Research Progress of Moyamoya Disease in Children

The usefulness of super-selective arterial spin labeling for postoperative evaluation of pediatric moyamoya disease: technical note

Moyamoya disease is characterized by progressive internal carotid artery (ICA) occlusion. Extracranial-intracranial bypass surgery is effective, particularly in pediatric patients; imaging plays a crucial role in evaluating intracranial perfusion pre- and post-surgery. Arterial spin labeling (ASL) is a magnetic resonance technique employed for noninvasive, whole-brain perfusion assessment by magnetically labeling inflowing blood. However, ASL cannot evaluate the territories and development of each vessel perfusion compared with digital subtraction angiography (DSA). Recently, super-selective ASL (SS-ASL) has been developed, performing pinpoint labeling on a specific artery at a time, and offering a tomographic view that distinctly displays blood supply areas for each vessel. Unlike DSA, SS-ASL is noninvasive and can be repeatedly performed in pediatric patients. In conclusion, SS-ASL is useful for evaluating bypass development over time and understanding the pathophysiology of pediatric moyamoya disease.

Isolated anterior cerebral artery occlusion: an atypical form of moyamoya disease

BACKGROUND

The relationship between anterior cerebral artery (ACA) occlusion and moyamoya disease (MMD) has rarely been studied. In this study, we focused on a special type of MMD: isolated ACA-occlusive MMD. We investigated clinical attributes, genotypes and progression risk factors in patients with ACA-occlusive MMD, providing initial insights into the relationship between ACA occlusion and MMD.

METHODS

We retrospectively analysed digital subtraction angiography (DSA) from 2486 patients and diagnosed 139 patients with ACA-occlusive MMD. RNF213 p.R4810K (rs112735431) mutation analysis was performed. Patients were categorised into progression and non-progression groups based on whether they progressed to typical MMD. Differences in clinical characteristics, neuropsychological assessment, radiological findings and genotypes were evaluated. Logistic regression analyses identified risk factors for ACA-occlusive MMD progression.

RESULTS

The median age of patients with ACA-occlusive MMD was 36 years, and the primary symptom was transient ischaemic attack (TIA). 72.3% of ACA-occlusive MMD patients had cognitive decline. Of 116 patients who underwent RNF213 gene mutation analysis, 90 patients (77.6%) carried the RNF213 p.R4810K GG allele and 26 (22.4%) carried the GA allele. Of 102 patients with follow-up DSA data, 40 patients (39.2%) progressed. Kaplan-Meier curve estimates indicated a higher incidence of ischaemic stroke in the progression group during follow-up (p=0.035). Younger age (p=0.041), RNF213 p.R4810K GA genotype (p=0.037) and poor collateral compensation from the middle cerebral artery (MCA) to ACA (p<0.001) were risk factors of ACA-occlusive MMD progression to typical MMD.

CONCLUSIONS

Cognitive decline and TIA might be the main manifestations of ACA-occlusive MMD. Isolated ACA occlusion may be an early signal of MMD. The initial lesion site of MMD is not strictly confined to the terminal portion of the internal carotid artery. Younger patients, patients with RNF213 p.R4810K GA genotype or those with inadequate MCA-to-ACA compensation are more likely to develop typical MMD.

How to reduce the complication rate of multiple burr holes surgery in moyamoya angiopathy

PURPOSE

This study is aimed at analyzing clinical outcome, absence of stroke recurrence, revascularization, and complications and long-term follow-up in the surgical treatment of moyamoya angiopathy (MMA) using the multiple burr holes (MBH) technique with dura opening and arachnoid preservation as a single procedure. To the best of our knowledge, this is the first to describe an MBH technique with arachnoid preservation.

METHOD

We retrospectively reviewed all patients operated from June 2001 to March 2021, for a symptomatic and progressive MMA operated with opening of the dura but arachnoid preservation. Clinical examinations were obtained in all patients, and radiological monitoring was performed by cerebral 3D-magnetic resonance angiography (MRA) with perfusion or single-photon emission computed tomography (SPECT) with acetazolamide.

