Assessment of MR blood-oxygen-level-dependent (BOLD) cerebrovascular reactivity under general anesthesia in children with moyamoya.

BACKGROUND: Moyamoya is a progressive, non-atherosclerotic cerebral arteriopathy that may present in childhood and currently has no cure. Early diagnosis is critical to prevent a lifelong risk of neurological morbidity. Blood-oxygen-level-dependent (BOLD) MRI cerebrovascular reactivity (CVR) imaging provides a non-invasive, in vivo measure of autoregulatory capacity and cerebrovascular reserve. However, non-compliant or younger children require general anesthesia to achieve BOLD-CVR imaging. OBJECTIVE: To determine the same-day repeatability of BOLD-CVR imaging under general anesthesia in children with moyamoya. MATERIALS AND METHODS: Twenty-eight examination pairs were included (mean patient age = 7.3 ± 4.0 years). Positive and negatively reacting voxels were averaged over signals and counted over brain tissue and vascular territory. The intraclass correlation coefficient (ICC), Wilcoxon signed-rank test, and Bland-Altman plots were used to assess the variability between the scans. RESULTS: There was excellent-to-good (≥ 0.59) within-day repeatability in 18 out of 28 paired studies (64.3%). Wilcoxon signed-rank tests demonstrated no significant difference in the grey and white matter CVR estimates, between repeat scans (all p-values > 0.05). Bland-Altman plots of differences in mean magnitude of positive and negative and fractional positive and negative CVR estimates illustrated a reasonable degree of agreement between repeat scans and no systematic bias. CONCLUSION: BOLD-CVR imaging provides repeatable assessment of cerebrovascular reserve in children with moyamoya imaged under general anesthesia.

Fronto-Parietal and White Matter Haemodynamics Predict Cognitive Outcome in Children with Moyamoya Independent of Stroke.

Moyamoya disease is a major arteriopathy characterised by progressive steno-occlusion of the arteries of the circle of Willis. Studies in adults with moyamoya suggest an association between abnormal fronto-parietal and white matter regional haemodynamics and cognitive impairments, even in the absence of focal infarction. However, these associations have not been investigated in children with moyamoya. We examined the relationship between regional haemodynamics and ratings of intellectual ability and executive function, using hypercapnic challenge blood oxygen level-dependent magnetic resonance imaging of cerebrovascular reactivity in a consecutive cohort of children with confirmed moyamoya. Thirty children were included in the final analysis (mean age: 12.55 ± 3.03 years, 17 females, 15 idiopathic moyamoya and 15 syndromic moyamoya). Frontal haemodynamics were abnormal in all regardless of stroke history and comorbidity, but occipital lobe haemodynamics were also abnormal in children with syndromic moyamoya. Executive function deficits were noted in both idiopathic and syndromic moyamoya, whereas intellectual ability was impaired in syndromic moyamoya, even in the absence of stroke. Analysis of the relative effect of regional abnormal haemodynamics on cognitive outcomes demonstrated that executive dysfunction was predominantly explained by right parietal and white matter haemodynamics independent of stroke and comorbidity, while posterior circulation haemodynamics predicted intellectual ability. These results suggest that parietal and posterior haemodynamics play a compensatory role in overcoming frontal vulnerability and cognitive impairment.

Childhood arterial ischemic stroke due to mineralizing angiopathy: an 18-year single-center experience.

Mineralizing angiopathy is a unique, age-specific stroke syndrome characterized by basal ganglia infarction and lenticulostriate calcification after minor head injury in early childhood. There is limited understanding of the pathophysiology, course, and clinical outcome of this syndrome. We describe the clinical and radiographical phenotype of a single-center, consecutively enrolled cohort of children with mineralizing angiopathy from January 2002 to January 2020 and provide a comparative analysis to previously published literature. Fourteen children were identified. Previously unreported findings include: stroke onset in eight children older than 18 months; presence of basal ganglia hemorrhage in four; multifocal basal ganglia infarcts in three; presence of additional non-basal ganglia calcifications in three; and presence of thrombophilia in one. Seven children had moderate-to-severe neurological deficits. There was no symptomatic stroke recurrence (mean follow-up 3y 7mo, SD 1y 7mo). Our expanded phenotype highlights distinct characteristics of mineralizing angiopathy in children and has the potential to inform future research. What this paper adds Children with mineralizing angiopathy are often misdiagnosed as having a limb fracture despite normal x-rays. A magnetic resonance imaging-only approach may miss this entity. Non-contrast computed tomography, in addition to MRI is recommended to identify calcifications in idiopathic arterial ischemic stroke. Most children have moderate-to-severe neurological sequela.

Distinct Clinical and Radiographic Phenotypes in Pediatric Patients With Moyamoya.

