Sex differences in stroke lesion patterns may explain the higher stroke severity observed in women compared to men.

A US-led international study used MRI to analyse lesion patterns in 555 men and women presenting with acute ischaemic stroke. Their findings were validated in a further 503 patients from an independent cohort.

The study, published in Nature Communications, found many parameters including acute stroke lesion volume and white matter hyperintensity lesion volume did not differ between men and women.

In both men and women, subcortical lesions affecting gray matter regions and white matter tracts explained higher NIHSS based stroke severity.

“Similarly, cortical presumptive bilateral motor and left-lateralised language regions (e.g., especially bilateral precentral and postcentral gyri, left-sided inferior frontal and superior, middle temporal gyri) also explained higher stroke severity,” the study said.

However, “In difference to men, women featured more widespread and also more pronounced lesion pattern, including a greater range of cortical regions contributing to stroke severity, e.g., the left superior, middle and inferior temporal gyrus, left angular gyrus and lateral occipital cortex, lingual gyrus, as well as precuneus and parahippocampal cortex gyrus.”

The study also provided some insight into the possible impact of sex hormones on the brain – noting that female-specific effects were noticeably more pronounced with advanced age.

“All of the female-specific lesion atom effects, as observed in the main analysis, disappeared in the analysis of all men and women below the age of 52 years,” it said.

The study said their findings likely had clinical implications but more research was required on the impact of hormone replacement therapy after menopause, oral contraceptives prior to menopause and surgical interventions such as hysterectomies and oophorectomies,

“Overall, an effective step toward tailored medical stroke care may lie in more sex-aware acute treatment decisions. Sex-specific guidelines on stroke prevention could be complemented by sex-specific guidelines on acute treatment decisions, enhancing sex-sensitive stroke care and ultimately increasing the benefit for both men and women,” it concluded.