Low myelin-related values in the fornix and thalamus of 7 Tesla MRI of major depressive disorder patients

Jeong-Min Shim; Seo-Eun Cho; Chang-Ki Kang; Seung-Gul Kang

doi:10.3389/fnmol.2023.1214738

Low myelin-related values in the fornix and thalamus of 7 Tesla MRI of major depressive disorder patients

Front Mol Neurosci. 2023 Aug 10:16:1214738. doi: 10.3389/fnmol.2023.1214738. eCollection 2023.

Authors

Jeong-Min Shim¹, Seo-Eun Cho², Chang-Ki Kang^{3

4}, Seung-Gul Kang²

Affiliations

¹ Department of Nano Science and Technology, Gachon University Graduate School, Seongnam, Republic of Korea.
² Department of Psychiatry, Gil Medical Center, Gachon University College of Medicine, Incheon, Republic of Korea.
³ Neuroscience Research Institute, Gachon University, Incheon, Republic of Korea.
⁴ Department of Radiological Science, College of Health Science, Gachon University, Incheon, Republic of Korea.

Abstract

Introduction: Abnormalities in myelin are believed to be one of the important causes of major depressive disorder, and it is becoming important to more accurately quantify myelin in in vivo magnetic resonance imaging of major depressive disorder patients. We aimed to investigate the difference in myelin concentration in the white matter and subcortical areas using new quantitative myelin-related maps of high-resolution 7 Tesla (7 T) magnetic resonance imaging between patients with major depressive disorder and healthy controls.

Methods: Myelin-related comparisons of the white matter and nearby subcortical regions were conducted between healthy controls (n = 36) and patients with major depressive disorder (n = 34). Smoothed quantitative ratio (sq-Ratio) myelin-related maps were created using the multi-echo magnetization-prepared two rapid gradient echoes (ME-MP2RAGE) sequence of the T1 and T2* images of 7 T magnetic resonance imaging. Differences in the myelin-related values of the regions of interest between the two groups were analyzed using a two-sample t-test, and multiple comparison corrections were performed using the false discovery rate.

Results: The average sq-Ratio myelin-related values were 2.62% higher in the white matter and 2.26% higher in the subcortical regions of the healthy controls group than in the major depressive disorder group. In the group analysis of the healthy control and major depressive disorder groups, the sq-Ratio myelin-related values were significantly different in the fornix area of the white matter (false discovery rate-corrected p = 0.012). In addition, significant differences were observed in both the left (false discovery rate-corrected p = 0.04) and right thalamus (false discovery rate-corrected p = 0.040) among the subcortical regions.

Discussion: The average sq-ratio myelin-related value and sq-ratio myelin-related values in the fornix of the white matter and both thalami were higher in the healthy controls group than in the major depressive disorder group. We look forward to replicating our findings in other populations using larger sample sizes.

Keywords: 7 T MRI; ME-MP2RAGE; major depressive disorder; myelin-related map; ratio mapping; relaxation times.