RESULTS

In total, 21 consecutive patients (6 children and 15 adults) were included with a mean age of 7.4 years in the pediatric group and 36.9 years in the adult group. Initial presentation was permanent ischemic stroke in 15 cases, transient ischemic attack (TIA) in 5 cases, and cerebral hemorrhage in one case. The MBH with dura opening and arachnoid preservation was performed bilaterally in 9 cases (43%) and unilaterally in 12 cases (57%). One patient died due to intraoperative bilateral ischemic stroke. Of the 20 other patients, 30% demonstrated clinical stability and 70% showed partial or complete recovery. Although one patient experienced a perioperative stroke, we did not observe any pseudomeningocele or postoperative ischemic stroke (IS) recurrence in all surviving cases during the average follow-up period of 55.5 months (range: 1-195). These outcomes emphasize the importance of preoperative monitoring to ensure the effectiveness and safety of the intervention. Postoperative angiography studies showed revascularization in 96.3% of treated hemispheres (100% in the adult group vs 80% in the pediatric group).

CONCLUSIONS

Our results on this small cohort suggest that the MBH technique with opening of the dura and arachnoids preservation can prevent recurrent strokes and reduce the risk of pseudomeningocele.

Potential of unilateral combined bypass surgery to accelerate contralateral radiological progression in pediatric moyamoya disease

Background

Surgical cerebral revascularization is recommended for treating pediatric moyamoya disease (MMD). However, whether unilateral combined bypass surgery can cause disease progression on the contralateral side is uncertain. The study aimed to investigate the vascular architecture and regional cerebral blood flow (rCBF) status of patients with pediatric MMD after successful unilateral combined bypass surgery and to identify the possible risk factors.

Methods

Pediatric patients diagnosed with MMD and admitted to Xuanwu Hospital who underwent combined bypass surgery between 2019 and 2021 were enrolled. Digital subtraction angiography (DSA) and magnetic resonance imaging (MRI) with arterial spin labeling (ASL) were performed to investigate the vascular architecture and rCBF during surgery and at short-term follow-up. Suzuki's angiographic staging and moyamoya vessel grading system were both used. Progression was defined as an increase in either Suzuki stage or moyamoya vessel grade detected after unilateral surgery. All analyses were performed with conventional statistic methods.

Results

A total of 27 successive patients with a median age of 8 [interquartile range (IQR), 5-14] years old were identified. On the non-operated (non-OP) side, 11 (40.7%) patients demonstrated progression, all of whom showed an increase in the moyamoya vessel grade, and 5 also displayed Suzuki stage progression during the median 4.7 (IQR, 3.7-5.7) months follow-up. However, rCBF barely changed on the non-OP side compared to preoperation [preoperation: median, 49.6, (IQR, 42.9-61.1) mL/100 g/min; postoperation: median, 50.2, (IQR, 43.5-59.3) mL/100 g/min; P=0.445].

Conclusions

Combined bypass surgery might accelerate the radiological progression on the contralateral side, which occurs before the decline of rCBF. Those with earlier Suzuki stage MMD of the non-OP side are prone to rapid progression after unilateral combined revascularization.

Physiological and pathophysiological mechanisms of the molecular and cellular biology of angiogenesis and inflammation in moyamoya angiopathy and related vascular diseases

Rationale

The etiology and pathophysiological mechanisms of moyamoya angiopathy (MMA) remain largely unknown. MMA is a progressive, occlusive cerebrovascular disorder characterized by recurrent ischemic and hemorrhagic strokes; with compensatory formation of an abnormal network of perforating blood vessels that creates a collateral circulation; and by aberrant angiogenesis at the base of the brain. Imbalance of angiogenic and vasculogenic mechanisms has been proposed as a potential cause of MMA. Moyamoya vessels suggest that aberrant angiogenic, arteriogenic, and vasculogenic processes may be involved in the pathophysiology of MMA. Circulating endothelial progenitor cells have been hypothesized to contribute to vascular remodeling in MMA. MMA is associated with increased expression of angiogenic factors and proinflammatory molecules. Systemic inflammation may be related to MMA pathogenesis.

Objective

This literature review describes the molecular mechanisms associated with cerebrovascular dysfunction, aberrant angiogenesis, and inflammation in MMA and related cerebrovascular diseases along with treatment strategies and future research perspectives.

Methods and results

References were identified through a systematic computerized search of the medical literature from January 1, 1983, through July 29, 2022, using the PubMed, EMBASE, BIOSIS Previews, CNKI, ISI web of science, and Medline databases and various combinations of the keywords "moyamoya," "angiogenesis," "anastomotic network," "molecular mechanism," "physiology," "pathophysiology," "pathogenesis," "biomarker," "genetics," "signaling pathway," "blood-brain barrier," "endothelial progenitor cells," "endothelial function," "inflammation," "intracranial hemorrhage," and "stroke." Relevant articles and supplemental basic science articles almost exclusively published in English were included. Review of the reference lists of relevant publications for additional sources resulted in 350 publications which met the study inclusion criteria. Detection of growth factors, chemokines, and cytokines in MMA patients suggests the hypothesis of aberrant angiogenesis being involved in MMA pathogenesis. It remains to be ascertained whether these findings are consequences of MMA or are etiological factors of MMA.

