EXPRESS: Perfusion Extent and Hypoperfusion Severity Determine Diaschisis Patterns in Acute Ischemic Stroke: A CT Perfusion Study

BACKGROUND: Diaschisis reflects remote functional suppression following focal ischemia and large-scale network disruption. We investigate the prevalence, overlap, and determinants of multiple diaschisis subtypes using acute CTP. METHODS: We retrospectively analyzed 659 patients with hyperacute large-vessel occlusion stroke. Diaschisis was primarily assessed on CBV maps and classified into Crossed Cerebellar (CCD), Ipsilateral Thalamic (ITD), Ipsilateral Hippocampal (IHD), and CCD+ITD. Tmax-based assessment was exploratory. Multivariable logistic regression evaluated severe hypoperfusion extent (Tmax>6s), hypoperfusion intensity ratio (HIR), and ischemic core volume (CBF<30%). RESULTS: CCD was the most common subtype, followed by ITD and CCD+ITD, whereas IHD was rare. Greater severe hypoperfusion extent was independently associated with CCD, ITD, and CCD+ITD, while higher HIR was additionally associated with ITD, and CCD+ITD. Ischemic core volume was not independently associated with diaschisis. CCD was independently associated with left hemispheric stroke, while combined CCD+ITD was associated with female sex. Exploratory Tmax-based analyses showed broadly similar associations. Subtype overlap suggested involvement of multiple interconnected network nodes. CONCLUSION: Hyperacute diaschisis reflects ischemia-driven network dysfunction primarily related to severe hypoperfusion extent, with hypoperfusion severity contributing to specific subtypes. These findings support CBV-based CTP assessment for investigating large-scale network vulnerability, while Tmax-based may provide complementary information for future diaschisis research.