Changes of Myelin Organization in Patients with Alzheimer's Disease Shown by q-Space Myelin Map Imaging

Abstract

Background: Recent studies detected the aberrant myelination of the central nervous system (CNS) in Alzheimer's disease (AD). Here, we compared the change of myelination between patients with AD and controls by a novel magnetic resonance imaging modality, "q-space myelin map (MM) imaging."

Methods: Twenty patients with AD and 18 healthy subjects underwent MM imaging. We compared the MM metric between the 2 groups and examined the relationships between the metric and the clinical symptoms of AD.

Results: AD patients showed a significant reduction of MM metric in the hippocampus, insula, precuneus, and anterior cingulate regions. There was also a significant negative correlation between the duration of illness and the MM metric in the temporoparietal region.

Conclusion: Our findings suggest that MM imaging could be a clinically proper modality to estimate the myelination changes in AD patients.

Keywords: Alzheimer's disease; Magnetic resonance imaging; Myelination; White matter.

Fig. 1

Participant 1: a 55-year-old healthy woman. These images are the samples of the q-space myelin map imaging.

Fig. 2

Aging effect on the myelin map index. There were significant correlations between the age and myelin map index. The background images were “avg152T1” images regarded as the anatomical standard images in the SPM8. The same results were projected on the glass brain. R, right; L, left.

Fig. 3

The morphological brain changes in the patients with Alzheimer's disease. a Compared to the healthy subjects, the patients with Alzheimer's disease showed significant demyelination in the left hippocampus, left insula, bilateral anterior cingulate gyri, and the right precuneus. The same results were projected on the glass brain. b In the patients with Alzheimer's disease, there were significant gray matter volume decreases in the bilateral precuneus regions, anterior cingulate gyri, and prefrontal regions. The background images were “avg152T1” images regarded as the anatomical standard images in the SPM8. The same results were projected on the glass brain. R, right; L, left.

Fig. 4

The relationship between the myelination and the duration of illness in the patients with Alz­heimer's disease. There was a significant negative correlation between the myelin density in the left temporoparietal regions of the patients with Alzheimer's disease and the duration of their illness. The background images were “avg152T1” images regarded as the anatomical standard images in the SPM8. The same results were projected on the glass brain. R, right; L, left.