Local Diffusion Homogeneity Provides Supplementary Information in T2DM-Related WM Microstructural Abnormality Detection.

Yi Liang,Jiarui Liu,Han Zhang,Xin Tan,Jingxian Chen,Dinggang Shen,Yanting Zheng,Hui Zeng,Chunhong Qin,Shijun Qiu,Xi Leng,Yujie Liu

doi:10.3389/fnins.2019.00063

Abstract

Objectives: We aimed to investigate whether an inter-voxel diffusivity metric (local diffusion homogeneity, LDH), can provide supplementary information to traditional intra-voxel metrics (i.e., fractional anisotropy, FA) in white matter (WM) abnormality detection for type 2 diabetes mellitus (T2DM).Methods: Diffusion tensor imaging was acquired from 34 T2DM patients and 32 healthy controls. Voxel-based group-difference comparisons based on LDH and FA, as well as the association between the diffusion metrics and T2DM risk factors [i.e., body mass index (BMI) and systolic blood pressure (SBP)], were conducted, with age, gender and education level controlled.Results: Compared to the controls, T2DM patients had higher LDH in the pons and left temporal pole, as well as lower FA in the left superior corona radiation (p < 0.05, corrected). In T2DM, there were several overlapping WM areas associated with BMI as revealed by both LDH and FA, including right temporal lobe and left inferior parietal lobe; but the unique areas revealed only by using LDH included left inferior temporal lobe, right supramarginal gyrus, left pre- and post-central gyrus (at the semiovale center), and right superior radiation. Overlapping WM areas that associated with SBP were found with both LDH and FA, including right temporal pole, bilateral orbitofrontal area (rectus gyrus), the media cingulum bundle, and the right cerebellum crus I. However, the unique areas revealed only by LDH included right inferior temporal lobe, right inferior occipital lobe, and splenium of corpus callosum.Conclusion: Inter- and intra-voxel diffusivity metrics may have different sensitivity in the detection of T2DM-related WM abnormality. We suggested that LDH could provide supplementary information and reveal additional underlying brain changes due to diabetes.

Highlights

Type 2 diabetes mellitus, a complex metabolic disorder characterized by increased blood glucose level, affects more than 425 million people, especially those younger than 65 years (International Diabetes Federation, 2017)
local diffusion homogeneity (LDH) at pons, LDH at L temporal pole: LDH values extracted from pons and left temporal pole, respectively; fractional anisotropy (FA) at L corona, FA value extracted from left superior corona radiate
Since greater body mass index (BMI) and systolic blood pressure (SBP) were associated with increased risks of cognitive dysfunctions (Hassing et al, 2004; Alfaro et al, 2018), the inverse brain-clinical associations in our study suggest potential damage of white matter (WM) fiber structure in type 2 diabetes mellitus (T2DM) even before the onset of symptoms

Summary

Introduction

Type 2 diabetes mellitus, a complex metabolic disorder characterized by increased blood glucose level, affects more than 425 million people, especially those younger than 65 years (International Diabetes Federation, 2017). Recent evidence based on in vivo neuroimaging technique showed that the abnormal neural activities were even found in the T2DM subjects who still have normal cognition (Yang et al, 2016; Zhang et al, 2018). To this end, blood-oxygen-level-dependent (BOLD), functional magnetic resonance imaging (fMRI) has been used as a non-invasive brain functional imaging technique in several T2DM brain functional studies (Brundel et al, 2014). The neuropathology and pathophysiology of the early cognitive dysfunctions in T2DM are still not clear (Biessels et al, 2006; Kodl and Seaquist, 2008; Kawamura et al, 2012)

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