Impact of COVID-19 pandemic in natural course of Moyamoya Angiopathy: an experience from tertiary-care-center in India

Background COVID-19 mediated immune dysregulation and cytokine storm can precipitate and aggravate Moyamoya angiopathy (MMA), influencing its disease course. This index study was undertaken to prospectively evaluate the status of neurological symptoms of MMA in relation to COVID-19 affection. Methodology and results Follow-up MMA patients of institute’s Stroke-clinic were telephonically interview from 24th March to 30th September, 2020. The first call familiarized them with COVID-19 symptoms and neurological manifestations of MMA, followed by monthly-calls with predesigned questionnaire. Patients with suggestion of COVID-19 underwent nasopharyngeal-swab-testing for COVID-19 Reverse transcription-polymerase chain reaction (RT-PCR) positive cases were subjected to antibody levels for COVID-19 Enzyme-linked immunoassay (ELISA) 8–12 weeks after recovery. During symptomatic phase till 14 days of asymptomatic, they were contacted daily/alternate day. Any new onset/worsening of neurological symptoms were noted. The baseline clinico-radiological details were obtained from stroke-clinic registery. Subsequently, all data were analyzed and compared using descriptive statistics. Seventy four of 104 MMA patients could be contacted and enrolled. The mean age, time since last follow-up and compliance to previously prescribed medication were 23.5 ± 16.1 years, 9.2 ± 1.7 months and 90.5% (n = 67), respectively. Aggravation/new onset neurological symptom were seen in 64.3% (n = 9) of COVID-19 positive MMA (n = 14), of which 8 were seen among the 11 pediatric COVID-19 positive MMA [(Transient ischemic attacks) TIA-4, TIA with headache-1, seizure-2, stroke causing mortality-1]. Conclusion COVID-19 infection can potentiate MMA causing significant morbidity and mortality, especially in children. Providing optimal care for severe diseases (such as MMA) in developing countries during pandemic remains a challenge.

Hemodynamic evaluation of patients with Moyamoya Angiopathy: comparison of resting-state fMRI to breath-hold fMRI and [15O]water PET

Purpose Patients with Moyamoya Angiopathy (MMA) require hemodynamic evaluation to assess the risk of stroke. Assessment of cerebral blood flow with [15O]water PET and acetazolamide challenge is the diagnostic standard for the evaluation of the cerebral perfusion reserve (CPR). Estimation of the cerebrovascular reactivity (CVR) by use of breath-hold-triggered fMRI (bh-fMRI) as an index of CPR has been proposed as a reliable and more readily available approach. Recent findings suggest the use of resting-state fMRI (rs-fMRI) which requires minimum patient compliance. The aim of this study was to compare rs-fMRI to bh-fMRI and [15O]water PET in patients with MMA. Methods Patients with MMA underwent rs-fMRI and bh-fMRI in the same MRI session. Maps of the CVR gained by both modalities were compared retrospectively by calculating the correlation between the mean CVR of 12 volumes of interest. Additionally, the rs-maps of a subgroup of patients were compared to CPR-maps gained by [15O]water PET. Results The comparison of the rs-maps and the bh-maps of 24 patients revealed a good correlation (Pearson’s r = 0.71 ± 0.13; preoperative patients: Pearson’s r = 0.71 ± 0.17; postoperative patients: Pearson’s r = 0.71 ± 0.11). The comparison of 7 rs-fMRI data sets to the corresponding [15O]water PET data sets also revealed a high level of agreement (Pearson’s r = 0.80 ± 0.19). Conclusion The present analysis indicates that rs-fMRI might be a promising non-invasive method with almost no patient cooperation needed to evaluate the CVR. Further prospective studies are required.