BACKGROUND: Given the expanding evidence of clinico-radiological differences between moyamoya disease (MMD) and moyamoya syndrome (MMS), we compared the clinical and radiographic features of childhood MMD and MMS to identify predictors of ischemic event recurrence. METHODS: We reviewed a pediatric moyamoya cohort followed between 2003 and 2019. Clinical and radiographic characteristics at diagnosis and follow-up were abstracted. Comparisons between MMD and MMS as well as between MMD and two MMS subgroups (neurofibromatosis [MMS-NF1] and sickle cell disease [MMS-SCD]) were performed. RESULTS: A total of 111 patients were identified. Patients with MMD presented commonly with transient ischemic attacks (TIAs) (35 % MMD versus 13% MMS-NF1 versus 9.5% MMS-SCD; P = 0.047). Symptomatic stroke presentation (MMD 37% versus MMS-NF1 4% versus 33%; P = 0.0147) and bilateral disease at diagnosis (MMD 73% versus MMS-NF1 22 % versus MMS-SCD 67%; P = 0.0002) were uncommon in MMS-NF1. TIA recurrence was common in MMD (hazard ratio 2.86; P = 0.001). The ivy sign was absent on neuroimaging in a majority of patients with MMS-SCD (MMD 67% versus MMS-NF1 52% versus MMS-SCD 9.5%; P = 0.0002). Predictors of poor motor outcome included early age at diagnosis (odds ratio [OR] 8.45; P = 0.0014), symptomatic stroke presentation (OR 6.6; P = 0.019), and advanced Suzuki stage (OR 3.59; P = 0.019). CONCLUSIONS: Moyamoya exhibits different phenotypes based on underlying etiologies. Frequent TIAs is a common phenotype of MMD and symptomatic stroke presentation a common feature of MMD and MMS-SCD, whereas unilateral disease and low infarct burden are common in MMS-NF1. In addition, absence of ivy sign is a common phenotype in MMS-SCD.

Swallowing, Oral Motor, Motor Speech, and Language Impairments Following Acute Pediatric Ischemic Stroke.

BACKGROUND AND PURPOSE: Following adult stroke, dysphagia, dysarthria, and aphasia are common sequelae. Little is known about these impairments in pediatric stroke. We assessed frequencies, co-occurrence and associations of dysphagia, oral motor, motor speech, language impairment, and caregiver burden in pediatric stroke. METHODS: Consecutive acute patients from term birth-18 years, hospitalized for arterial ischemic stroke (AIS), and cerebral sinovenous thrombosis, from January 2013 to November 2018 were included. Two raters reviewed patient charts to detect documentation of in-hospital dysphagia, oral motor dysfunction, motor speech and language impairment, and caregiver burden, using a priori operational definitions for notation and assessment findings. Other variables abstracted included demographics, preexisting conditions, stroke characteristics, and discharge disposition. Impairment frequencies were obtained by univariate and bivariate analysis and associations by simple logistic regression. RESULTS: A total of 173 patients were stratified into neonates (N=67, mean age 2.9 days, 54 AIS, 15 cerebral sinovenous thrombosis) and children (N=106, mean age 6.5 years, 73 AIS, 35 cerebral sinovenous thrombosis). Derived frequencies of impairments included dysphagia (39% neonates, 41% children); oral motor (6% neonates, 41% children); motor speech (37% children); and language (31% children). Common overlapping impairments included oral motor and motor speech (24%) and dysphagia and motor speech (23%) in children. Associations were found only in children between stroke type (AIS over cerebral sinovenous thrombosis) and AIS severity (more severe deficit at presentation) for all impairments except feeding impairment alone. Caregiver burden was present in 58% patients. CONCLUSIONS: For the first time, we systematically report the frequencies and associations of dysphagia, oral motor, motor speech, and language impairment during acute presentation of pediatric stroke, ranging from 30% to 40% for each impairment. Further research is needed to determine long-term effects of these impairments and to design standardized age-specific assessment protocols for early recognition following stroke.

Pediatric Hyperacute Arterial Ischemic Stroke Pathways at Canadian Tertiary Care Hospitals.

BACKGROUND: Childhood acute arterial ischemic stroke (AIS) is diagnosed at a median of 23 hours post-symptom onset, delaying treatment. Pediatric stroke pathways can expedite diagnosis. Our goal was to understand the similarities and differences between Canadian pediatric stroke protocols with the aim of optimizing AIS management. METHODS: We contacted neurologists at all 16 Canadian pediatric hospitals regarding AIS management. Established protocols were analyzed for similarities and differences in eight domains. RESULTS: Response rate was 100%. Seven (44%) centers have an established AIS protocol and two (13%) have a protocol under development. Seven centers do not have a protocol; two redirect patients to adult neurology, five rely on a case-by-case approach for management. Analysis of the seven protocols revealed differences in: 1) IV-tPA dosage: age-dependent 0.75-0.9 mg/kg (N = 1) versus age-independent 0.9 mg/kg (N = 6), with maximum doses of 75 mg (N = 1) or 90 mg (N = 6); 2) IV-tPA lower age cut-off: 2 years (N = 5) versus 3 or 10 years (each N = 1); 3) IV-tPA exclusion criteria: PedNIHSS score <4 (N = 3), <5 (N = 1), <6 (N = 3); 4) first choice of pre-treatment neuroimaging: computed tomography (CT) (N = 3), magnetic resonance imaging (MRI) (N = 2) or either (N = 2); 5) intra-arterial tPA use (N = 3) and; 6) mechanical thrombectomy timeframe: <6 hour (N = 3), <24 hour (N = 2), unspecified (N = 2). CONCLUSIONS: Although 44% of Canadian pediatric hospitals have established AIS management pathways, several differences remain among centers. Some criteria (dosage, imaging) reflect adult AIS literature. Canadian expert consensus regarding IV-tPA and endovascular treatment should be established to standardize and implement AIS protocols across Canada.

Bow hunter syndrome: A rare yet important etiology of posterior circulation stroke.

A6-year-oldgirl presented with acute-onset headache andfluctuating right-sided weakness.HerPedNIHSSwas13. Brain MRI/MRA showed acute pontine arterial ischemic stroke(AIS)and remote right cerebellar and thalamic infarcts.No antecedent trauma or other stroke risk factors were identified. Clinical suspicion of bow hunter syndromewas raised. CTshowed congenital C2-C3 fusion and dynamic angiogramconfirmed the diagnosis. The management challenges of this rare condition are discussed below.