RPS 611a - Neurodegenerative diseases

Purpose:

To investigate cerebral microstructural changes in amyotrophic lateral sclerosis (ALS) using diffusion kurtosis imaging (DKI) for the first time.

Methods and materials:

18 ALS patients and 20 controls were included and underwent DKI scanning. A revised-ALS functional rating scale (ALSFRS-R) was administered to assess disease severity. Disease duration and progression rate were also recorded. Voxel-based analysis was applied to examine the alteration of DKI metrics (i.e. mean(MK)/axial(AK)/radial(RK) kurtosis) and conventional diffusion metrics (i.e. fractional anisotropy and mean/axial/radial diffusivity).

Results:

ALS patients showed MK reductions in grey-matter areas, including the bilateral precentral gyrus, bilateral paracentral lobule, and left anterior cingulate gyrus. They also showed decreased MK values in white matter (WM) in the bilateral precentral gyrus, bilateral corona radiata, bilateral middle corpus callosum, left occipital lobe, and right superior parietal lobule. The spatial distribution of regions with reduced RK was similar to those with decreased MK. No between-group AK difference was found. The correlation analysis revealed significant associations between DKI metrics and clinical assessments such as the ALSFRS-R score and disease duration. Additionally, several WM regions showed between-group differences in conventional diffusion metrics, but the spatial extent was smaller than that with reduced DKI metrics.

Conclusion:

The reduction in DKI metrics indicates decreased microstructural complexity in ALS, involving both motor-related areas and extra-motor regions. DKI measurements can serve as potential biomarkers for assessing disease severity and provide supplementary information to the conventional diffusion in relecting ALS-related WM abnormalities.

Limitations:

The sample size is relatively small.

Ethics committee approval

Approval for this evaluation was obtained from the Research Ethics Committee of Fujian Medical University Union Hospital, China. All of the subjects provided written informed consent.

Funding:

National Natural Science Foundation of China (No. 81501450).

Purpose:

Rapid eye movement sleep behaviour disorder (RBD) is known as a precursor to Parkinson's disease (PD) and identifying a predictor is important to assess PD development from RBD. We aimed to assess the serial putamen changes in a precursor state and determine a predictive image marker for PD development from RBD.

Methods and materials:

8 patients with RBD (RBD group) and 16 patients (PD group) with early PD (Hoehn and Yahr scale: 1-2) underwent dopamine transporter (DAT) imaging and diffusion tensor magnetic resonance imaging (DTI).

The DAT-specific binding ratio (SBR) and the putamen DTI value [mean diffusivity (MD) and fractional anisotropy (FA) values] were calculated.

For each value, the time course in the RBD group and the significance of intergroup differences using a Mann-Whitney’s U test were assessed.

Logit (p) was used to estimate the probability of early PD from RBD in relation to the SBR and the DTI value, and the performance of each value to discriminate early PD from RBD was assessed using receiver operating characteristic (ROC) analysis.

Results:

During the time course of RBD, there were no significant changes in any value. Both the SBR and the FA value were significantly less in the PD group than in the RBD group.

RBD and PD groups can be separated clearly with the SBR and the FA value. The respective areas under the ROC curve (AUCs) for SBR/FA value were 0.95/0.80 and the AUC for logit (p) was 1.00.

Conclusion:

The use of both DAT-SBR and DTI-FA can provide a high performance to discriminate early PD from RBD.

Limitations:

The RBD group underwent a short time follow-up.

Ethics committee approval

Our institutional review board approved this study.

Funding:

Two of co-authors were supported by the Japan Agency for Medical Research and development.