Conclusions

MMA is a heterogeneous disorder, comprising various genotypes and phenotypes, with a complex pathophysiology. Additional research may advance our understanding of the pathophysiology involved in aberrant angiogenesis, arterial stenosis, and the formation of moyamoya collaterals and anastomotic networks. Future research will benefit from researching molecular pathophysiologic mechanisms and the correlation of clinical and basic research results.

Same-day versus staged revascularization of bilateral moyamoya arteriopathy in pediatric patients

PURPOSE

To compare the outcomes of conducting left and right hemisphere surgical revascularization on the same day versus different days for bilateral pediatric moyamoya arteriopathy patients.

METHODS

We retrospectively analyzed mortality, stroke, and transient neurologic event (TNE) rates in North American bilateral pediatric moyamoya arteriopathy patients who underwent bilateral cerebral revascularization.

RESULTS

A total of 38 pediatric (≤ 18 years old) patients at our institution underwent bilateral cerebral revascularization for moyamoya arteriopathy. Of these patients, 24 (63.2%) had both operations on the same day and 14 (36.8%) had the two operations on different days. The average length of stay for patients who underwent same-day bilateral revascularization was 6.9 ± 2.0 days and the average length of stay for each operation for patients who underwent staged bilateral revascularization was 4.5 ± 1.4 days, p = 0.001. While there were 7 (14.6%) postoperative strokes in patients who had both hemispheres revascularized on the same day, 0 (0%) strokes occurred in hemispheres after they had been operated on in the staged cohort, p = 0.042. Additionally, the postoperative stroke-free survival time in the ipsilateral hemisphere and TNE-free survival time were significantly longer in patients in the staged revascularization cohort.

CONCLUSION

Same-day bilateral revascularization was associated with longer length of stay per operation, higher rate of ipsilateral stroke, and shorter postoperative TNE-free and stroke-free survival time in the revascularized hemisphere.

Computational Modelling of Cerebral Blood Flow Rate at Different Stages of Moyamoya Disease in Adults and Children

Moyamoya disease is a cerebrovascular disorder which causes a decrease in the cerebral blood flow rate. In this study, a lumped parameter model describing the pressures and flow rates in the heart chambers, circulatory system, and cerebral circulation with the main arteries in the circle of Willis, pial circulation, cerebral capillaries, and veins was used to simulate Moyamoya disease with and without coarctation of the aorta in adults and children. Cerebral blood flow rates were 724 mL/min and 1072 mL/min in the healthy adult and child cardiovascular system models. The cerebral blood flow rates in the adult and child cardiovascular system models simulating Moyamoya disease were 676 mL/min and 1007 mL/min in stage 1, 627 mL/min and 892 mL/min in stage 2, 571 mL/min and 831 in stage 3, and 444 and 537 mL/min in stage 4. The cerebral blood flow rates were 926 mL/min and 1421 mL/min in the adult and child cardiovascular system models simulating coarctation of the aorta. Furthermore, the cerebral blood flow rates in the adult and child cardiovascular system model simulating Moyamoya disease with coarctation of the aorta were 867 mL/min and 1341 mL/min in stage 1, 806 mL/min and 1197 mL/min in stage 2, 735 mL/min and 1121 in stage 3, and 576 and 741 mL/min in stage 4. The numerical model utilised in this study can simulate the advancing stages of Moyamoya disease and evaluate the associated risks with Moyamoya disease.

Salvage multiple burr hole surgery in patients with Moyamoya disease: efficacy evaluation using probabilistic independent component analysis of dynamic susceptibility contrast perfusion MRI

PURPOSE

Multiple burr hole surgery is considered to be an option for achieving indirect revascularization in patients with ischemic Moyamoya disease (MMD). We aimed to investigate the efficacy of stand-alone multiple burr hole surgery for salvage revascularization in patients with MMD by assessing the hemodynamic changes via normalized time-to-peak (nTTP) analysis and independent component analysis (ICA) of preoperative and postoperative dynamic susceptibility contrast (DSC) perfusion MRI data.

