BackgroundSmall subcortical infarcts account for up to 25% of ischaemic strokes. Thalamus is one of the subcortical structures that commonly manifest with lacunar infarcts on MRI of the brain. Studies have shown that thalamus infarction is associated with cognitive decline. However, due to the lack of proper animal models, little is known about the mechanism. We aimed to establish a focal thalamus infarction model, characterise the infarct lesion and assess functional effects.MethodsMale C57BL/6J mice were anaesthetised, and Rose Bengal dye was injected through the tail vein. The right thalamus was illuminated with green laser light by stereotactic implantation of optic fibre. Characteristics of the infarct and lesion evolution were evaluated by histological analysis and 7T MRI at various times. The cognitive and neurological functions were assessed by behavioural tests. Retrograde tracing was performed to analyse neural connections.ResultsAn ischaemic lesion with small vessel occlusion was observed in the thalamus. It became a small circumscribed infarct with reactive astrocytes accumulated in the infarct periphery on day 21. The mice with thalamic infarction demonstrated impaired learning and memory without significant neurological deficits. Retrogradely labelled neurons in the retrosplenial granular cortex were reduced.ConclusionThis study established a mouse model of thalamic lacunar infarction that exhibits cognitive impairment. Neural connection dysfunctions may play a potential role in post-stroke cognitive impairment. This model helps to clarify the pathophysiology of post-stroke cognitive impairment and to develop potential therapies.

Intracranial vessel wall lesions are involved in a variety of neurological diseases. The advanced technique 7T MRI provides greater efficacy in the diagnosis of the pathology changes in the vessel wall and helps to identify potential subtle lesions. The purpose of this literature review was to systematically describe and evaluate the existing literature focusing on the use of 7T MRI in the detection and characterization of intracranial vessel wall lesions and their associated neurological disorders, to highlight the current knowledge gaps, and to formulate a framework to guide future applications and investigations. We systematically reviewed the existing articles up to July 2021, seeking the studies that assessed intracranial vessel wall lesions and their associated neurological disorders using 7T MRI. The literature search provided 12 studies that met the inclusion criteria. The most common intracranial vessel wall lesions were changes related to intracranial atherosclerosis (n = 8) and aneurysms (n = 4), such as intracranial atherosclerosis burden and aneurysm wall enhancement. The associated neurological disorders included aneurysms, ischemic stroke or TIA, small vessel disease, cognitive decline, and extracranial atherosclerosis. No paper studied the use of 7T MRI for investigating vessel wall conditions such as moyamoya disease, small vessel disease, or neurological disorders related to central nervous vasculitis. In conclusion, the novel 7T MRI enables the identification of a wider spectrum of subtle changes and associations. Future research on cerebral vascular diseases other than intracranial atherosclerosis and aneurysms may also benefit from 7T MRI.