MRI data link lacunar stroke to artery widening

MRI data suggest that some lacunar strokes may be linked to widening of brain arteries rather than large-artery blockages, according to research published in Circulation.

The study examined cranial arterial stenosis and dolichoectasia, a widening or elongation of arteries, in patients with prior lacunar or mild nonlacunar stroke. Researchers evaluated how these vascular features related to stroke subtype, cerebral small-vessel disease markers, new infarcts, and clinical outcomes.

Lacunar strokes account for about 20% to 30% of ischemic strokes and have traditionally been linked to small vessel blockage. The new findings challenge the idea that fatty narrowing of larger arteries is a main driver of this subtype, according to the University of Edinburgh.

Researchers studied 229 patients who had experienced either lacunar or mild nonlacunar stroke. Participants underwent clinical and cognitive assessments, as well as brain MRI at the time of stroke diagnosis and again 1 year later, allowing the team to track small-vessel disease markers and new areas of brain injury.

Large-artery stenosis was present in 20.5% of participants, while dolichoectasia was present in 15.7%, according to the study summary. Large-artery stenosis was associated with nonlacunar stroke, but not with lacunar stroke or cerebral small-vessel disease.

Arterial widening showed the opposite pattern. Patients with basilar artery dolichoectasia had 4.7-fold higher odds of lacunar stroke and 2.6-fold higher odds of cerebral small-vessel disease, News-Medical reported from the study. Incident infarcts were also more likely and were mainly subcortical.

White matter hyperintensities progressed more over 1 year in patients with arterial widening. Similar associations were observed for wider intracranial carotid and middle cerebral arteries, supporting the link between widened arteries and small-vessel disease burden.

“This study provides strong evidence that lacunar stroke is not caused by fatty blockage of larger arteries, but by disease of the small vessels within the brain itself,” said Joanna Wardlaw, MD, professor of applied neuroimaging at the University of Edinburgh.

The findings may help explain why conventional treatments such as antiplatelet drugs are not always effective in lacunar stroke. Wardlaw said recognizing the distinction is important because it points to the need for therapies targeting underlying microvascular damage.

The authors concluded that cerebral small-vessel disease, including lacunar stroke, was unrelated to large-artery stenosis but strongly associated with dolichoectasia and wider arteries. They said mechanism-specific diagnostic and therapeutic strategies are needed.

Further research will be needed to clarify how arterial widening contributes to small-vessel injury and whether MRI-based vascular markers can help guide prevention or treatment decisions in patients at risk of lacunar stroke.