METHODS

The DSC perfusion MRI data of 25 hemispheres from 21 patients with MMD, who underwent multiple burr hole surgery for salvage revascularization due to persistent or recurrent symptoms after primary revascularization with modified encephaloduroarteriosynangiosis (mEDAS), were analyzed. The nTTP, which was measured using the region of interests covering the entire surgical hemisphere, was compared between the preoperative and postoperative images. ICA was used to compare the relative arterial and venous components of the surgical hemispheres between the respective preoperative and postoperative images.

RESULTS

The median postoperative nTTP (1.80 s) was significantly shorter than the median preoperative nTTP (4.10 s) (P < 0.001). The postoperative relative arterial component of the surgical hemisphere (median: 0.04) was significantly higher than the preoperative relative arterial component (median: - 0.02, P < 0.001). In contrast, the postoperative relative venous component of the surgical hemisphere (median: - 0.05) was significantly lower than the preoperative value (median: 0.05, P < 0.001).

CONCLUSION

The improvement in cerebral perfusion parameters observed on postoperative DSC perfusion MRI demonstrated that stand-alone multiple burr hole surgery could be a favorable salvage revascularization technique after mEDAS failure in patients with ischemic MMD.

Cerebral Perfusion in Pediatric Stroke: Children Are Not Little Adults

ABSTRACT

Cerebral perfusion imaging provides useful information about the hemodynamic state of the brain that is relevant to a number of neurologic conditions, including stroke, epilepsy, and brain tumors. Multiple imaging modalities have been developed to evaluate brain perfusion, primarily by the use of different tracers to measure cerebral blood volume and cerebral blood flow. Here, we provide an overview of magnetic resonance imaging perfusion techniques; summarize the role of perfusion imaging in adult stroke; describe changes in cerebral blood flow over childhood; and discuss the relevance and future directions of perfusion imaging in pediatric cerebrovascular disorders and stroke.

Validation and Extension Study Exploring the Role of RNF213 p.R4810K in 2,877 Chinese Moyamoya Disease Patients

OBJECTIVE

To validate, update, and extend the role of RNF213 p.R4810K (G>A) for predicting the phenotype of moyamoya disease (MMD) patients and explore the different effects on pediatric and adult groups.

METHODS

A total of 2,877 patients conducted from 2004 to 2018 were included. Review Manage 5.3 and SPSS 20.0 were applied to complete all statistical analyses. Information on age at onset, sex, initial symptom, family history and complications were obtained via retrospective chart review. Angiographic records were evaluated.

RESULTS

In China, geographic proximity to Korea or Japan may affect the carrying rate of RNF213 p.R4810K. The proportion of patients with the following characteristics was significantly higher (P <0.017) in the GA than in the GG group: female, age at onset < 18 years, infarct after transient ischemic attack, family history of MMD, and posterior cerebral artery involvement. For pediatric patients, GA showed more cerebral hemorrhage (CH) (odds ratios (ORs) [95% confidence intervals (CIs)] = 3.99 (1.61-9.88), P = 0.003), more patients were in the Suzuki early and intermediate stage (P = 0.001; P = 0.001, respectively), while for the adult group, GA indicated more female (OR [95% CIs] = 1.43 [1.15-1.79], P = 0.001), fewer patients with diabetes (0.58 [0.38-0.86], P = 0.007) and intermediate Suzuki stage (P = 3.70 × 10^-4).

CONCLUSIONS

The incidence and carrying rates of RNF213 p.R4810K in various regions for Chinese MMD patients were obviously different. RNF213 p.R4810K has different predictive effects on phenotypes of pediatric and adult patients.

Clinical Presentation and Stroke Incidence Differ by Moyamoya Etiology

INTRODUCTION

Moyamoya arteriopathy, which can be idiopathic or associated with sickle cell disease, neurofibromatosis, Down syndrome, or cranial radiation therapy, is a progressive cerebral arteriopathy associated with high rates of incident and recurrent stroke. Little is known about how these subgroups differ with respect to clinical presentation, radiographic findings, stroke risk, and functional outcomes.

METHODS

Using ICD codes, we identified children ages 28 days to 18 years treated for moyamoya arteriopathy at our tertiary care center between 2003 and 2019. Demographic, clinical, and radiographic data were extracted from the medical record. The Pediatric Stroke Recurrence and Recovery Questionnaire was administered to consenting participants.

