Investigating Brain Microstructural Alterations in Type 1 and Type 2 Diabetes Using Diffusion Tensor Imaging: A Systematic Review

Abstract

Type 1 and type 2 diabetes mellitus have an impact on the microstructural environment and cognitive functions of the brain due to its microvascular/macrovascular complications. Conventional Magnetic Resonance Imaging (MRI) techniques can allow detection of brain volume reduction in people with diabetes. However, conventional MRI is insufficiently sensitive to quantify microstructural changes. Diffusion Tensor Imaging (DTI) has been used as a sensitive MRI-based technique for quantifying and assessing brain microstructural abnormalities in patients with diabetes. This systematic review aims to summarise the original research literature using DTI to quantify microstructural alterations in diabetes and the relation of such changes to cognitive status and metabolic profile. A total of thirty-eight published studies that demonstrate the impact of diabetes mellitus on brain microstructure using DTI are included, and these demonstrate that both type 1 diabetes mellitus and type 2 diabetes mellitus may affect cognitive abilities due to the alterations in brain microstructures.

White Matter Microstructural Alteration in Type 2 Diabetes: A Combined UK Biobank Study of Diffusion Tensor Imaging and Neurite Orientation Dispersion and Density Imaging

“…In T2DM participants, WM tracts and fibres mostly show reduced FA and ICVF, and increased MD, AD, RD, ODI, and IsoVF, as presented in supplementary Table 5. Reduced anisotropy and increased diffusivity reflected by reduced FA and higher MD confirm widespread microstructural alterations and broadly agree with previous DTI studies (see the previous reviews 4,10,11 ). Moreover, the results revealed that the elevation of AD and RD in participants with T2DM might lead to changes in FA and MD, as AD is linked to axonal integrity and RD is linked to myelin abnormalities.…”

“…It impacted approximately 462 million people in 2017, accounting for 6.28% of the worldwide population (4.4% of those aged 15-49 years, 15% of those aged 50-69 years, and 22% of those aged 70+), or a prevalence rate of 6059 cases per 100,000 2 . T2DM results in microvascular and macrovascular complications 3 , leading to microvascular impairments, generally recognised as risk factors for general brain atrophy, microstructural alterations, and cognitive impairment [4][5][6] . Using advanced neuroimaging techniques, researchers have recently focused on understanding the link between T2DM and microstructural abnormalities in the brain.…”

“…Advanced magnetic resonance imaging (MRI) techniques such as Diffusion tensor imaging (DTI) have been widely used to explore microstructural changes in the brain, and it has been adopted in several investigations to identify global/local network abnormalities and microstructural changes in WM [7][8][9] . WM tracts microstructurally affected by T2DM as detected by DTI include the corpus callosum, corona radiata, cingulum, internal/external capsules, fornix, uncinate fasciculus, and corticospinal tracts 4,10,11 . DTI is based on a single compartment Gaussian diffusion model of brain microstructure with anisotropic water diffusion 12 .…”

Tractography in Type 2 Diabetes Mellitus With Subjective Memory Complaints: A Diffusion Tensor Imaging Study

“…Compared with traditional structural MRI, DTI seems to be a more sensitive biomarker of cognitive decline caused by aging and axial diffusivity (AD; Schiavone et al, 2009 ; Zhuang et al, 2012 ). Relevant studies have shown that differential brain structural abnormalities between T2DM and healthy control (HC) may reflect pathological mechanisms underlying the effect of blood glucose fluctuation to the brain ( Moulton et al, 2015 ; Alotaibi et al, 2021 ). Abnormalities in specific WM tracts can lead to disruption in information transfer and interruption of pathways within important brain regions ( Xie et al, 2017 ; Sundar et al, 2019 ).…”

Abnormalities of Brain White Matter in Type 2 Diabetes Mellitus: A Meta-Analysis of Diffusion Tensor Imaging

“…Differences in the results of these studies might be due to the limited sample sizes, different acquisition parameters, and analysis methods. Several systematic reviews have summarized the brain microstructural alterations in T2DM using DTI, which suggests the detrimental effects of T2DM on cognitive functions that might be associated with the alterations in brain microstructure (Sanjari Moghaddam et al, 2019;Alotaibi et al, 2021). Although the specific abnormal regions of white matter in T2DM were summarized in the systematic reviews, the locations and sizes of the alterations were not reported.…”