Large-scale network topography of stroke predicts functional outcome after mechanical thrombectomy.

Abstract

Mechanical thrombectomy effectively restores blood flow in patients with acute ischaemic stroke caused by large vessel occlusion. While mechanical thrombectomy has improved functional outcomes, 35%-60% of patients still experience residual disabilities. Typically, patients are selected for mechanical thrombectomy based on degree of hypoperfusion around the core measured on a vascular atlas. This study had two aims: (i) to evaluate the prognostic value of lesion topography onto functional outcome at 3 months post-mechanical thrombectomy, when the lesion is localized either onto a vascular atlas or large-scale, functional or structural, network atlases; and (2) to examine patterns of post-stroke structural and functional disconnection significantly related to the most common stroke functional outcome scale, i.e. the modified Rankin scale at 3 months post-event. A retrospective analysis was conducted on 70 acute stroke patients who underwent mechanical thrombectomy at the Padua University Hospital (January 2018-June 2022). Inclusion criteria involved first ever ischaemic strokes with anterior circulation large vessel occlusion. Imaging data from sub-acute structural MRI and CT scans were used to estimate indirect structural and functional disconnections. Outcome measures included the modified Rankin Scale at 3 months, with prediction analysis performed using Lasso regression across vascular, grey matter and white matter atlases. Three-month modified Rankin Scale was best predicted using Yeo's functional atlas (R ² = 0.382), followed by the functional white matter atlas (R ² = 0.338); the vascular atlas yielded the weakest prediction (R ² = 0.146). Lesion damage to the corticospinal tract and corona radiata was significantly associated with the modified Rankin Scale. Functional disconnection significantly correlated with disability, particularly in sensorimotor, dorsal attention (DAN) and visual networks. Structural disconnections in the corticospinal tract, corpus callosum, corona radiata, thalamic radiation and left inferior and superior longitudinal fasciculus were also associated with poor functional outcome. This study demonstrates that lesion topography embedded in a network framework provides a more robust prediction of functional outcome. These findings emphasize the importance of understanding network alterations to enhance recovery prediction and optimize treatment strategies for stroke patients. Further research should explore the integration of network-based assessments in clinical practice for evaluating revascularization treatment eligibility.