RESULTS

Sixty-nine patients met inclusion criteria (33 idiopathic, 18 sickle cell disease, 11 neurofibromatosis, 6 Down syndrome, 1 cranial radiation therapy). Median follow-up time was 7.7 years; 24 patients had at least 5 years of follow-up data. Frequency of stroke at presentation differed by subgroup (P < .001). Of patients with at least 2 years of follow-up, 33 (55%) experienced stroke. The proportion of patients experiencing stroke differed by subgroup (50% of idiopathic cases, 72% of sickle cell disease, 11% of neurofibromatosis, and 100% of Down syndrome, P = .003). The frequency of bilateral versus unilateral disease (P = .001) and stroke-free survival following presentation (P = .01) also differed by subgroup.

CONCLUSIONS

In this single-center cohort, moyamoya subgroups differed with respect to clinical and radiographic characteristics, with neurofibromatosis-associated moyamoya syndrome having a milder phenotype and Down syndrome-associated moyamoya portending a more aggressive course. These findings need confirmation in a larger, multi-center cohort with longer duration of follow-up.

The trend of indirect anastomosis formation in a 2-vessel occlusion plus encephalo-myo-synangiosis rat model

Background

Basic research on the factors influencing indirect anastomosis formation in a 2-vessel occlusion plus encephalo-myo-synangiosis (2VO + EMS) rat model is conducive to improving the efficacy of indirect revascularization surgery in the clinic. However, the time point at which anastomosis between the rat temporal muscle (TM) and brain naturally has the greatest effect after encephalo-myo-synangiosis (EMS) remains unknown. Therefore, we conducted this study to explore the peak time of indirect anastomosis formation in the 2VO + EMS rat model.

Methods

Forty 2VO + EMS rats were randomly divided into five groups (n=8) according to the length of time (by week) after EMS, and 2VO rats were used as the control group (n=8). The expression of vascular endothelial growth factor (VEGF) and CD31 on the EMS side of the brain, perfusion ratio [improvement of cerebral blood perfusion (CBP) on the EMS side] and Morris water maze (MWM) results were compared between groups. Furthermore, the trends of the above variables were explored over weeks.

Results

Overall, the expression of VEGF and CD31, the perfusion ratio and the cognitive improvement in the 2VO + EMS rat model gradually increased over weeks after EMS. The VEGF and CD31 expression (as detected by immunofluorescence), perfusion ratio and number of times crossing the platform area peaked at 4 weeks after EMS. In addition, both the escape latency and the time spent in the target quadrant peaked in the fifth week after EMS.

Conclusions

After establishing the 2VO + EMS rat model, the degree of endothelial cell (EC) proliferation and CBP improvement on the EMS side of the brain peaked at 4 weeks after EMS, whereas the cognitive improvement peaked in the fifth week.

PedsQL Score Post Encephalo-duro-arterio-myo-synangiosis Procedure for Moyamoya Disease: A Single Center Experience

BACKGROUND

Moyamoya disease is a progressive, occlusive arteriopathy of the intracranial vessels causing an increased risk of stroke. It often results in functional impairment and decrease in quality of life, both in the presence and absence of stroke. Revascularization is the accepted treatment for patients with symptomatic moyamoya disease, preventing further stroke. At Leeds Children's Hospital we use the encephalo-duro-arterio-myo-synangiosis (EDAMS) technique to facilitate revascularization. We aim to assess the quality of life outcomes of patients who have undergone operative intervention at our unit for moyamoya disease.

METHODS

Pediatric patients with operated moyamoya disease from Leeds Children Hospital between February 2009 and January 2019 were included. Patients awaiting primary surgery were excluded. Patients were contacted via telephone and the Pediatric Quality of Life Inventory 4.0 (PedsQL) questionnaire administered via parent proxy. Quality of life outcomes were assessed using the PedsQL questionnaire score, which measures physical, emotional social and school functioning domains. This score was then converted to a health-related quality of life score. Scores in each domain and mean scores were compared with normative data.

RESULTS

This study included 11 children (5 boys), median age 6.8 years (range: 22 months to 15.5 years), and 9 children underwent bilateral operations. Mean parent proxy PedsQL score was 66 (range: 12.5-98.4), with a mean score of 61.9 in physical function, 88.9 in emotional function, 70.9 in social function, and 58.7 in school function. This was lower than healthy controls overall and in each individual domain except emotional function, which was similar to normative data.

