Altered callosal morphology in post-stroke cognitive impairment

Stroke is the second leading cause of death and cognitive impairment. Post-stroke cognitive impairment (PSCI) is one of the most common sequelae among stroke survivors, yet its underlying neural mechanisms remain largely unclear. The corpus callosum (CC) plays a crucial role in interhemispheric integration and hemispheric segregation, with changes in CC morphology potentially overlapping with the spectrum of PSCI. This study aimed to investigate the morphological changes in the CC and their diagnostic value in PSCI patients. Structural MRI, neurobehavioral, and clinical data were collected from 104 PSCI patients and 54 demographically matched healthy controls. Significant reductions in CC area, circularity, and genu thickness were observed in PSCI patients, with these changes strongly correlating with global cognitive function. Subgroup analysis revealed that CC circularity significantly decreased when lesions were located in the posterior circulation, while both CC area and circularity markedly decreased with anterior circulation lesions. Receiver Operating Characteristic analyses identified the midbody areas of the CC as having high diagnostic value, with area under the curve values of 0.748 and 0.746, respectively. Further validation analyses suggest that the transcallosal fibers in these CC subregions are connected to the premotor, dorsal attention, and frontoparietal system. These findings show that areal CC atrophy in PSCI patients, particularly in regions with transcallosal connections to the premotor cortex and frontoparietal network, parallels global cognitive impairment. This suggests that CC morphology may serve as a potential imaging marker for the diagnosis and prognosis of PSCI.