The angiographic presentation of European Moyamoya angiopathy

Background and purpose Little is known about the angiographic presentation of Moyamoya angiopathy (MMA) in non-Asian patients. Methods Conventional cerebral angiograms from 155 Caucasian patients diagnosed as MMA were analyzed with respect to extracranial champagne bottle neck sign, Suzuki stages, collateral status, as well as presence of aneurysms and posterior cerebral artery stenosis. Results In 84 of 155 angiograms, the extracranial carotid artery was visualized, in 65 of them (77.4%), a champagne bottle neck sign was noted. Of the 278 analyzable hemispheres, 13.7%,11.2%, 37.8%, 27.3%, 8.6%, and 1.4% were classified as Suzuki stage I, stage II, stage III, stage IV, stage V, and stage VI, respectively. Among 280 hemispheres, in 53 hemispheres (18.9%) isolated basal collaterals (pathway I) and in 104 hemispheres (37.1%) choroidal and pericallosal collaterals (including basal collaterals, pathway II) were found. In 74 hemispheres (26.4%) ethmoidal collaterals (pathways III), and in 17 hemispheres (6.1%) vault collaterals were visualized. Patients with higher Suzuki stages IV–VI (p = 0.008) and ethmoidal collaterals (p < 0.001) suffered more often from cerebral hemorrhage. Transient ischemic attacks occurred more frequently in patients with Suzuki stage I to III (p < 0.001). In 10 of 155 patients (6.5%), the angiogram revealed a cerebral aneurysm. In 13 patients (8.4%), a stenotic P1 segment of the posterior cerebral artery was found. Conclusions This is so far the largest observational study about angiography in Caucasian European MMA patients. A comparison with Asian data indicates similarity of disease in Caucasian and Asian patients.

Assessment of cerebrovascular insufficiency with MR-ASL perfusion in patients with moyamoya angiopathy

Purpose. To develop a methodology for assessing the degree of cerebrovascular insufficiency in patients with moyamoya angiopathy (AMM) based on measurement of cerebral blood flow (CBF) and determination the presence of arterial transit artifact (ATA) using MR method of arterial spin labeling (ASL).Materials and methods. The study included 47 patients with AMM who underwent 148 MR studies in PCASL mode (296 hemispheres), of which 47 (94 hemispheres) were done before surgical treatment. On received perfusion maps 7 areas of interest (ROI) were manually set in the gray and white matter of the brain using “Fusion” technique outside the ATA zones. The CBF values at the central point of the ATA were estimated. In the preoperative stage, 47 patients underwent direct angiography to assess the stage of the disease according to Suzuki, the presence and severity of leptomeningeal and transdural collaterals and MR angiography to assess the stage of the disease according to Houkin and the level of ICA stenosis. Statistical processing included univariate analysis of variance (ANOVA) and chi-square test (IBM SPSS Statistics 23).Results. ATA was detected in 77% of studies (69% of hemispheres). The average minimum CBF in ATA was 120.2 ± 21.1 ml/min/ 100 g at the lower bound of the confidence interval of 117.43 ml/min / 100 g. The average maximum CBF in ATA was 234.9. Depending on the CBF values in the MCA territory and the presence of ATA, 4 degrees of perfusion deficiency were identified: degree 0 (CBF = 64.5 ± 16.2 ml/min / 100 g, without ATA) corresponded to the stage of “compensation” of cerebral blood flow, degree 1 (CBF = 61.5 ± 16.6 ml/min/ 100 g, with ATA) – “subcompensation”, degree 2 (CBF = 26.5 ± 7.2 ml/min/100 g, with ATA) – “initial decompensation”, degree 3 (CBF = 16.0 ± 4.7 ml/min / 100 g, without ATA) – “decompensation”. The highlighted degrees statistically significantly differed among themselves in all ROIs (p < 0.0001). More severe perfusion deficiency corresponded to the more developed stages of AMM according to Suzuki and Houkin, proximal stenosis of the ICA (p < 0.0001), and more severe neurological deficit (p < 0.02). The occurrence of ATA reliably reflected the presence of leptomeningeal collaterals (p < 0.001).Conclusions. The proposed method for assessing patterns of ASL perfusion has a good agreement with the stage of the disease, the presence of sources of collateral circulation, the severity of neurological deficit and can be used to assess cerebrovascular insufficiency in patients with AMM.