CONCLUSIONS

Children with moyamoya disease have a lower quality of life than healthy controls within this series. This suggests that children with moyamoya should be offered additional psychosocial support within the community.

Postoperative change of neuropsychological function after indirect revascularization in childhood moyamoya disease: a correlation with cerebral perfusion study

PURPOSE

The relationships between postoperative functional improvement in various cognitive domains and regional hemodynamic change have not been sufficiently studied in childhood moyamoya disease (MMD). The present study aimed to examine the cognitive benefit of indirect revascularization, the underlying biological mechanism, and factors affecting surgical outcome in childhood MMD.

METHODS

Twenty-three patients with MMD aged under 20 years received neuropsychological examinations before and after indirect revascularization surgery, evaluating intellectual function, verbal and visual memory, and executive function. Among them, 13 patients had magnetic resonance perfusion (MRP) studies, in which regional cerebral perfusion was rated.

RESULTS

Postoperative improvement was observed in verbal memory performances (p = 0.02-0.03) and in cerebral perfusion at all 26 cerebral hemispheres (p = 0.003-0.005), especially in the middle cerebral artery (MCA) territories (p = 0.001-0.003). Hemodynamic improvement in the left MCA territories was significantly correlated with improvement of both verbal new learning (p = 0.01) and intellectual function (p = 0.004). Postoperative cognitive improvement of immediate recall and verbal intellectual function was associated with female sex (r = - 0.42) and symptom duration (p = - 0.03), respectively. Hemodynamic improvement in the MCA territories was related to longer follow-up intervals (p = 0.02).

CONCLUSION

The findings revealed that the selective postoperative cognitive improvement was associated with increased regional perfusion in the MCA territories, and indicate the importance of early intervention and the potential of indirect revascularization regarding long-term outcome.

Early Diffusion Magnetic Resonance Imaging Changes in Normal-Appearing Brain in Pediatric Moyamoya Disease

BACKGROUND

Moyamoya disease often leads to ischemic strokes visible on diffusion-weighted imaging (DWI) and T2-weighted magnetic resonance imaging (MRI) with subsequent cognitive impairment. In adults with moyamoya, apparent diffusion coefficient (ADC) is correlated with regions of steal phenomenon and executive dysfunction prior to white matter changes.

OBJECTIVE

To investigate quantitative global diffusion changes in pediatric moyamoya patients prior to explicit structural ischemic damage.

METHODS

We retrospectively reviewed children (<20 yr old) with moyamoya disease and syndrome who underwent bypass surgery at our institution. We identified 29 children with normal structural preoperative MRI and without findings of cortical infarction or chronic white matter ischemic changes. DWI datasets were used to calculate ADC maps for each subject as well as for 60 age-matched healthy controls. Using an atlas-based approach, the cerebral white matter, cerebral cortex, thalamus, caudate, putamen, pallidum, hippocampus, amygdala, nucleus accumbens, and brainstem were segmented in each DWI dataset and used to calculate regional volumes and ADC values.

RESULTS

Multivariate analysis of covariance using the regional ADC and volume values as dependent variables and age and gender as covariates revealed a significant difference between the groups (P < .001). Post hoc analysis demonstrated significantly elevated ADC values for children with moyamoya in the cerebral cortex, white matter, caudate, putamen, and nucleus accumbens. No significant volume differences were found.

CONCLUSION

Prior to having bypass surgery, and in the absence of imaging evidence of ischemic stroke, children with moyamoya exhibit cerebral diffusion changes. These findings could reflect microstructural changes stemming from exhaustion of cerebrovascular reserve.

A rare case of pediatric moyamoya disease with reversible white matter lesions in a 3-year-old Chinese girl

Moyamoya disease is a chronic cerebral vascular disease characterized by progressive occlusion of the cerebral arteries and resulting in the development of abnormal collateral circulation. We report a case of moyamoya disease in a 3-year-old Chinese girl with partly reversible white matter lesions. This case indicates that, in pediatric moyamoya disease, white matter lesions may be associated with cerebral ischemia, and they may be reversible after treatment.

