Compared with asymptomatic middle cerebral artery disease, there was a high and continuous recurrence rate of ischemic events in symptomatic patients, which was even higher than in patients with symptomatic extracranial carotid artery disease.

Background and Purpose-Diffusion-weighted (DW) MRI is a sensitive method that facilitates early stroke pattern identification. There are limited data about the influence of stenosis grade on the development of particular stroke patterns in internal carotid artery (ICA) disease. We therefore investigated the lesion patterns on DW MRI in acute stroke patients with ICA disease. Methods-DW MRI was analyzed in 102 consecutive acute stroke patients with different degrees of ipsilateral ICA disease. Patients were assigned to 1 of 5 observed lesion patterns: (1) territorial ischemia, (2) subcortical ischemia without or (3) with embolus fragmentation, (4) disseminated lesions in distal cortical regions, and (5) multiple lesions in hemodynamic risk zones. In addition, perfusion-weighted (PW) MRI and MR angiography information was included in the assessment. Results-All patterns were observed in the different stages of ICA disease. Half of the patients with high-grade or subtotal stenosis had lesions in hemodynamic risk zones. Territorial stroke occurred in 47.6% of patients with ICA occlusion. Statistical analysis showed a significant relationship between the degree of stenosis and the observed stroke pattern (Pϭ0.001). In 77.8% of patients exhibiting high-grade ICA stenosis, subtotal stenosis, or occlusion, the perfusion lesion was larger than the diffusion lesion (PW/DW mismatch). Conclusions-Although in the individual patient any of the infarct patterns may occur, in statistical terms the incidence of a particular stroke pattern is clearly dependent on the degree of stenosis. Key Words: carotid artery diseases Ⅲ magnetic resonance imaging, diffusion-weighted Ⅲ stroke, acute A therosclerotic narrowing of the extracranial vessels is a well-recognized cause of cerebral ischemia. The annual stroke risk for patients with asymptomatic internal carotid artery (ICA) stenosis amounts to approximately 1% to 2%. 1,2 Both embolic and hemodynamic mechanisms are assumed to be the cause of stroke in ICA disease. 3 Neuroimaging studies have been performed in an attempt to improve the understanding of the underlying stroke mechanism as a basis for the identification of patients at high risk and for the best possible therapeutic rationale. Studies based on CT have suggested that hemodynamically significant stenoses or obstructions of the extracranial ICA may cause hemodynamic changes in the distal regions of the hemispheric blood supply, the so-called border zones between major vascular territories, while embolism from ICA stenosis is believed to disproportionately affect the middle cerebral artery (MCA) stem and distal branches producing territorial infarction, often including the deep lenticulostriate territory. 4 The coexistence of hypoperfusion and arterial embolism in patients with border zone stroke and ICA disease has recently been postulated. 5 Since the concept of border zone ischemia as a cause of stroke in patients with severe ICA stenosis has also been challenged, 6,7 uncertainty still remains regarding the occurrence and me...

Objective We aimed to estimate the incidence of cerebral sinus and venous thrombosis (CVT) within 1 month from first dose administration and the frequency of vaccine‐induced immune thrombotic thrombocytopenia (VITT) as the underlying mechanism after vaccination with BNT162b2, ChAdOx1, and mRNA‐1273, in Germany. Methods A web‐based questionnaire was e‐mailed to all departments of neurology. We requested a report of cases of CVT occurring within 1 month of a COVID‐19 vaccination. Other cerebral events could also be reported. Incidence rates of CVT were calculated by using official statistics of 9 German states. Results A total of 45 CVT cases were reported. In addition, 9 primary ischemic strokes, 4 primary intracerebral hemorrhages, and 4 other neurological events were recorded. Of the CVT patients, 35 (77.8%) were female, and 36 (80.0%) were younger than 60 years. Fifty‐three events were observed after vaccination with ChAdOx1 (85.5%), 9 after BNT162b2 (14.5%) vaccination, and none after mRNA‐1273 vaccination. After 7,126,434 first vaccine doses, the incidence rate of CVT within 1 month from first dose administration was 0.55 (95% confidence interval [CI] = 0.38–0.78) per 100,000 person‐months (which corresponds to a risk of CVT within the first 31 days of 0.55 per 100,000 individuals) for all vaccines and 1.52 (95% CI = 1.00–2.21) for ChAdOx1 (after 2,320,535 ChAdOx1 first doses). The adjusted incidence rate ratio was 9.68 (95% CI = 3.46–34.98) for ChAdOx1 compared to mRNA‐based vaccines and 3.14 (95% CI = 1.22–10.65) for females compared to non‐females. In 26 of 45 patients with CVT (57.8%), VITT was graded highly probable. Interpretation Given an incidence of 0.02 to 0.15 per 100,000 person‐months for CVT in the general population, these findings point toward a higher risk for CVT after ChAdOx1 vaccination, especially for women. ANN NEUROL 2021

Background and Purpose-Reports of ischemic stroke affecting the hippocampus are rare. In this study we used diffusion-weighted MRI (DWI) to characterize patients with posterior circulation stroke involving the hippocampus. Methods-Fifty-seven consecutive acute stroke patients with hippocampal infarct (HI) on DWI were analyzed with regard to clinical features and ischemic lesion patterns. The last 20 of these underwent additional neuropsychological testing of short-term, working, and episodic long-term memory. Results-We found unilateral HI in 54 and bilateral HI in 3 patients. Visual analysis identified 4 patterns of DWI lesion affecting (1) the complete hippocampus (15/60), (2) the lateral (19/60) or (3) dorsal (22/60) parts of the hippocampal body and tail, and (4) circumscribed lesions in the lateral hippocampus (4/60), corresponding well to hippocampal vascular anatomy. In all cases DWI showed further ischemic lesions in the posterior circulation. Symptoms from lesions outside the hippocampus were the common leading clinical signs. Whereas mnestic deficits were prominent in only 11/57 patients, neuropsychological examination in 20 patients showed deficits of verbal episodic long-term memory in left and of nonverbal episodic long-term memory in right HI. Conclusion-Several phenotypic lesion patterns can be distinguished in HI that usually occur as part of multifocal PCA ischemia. A careful neuropsychological examination is necessary to detect resulting memory deficits.