Dynamic Evolution of Infarct Volumes at MRI in Ischemic Stroke Due to Large Vessel Occlusion.

BACKGROUND AND OBJECTIVES: The typical infarct volume trajectories in stroke patients, categorized as slow or fast progressors, remain largely unknown. This study aimed to reveal the characteristic spatiotemporal evolutions of infarct volumes caused by large vessel occlusion (LVO) and show that such growth charts help anticipate clinical outcomes. METHODS: We conducted a secondary analysis from prospectively collected databases (FRAME, 2017-2019; ETIS, 2015-2022). We selected acute MRI data from anterior LVO stroke patients with witnessed onset, which were divided into training and independent validation datasets. In the training dataset, using Gaussian mixture analysis, we classified the patients into 3 growth groups based on their rate of infarct growth (diffusion volume/time-to-imaging). Subsequently, we extrapolated pseudo-longitudinal models of infarct growth for each group and generated sequential frequency maps to highlight the spatial distribution of infarct growth. We used these charts to attribute a growth group to the independent patients from the validation dataset. We compared their 3-month modified Rankin scale (mRS) with the predicted values based on a multivariable regression model from the training dataset that used growth group as an independent variable. RESULTS: We included 804 patients (median age 73.0 years [interquartile range 61.2-82.0 years]; 409 men). The training dataset revealed nonsupervised clustering into 11% (74/703) slow, 62% (437/703) intermediate, and 27% (192/703) fast progressors. Infarct volume evolutions were best fitted with a linear (r = 0.809; p < 0.001), cubic (r = 0.471; p < 0.001), and power (r = 0.63; p < 0.001) function for the slow, intermediate, and fast progressors, respectively. Notably, the deep nuclei and insular cortex were rapidly affected in the intermediate and fast groups with further cortical involvement in the fast group. The variable growth group significantly predicted the 3-month mRS (multivariate odds ratio 0.51; 95% CI 0.37-0.72, p < 0.0001) in the training dataset, yielding a mean area under the receiver operating characteristic curve of 0.78 (95% CI 0.66-0.88) in the independent validation dataset. DISCUSSION: We revealed spatiotemporal archetype dynamic evolutions following LVO stroke according to 3 growth phenotypes called slow, intermediate, and fast progressors, providing insight into anticipating clinical outcome. We expect this could help in designing neuroprotective trials aiming at modulating infarct growth before EVT.

Location specific rupture risk of intracranial aneurysms: case of ophthalmic aneurysms.

BACKGROUND: Aneurysm location is a key element in predicting the rupture risk of an intracranial aneurysm. A common impression suggests that pure ophthalmic aneurysms are under-represented in ruptured intracranial aneurysms (RIAs). The purpose of this study was to specifically evaluate the risk of rupture of ophthalmic aneurysms compared with other aneurysm locations. METHODS: This multicenter study compared the frequency of ophthalmic aneurysms in a prospective cohort of RIAs admitted to 13 neuroradiology centers between January 2021 and March 2021, with a retrospective cohort of patients with unruptured intracranial aneurysms (UIAs) who underwent cerebral angiography at the same neuroradiology centers during the same time period. RESULTS: 604 intracranial aneurysms were included in this study (355 UIAs and 249 RIAs; mean age 57 years (IQR 49-65); women 309/486, 64%). Mean aneurysm size was 6.0 mm (5.3 mm for UIAs, 7.0 mm for RIAs; P<0.0001). Aneurysm shape was irregular for 37% UIAs and 73% RIAs (P<0.0001). Ophthalmic aneurysms frequency was 14.9% of UIAs (second most common aneurysm location) and 1.2% of RIAs (second least common aneurysm location; OR 0.07 (95% CI 0.02 to 0.23), P<0.0001). CONCLUSIONS: Ophthalmic aneurysms seem to have a low risk of rupture compared with other intracranial aneurysm locations. This calls for a re-evaluation of the benefit-risk balance when considering preventive treatment for ophthalmic aneurysms.

Etiologic and prognostic value of external carotid artery thrombus detection during endovascular therapy for anterior circulation proximal occlusions.

BACKGROUND AND PURPOSE: An early understanding of stroke mechanism may improve treatment and outcome in patients presenting with large vessel occlusion stroke (LVOS) treated with mechanical thrombectomy (MT). We aimed to investigate whether spontaneous external carotid artery (ECA) embolism detection during MT is associated with stroke etiology and clinical outcome. METHODS: We retrospectively reviewed our prospectively maintained institutional database including consecutive patients with anterior circulation LVOS treated with MT between January 2015 and August 2020. RESULTS: An ECA embolus was detected in 68 of 1298 patients (5.2%). The kappa coefficient for interobserver agreement was 0.89 (95% confidence interval [CI] 0.82-0.95). ECA embolism was significantly associated with intracranial internal carotid artery (ICA) occlusion (p < 0.001), cardioembolic etiology (p < 0.001) and a lower clot burden score (p < 0.001). Day-1 variation of National Institutes of Health Stroke Scale score (adjusted odds ratio [OR] -2.7, 95% CI -4.9 to 0.3; p = 0.021) and delta Alberta Stroke Program Early Computed Tomography Score (adjusted OR 0.9, 95% CI 0.2 to 1.5; p = 0.004) were worse among patients with ECA emboli. There was no significant difference in 90-day functional outcome between groups (adjusted OR 0.8, 95% CI 0.42 to 1.52; p = 0.50). CONCLUSION: In patients with anterior circulation LVOS treated with MT, ECA embolism was significantly associated with cardioembolic etiology, high thrombus burden and proximal intracranial ICA occlusions. This underexplored angiographic pattern might provide a valuable etiologic clue to the underlying cause of anterior circulation LVOS and may also help determine the appropriate revascularization strategy.