Angiographic study of the transdural collaterals at the anterior cranial fossa in patients with Moyamoya disease

Unlike its parietal, temporal, and occipital counterparts, the frontal lobe has a broad basal surface directly facing the anterior cranial fossa dura mater which could permit establishment of transdural collaterals (TDCs) with the frontal lobe. Studies on the TDCs from the anterior cranial fossa in moyamoya disease (MMD) are scarce and inadequately investigated. A retrospective study of 100 hemispheres in 50 patients who were diagnosed with MMD by catheter angiography between January 2015 and June 2019 was performed in our institution. TDCs through the anterior ethmoid artery (AEA) or posterior ethmoid artery (PEA) were divided into 3 types respectively based on their respective angioarchitecture. Furthermore, we also studied TDCs to the temporal, parietal, and occipital lobes and collaterals from the posterior circulation to the territory of the anterior cerebral artery. TDCs through the AEA and PEA were identified in 89 (89/100, 89%) and 73 (73/100, 73%) of the hemispheres. The vascularization state of the frontal lobe was good in 89 (89/100, 89%) hemispheres. Rete mirabile and TDCs through the PEA were statistically different among patients with different Suzuki stages. No statistical difference was noted in TDCs through the AEA, frontal TDCs from other sources, and the vascularization state of the frontal lobe with regard to different Suzuki stages. TDCs through the AEA and PEA at the anterior cranial fossa play a very important role in compensating the ischemic frontal lobe. The frontal lobe could be well compensated in most of the patients with TDCs at the anterior cranial fossa.

Comparison of Long-Term Effect Between Direct and Indirect Bypass for Pediatric Ischemic-Type Moyamoya Disease: A Propensity Score-Matched Study

Objectives: This study aimed to compare the postoperative risks and long-term effects between direct bypass surgery (DB) and indirect bypass (IB) surgery for pediatric patients with ischemic-type moyamoya disease (MMD). Method: Pediatric patients (under or equal to 18 years old) who were diagnosed as MMD and given surgical treatments at our center between 2009 and 2015 were retrospectively reviewed from a prospective database. Pediatric hemorrhagic-type MMD patients and those who did not undergo digital subtraction angiography (DSA) were excluded. Patients who underwent DB were matched with patients who underwent IB using 1:1 propensity score matching. Postoperative complications, recurrent ischemic stroke events and modified Rankin Scale (mRS) scores at the last follow-up were compared between the matched pairs. Results: A total of 223 pediatric patients were screened, and 138 patients (DB:34, IB:104) were considered for the propensity score match. Thirty four pairs were obtained. Nine patients had postoperative complications, including 6 (17.6%) in the DB group and 3 (8.8%) in the IB group (P = 0.476). The mean follow-up period was 71.9 ± 22.2 months for the DB group and 60.2 ± 24.3 months for the IB group (P = 0.041). Kaplan-Meier analysis showed a longer stroke-free time in the DB group than in the IB group (P = 0.025). At last follow-up, good neurological status (mRS ≤ 1) was achieved in 32 (94.1%) of the DB group and 34 (100.0%) of the IB group. MRS score at last follow-up were significantly lower than at time of admission (all pts: 1.09 ± 0.45 vs. 0.28 ± 0.51, P < 0.001; DB group: 1.12 ± 0.48 vs. 0.32 ± 0.59, P < 0.001; IB group: 1.06 ± 0.42 vs. 0.24 ± 0.43, P < 0.001). Conclusion: Both techniques were effective in improving the neurological status of pediatric ischemic-type MMD patients, and direct bypass surgery might be more superior in preventing recurrent ischemic strokes in the short-term.

Epidemiology, diagnosis and treatment of moyamoya disease

Moyamoya disease (MMD) is a type of chronic cerebrovascular occlusion disease, which frequently occurs in East Asian populations, including pediatric and adult patients, and may lead to ischemic or hemorrhagic stroke, headache, epilepsy or transient ischemic attack. To date, the underlying mechanisms of MMD have remained to be fully elucidated, but certain studies have indicated that genetic factors may be an important component of its development. Cerebral angiography is the best approach for diagnosing MMD. However, with technological advances, non-invasive techniques are increasingly used to accurately evaluate MMD. MMD is commonly treated via surgery, and an increasing number of patients are benefitting from the intra- and extra-cranial revascularization. The present article provides a comprehensive review of MMD on the basis of previous research.

