Relationship Between Lesion Topology and Clinical Outcome in Anterior Circulation Large Vessel Occlusions

Abstract

Background and purpose Diffusion-weighted imaging (DWI) ASPECTS, a surrogate of infarct volume, predicts outcome in anterior large vessel occlusion (LVO) strokes. We aim to determine whether topological information captured by DWI ASPECTS contributes additional prognostic value. Methods Adults with intracranial ICA, M1 or M2 MCA occlusions who underwent endovascular therapy were included. The primary outcome measure was poor clinical outcome (3-month modified Rankin Scale score 3–6). Prognostic value of the 10 DWI ASPECTS regions in predicting poor outcome was determined by multivariable logistic regression, controlling for final infarct volume, age and laterality. Results 213 patients (mean age 66.1±14.5 years, median NIHSS 15) were included. Inter-rater reliability was good for DWI ASPECTS (Deep regions: Kappa=0.72, Cortical regions: Kappa=0.63). All DWI ASPECTS regions with the exception of the putamen were significant predictors (p<0.05) of poor outcome in univariate analyses. Statistical collinearity among ASPECTS regions was not observed. Using penalized multivariable logistic regression, only M4 (OR=2.82 95%CI 1.39–5.76) and M6 (OR=2.45, 95%CI 1.15–5.3) involvement were associated with poor outcome. M6 involvement independently predicted poor outcome in right hemispheric strokes (OR=5.8, 95%CI 1.9–20.3) whereas M4 (OR=4.3, 95%CI 1.3–15.0) involvement predicted poor outcome in left hemispheric strokes adjusting for infarct volume. Topologic information modestly improved the predictive ability of a prognostic score that incorporates age, infarct volume and hemorrhagic transformation. Conclusions Involvement of the right parieto-occipital (M6) and left superior-frontal (M4) regions impact clinical outcome in anterior LVOs over and above the effect of infarct volume and should be considered during prognostication.

Stroke Location Is an Independent Predictor of Cognitive Outcome

“…In our study, the NIHSS was assessed between 24 and 72 hours, when the deficit was established, reinforcing the correlation with functional outcome. The interest of stroke location assessed by VLSM 15 or other methods, such as simple topology, from Alberta Stroke Program Early CT (ASPECT) score 19 might thus be dampened if initial NIHSS is considered while location is still strongly relevant for cognition that is more difficult to predict only using clinical variables.…”

“…To address this issue, the eloquent regions should be ideally identified on a voxel-wise basis using a voxel-based lesion-symptom mapping (VLSM) technique 16 rather than using predefined, rough, substructures. 11,19 Furthermore, the clinical (age and initial NIHSS) and volumetric information should be combined with stroke location to provide an accurate multimodal model instead of considering location alone. [14][15][16][17][18] Ultimately, a prognostic model has to be validated on a replicating population with the purpose of its application at the individual scale in personalized medicine.…”

Vessel Patency at 24 Hours and Its Relationship With Clinical Outcomes and Infarct Volume in REVASCAT Trial (Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset)

“…The analysis of vessel revascularization at 24 hours followed this methodology, but associations between revascularization at 24 hours with infarct volume and functional outcome were analyzed post hoc. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]) at 24 hours and a higher rate of mortality (52.9% versus 13.8%) compared with those who did undergo follow-up imaging, and no significant differences were found regarding baseline clinical variables between the 2 groups.…”

“…The relationship between posttreatment infarct volume and clinical outcome at 90 days is well established, 11,17 but the fact of mAOL 2 and 3 had equivalent infarct volumes but different probability to achieve favorable outcome may be explained because the location of the brain infarct in an eloquent area and not only the infarct size determine functional outcome after stroke. 18 Another explanation for this observation could be that because of several reasons (delayed infarct growth, infarct being overcalled because of edema, etc), infarct volumes at 24 hours as measured by CT do not reflect accurately enough the true extent of poststroke infarct volume. Patients in the thrombectomy group with an absence of revascularization (mAOL grade 0) at 24 hours showed a nonsignificant higher infarct volume than nonrecanalizers in the medical group, finding that has also been observed in the SWIFT-PRIME study.…”

A Review of Pre-Intervention Prognostic Scores for Early Prognostication and Patient Selection in Endovascular Management of Large Vessel Occlusion Stroke

“…Non-invasive vascular imaging with CT or MR angiography and perfusion imaging are increasingly being performed in an efficient manner to confirm the presence of LVOS prior to ET and estimate clinical and radiographic mismatch and collateral status, especially in patients with low NIHSS scores or those with predominantly subcortical symptoms or absence of hyperdense vessel sign on non-contrast CT. CT ASPECTS is a powerful tool to quantify established hypodensity on the initial non-contrast CT scan; however, its interrater reliability is modest and, unlike core volume that is estimated by perfusion imaging, CT-ASPECTS is not volumetric and its correlation with core volume is poor [38]. However, CT-ASPECTS also captures information on lesion topology by assigning equal weights to areas in the middle cerebral artery territory despite different region volumes [39]. Since pre-ET core volume is a critical determinant of final outcome, patients with large core infarcts are frequently excluded from ET.…”