in conventional voxel‐based analyses (Smith et al, ).…”

Neuroimaging abnormalities in individuals exhibiting Parkinson's disease risk markers

“…DTI in the SN was shown to be able to differentiate between PD at an early stage and healthy controls indicating that this neuroimaging technique may serve as a noninvasive early imaging marker for PD . Two recent meta‐analyses confirmed a notable effect size with lower fractional anisotropy (FA) in the SN of patients with PD . Microstructural changes on DTI may, however, also be seen in other brain regions depending on the underlying PD phenotype.…”

“…19,20 Two recent meta-analyses confirmed a notable effect size with lower fractional anisotropy (FA) in the SN of patients with PD. 21,22 Microstructural changes on DTI may, however, also be seen in other brain regions 22 depending on the underlying PD phenotype. Patients with freezing of gait, for example, display diffuse white matter abnormalities that involve several cortico-cortical, striato-frontal, and cerebello-pontine connections.…”