Objective In the study, we utilized soma and neurite density imaging (SANDI) to investigate stroke-free patients with unilateral middle cerebral artery (MCA) occlusion, with the goal of analyzing gray matter damage in both affected and contralateral hemispheres. Materials and methods The study involved 59 patients with unilateral MCA occlusion and 35 control subjects. All participants underwent three-dimensional T1-weighted imaging and SANDI examination. Model fitting of SANDI data generated maps of the following parameters: soma signal fraction (fSoma), neurite signal fraction (fNeurite), extracellular space signal fraction (fExtra), and apparent soma size (RSoma). A comprehensive voxel-based analysis was conducted, employing a voxel-wise general linear model, to compare whole-brain RSoma, fSoma, fExtra and fNeurite between patients with unilateral MCA occlusion and the controls. Results Patients with unilateral MCA occlusion demonstrate significantly reduced fSoma and fNeurite, and increased fExtra in some regions of bilateral hemispheres compared to the controls. Right-sided MCA occlusion was associated with widespread bilateral microstructural damage involving the frontal, parietal, temporal, occipital, and limbic cortices, subcortical regions, as well as the hippocampus and parahippocampal gyrus. In contrast, left-sided MCA occlusion was characterized by left hemisphere-predominant damage, with more focal involvement of frontal, parietal, and contralateral occipital regions. Conclusion In unilateral MCA occlusion patients with identified abnormalities, the affected brain regions encompass the sensorimotor integration system, language system, limbic-emotional and memory system, subcortical gray matter, and visual processing system. Importantly, the right-sided MCA occlusion patients often have damage to the hippocampus and parahippocampal gyrus, leading to cognitive deficits. Key Points <Emphasis Type="BoldItalic">Question</Emphasis> For asymptomatic stroke-free patients with chronic unilateral MCA occlusion, is microstructural neuronal damage present and detectable by soma and neurite density imaging? <Emphasis Type="BoldItalic">Findings</Emphasis> Soma and neurite density imaging detect reduced fSoma/fNeurite and elevated fExtra in MCA occlusion regions, with worse damage in right-sided cases. <Emphasis Type="BoldItalic">Clinical relevance</Emphasis> This study enables early detection of invisible neuronal damage, alerts to cognitive risks (especially in right MCA occlusion), and provides a basis for targeted clinical interventions. Graphical Abstract

Invisible neuronal damage in stroke-free, asymptomatic chronic middle cerebral artery occlusion: evidence from soma and neurite density imaging

期刊论文
发表日期：

2026年4月18日

查看全文

Zhenghua Liu,
Xinghua Wan,
Yu Xiao

摘要

Objective

In the study, we utilized soma and neurite density imaging (SANDI) to investigate stroke-free patients with unilateral middle cerebral artery (MCA) occlusion, with the goal of analyzing gray matter damage in both affected and contralateral hemispheres.

Materials and methods

The study involved 59 patients with unilateral MCA occlusion and 35 control subjects. All participants underwent three-dimensional T1-weighted imaging and SANDI examination. Model fitting of SANDI data generated maps of the following parameters: soma signal fraction (f_Soma), neurite signal fraction (f_Neurite), extracellular space signal fraction (f_Extra), and apparent soma size (R_Soma). A comprehensive voxel-based analysis was conducted, employing a voxel-wise general linear model, to compare whole-brain R_Soma, f_Soma, f_Extra and f_Neurite between patients with unilateral MCA occlusion and the controls.

Results

Patients with unilateral MCA occlusion demonstrate significantly reduced f_Soma and f_Neurite, and increased f_Extra in some regions of bilateral hemispheres compared to the controls. Right-sided MCA occlusion was associated with widespread bilateral microstructural damage involving the frontal, parietal, temporal, occipital, and limbic cortices, subcortical regions, as well as the hippocampus and parahippocampal gyrus. In contrast, left-sided MCA occlusion was characterized by left hemisphere-predominant damage, with more focal involvement of frontal, parietal, and contralateral occipital regions.

Conclusion

In unilateral MCA occlusion patients with identified abnormalities, the affected brain regions encompass the sensorimotor integration system, language system, limbic-emotional and memory system, subcortical gray matter, and visual processing system. Importantly, the right-sided MCA occlusion patients often have damage to the hippocampus and parahippocampal gyrus, leading to cognitive deficits.

Key Points

Question For asymptomatic stroke-free patients with chronic unilateral MCA occlusion, is microstructural neuronal damage present and detectable by soma and neurite density imaging?

Findings Soma and neurite density imaging detect reduced f_Soma/f_Neurite and elevated f_Extra in MCA occlusion regions, with worse damage in right-sided cases.

Clinical relevance This study enables early detection of invisible neuronal damage, alerts to cognitive risks (especially in right MCA occlusion), and provides a basis for targeted clinical interventions.

Graphical Abstract