Clinical importance of the superficial temporal artery in neurovascular diseases: A PRISMA-compliant systematic review

The superficial temporal artery (STA) plays a very important role in neurovascular diseases and procedures. However, until now, no comprehensive review of the role of STA in neurovascular diseases from a neurosurgical perspective has ever been published. To review research on the clinical importance of STA in neurovascular diseases, a literature search was performed using the PubMed database. Articles were screened for suitability and data relevance. This paper was organized following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. According to the literature, STA is one of the terminal branches of the external carotid artery and can give off scalp, muscle, and transosseous branches. STA-middle cerebral artery (MCA) bypass is very useful for intracranial ischemic diseases, including moyamoya disease, chronic ICA and MCA insufficiency, and even acute ischemic stroke. For intracranial complex aneurysms, STA bypass remains a major option that can serve as flow replacement bypass during aneurysmal trapping or insurance bypass during temporary parent artery occlusion. Occasionally, the STA can also be involved in dural AVFs (DAVFs) via to its transosseous branches. In addition, the STA can be used as an intraoperative angiography path and the path to provide endovascular treatments. Therefore, STA is a very important artery in neurovascular diseases.

Greater ultrasonographic changes in pediatric moyamoya patients compared with adults after indirect revascularization surgeries

OBJECTIVEPediatric and adult patients with moyamoya disease experience similar clinical benefits from indirect revascularization surgeries, but there are still debates about age-related angiographic differences of the collaterals established after surgery. The goal of this study was to assess age-related differences on ultrasonography before and after indirect revascularization surgeries in moyamoya patients, focusing on some ultrasonographic parameters known to be correlated with the collaterals supplied by the external carotid artery (ECA).METHODSThe authors prospectively included moyamoya patients (50 and 26 hemispheres in pediatric and adult patients, respectively) who would undergo indirect revascularization surgery. Before surgery and at 1, 3, and 6 months after surgery, the patients underwent ultrasonographic examinations. The ultrasonographic parameters included peak-systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (RI), and flow volume (FV) measured in the ECA, superficial temporal artery (STA), and internal carotid artery on the operated side. The mean values, absolute changes, and percentage changes of these parameters were compared between the pediatric and adult patients. Logistic regression analysis was used to clarify the determinants affecting postoperative EDV changes in the STA.RESULTSBefore surgery, the adult patients had mean higher EDV and lower RI in the STA and ECA than the pediatric group (all p < 0.05). After surgery, the pediatric patients had greater changes (absolute and percentage changes) in the PSV, EDV, RI, and FV in the STA and ECA (all p < 0.05). The factors affecting postoperative EDV changes in the STA at 6 months were age (p = 0.006) and size of the revascularization area (i.e., revascularization in more than the temporal region vs within the temporal region; p = 0.009). Pediatric patients who received revascularization procedures in more than the temporal region had higher velocities (PSV and EDV) in the STA than those who received revascularization within the temporal region (p < 0.05 at 1-6 months), but such differences were not observed in the adult group.CONCLUSIONSThe greater changes of these parameters in the STA and ECA in pediatric patients than in adults after indirect revascularization surgeries indicated that pediatric patients might have a greater increase of collaterals postoperatively than adults. Pediatric patients who undergo revascularization in more than the temporal region might have more collaterals than those who undergo revascularization within the temporal region.

Moyamoya Vasculopathy in Indian Children: Our Experience

Background:

Moyamoya vasculopathy is a chronic progressive vaso-occlusive disease affecting the distal intracranial carotid arteries and their proximal branches. It is an important cause of recurrent strokes in children. Surgical revascularization procedures are now considered as the treatment option for moyamoya vasculopathy. The data from Indian children with moyamoya vasculopathy are limited to a very few studies.

Study Design:

We analyzed the records of children with moyamoya vasculopathy treated at our tertiary care center from 2000 to 2014. Our study population included all patients (aged 0–18 years) with moyamoya disease/syndrome (MMD/MMS). The demographic data, clinical characteristics, imaging, treatment details, and surgical procedures performed were reviewed.

Results:

A total of 41 patients (females-19, males-22) were identified. Thirty-three (80.48%) had MMD and eight (19.5%) had MMS. The mean age (±standard deviation) at presentation was 6.26 ± 3.79 years (range: 6 months–14 years). Majority had ischemic events at onset; none had hemorrhagic manifestations. Twenty-eight (68.29%) patients underwent surgery (a total of 33 surgical procedures, bilateral in five and unilateral in 23) and 13 (31.7%) were managed conservatively. The median duration of follow-up was 2.2 ± 1.85 years (range: 4 months–7 years). Two/thirteen patients (15%), who were managed conservatively, had recurrent strokes as against none (0/28) in the operated patients. No mortality was observed in our cohort.

Conclusion:

We agree with previous studies that Indian patients with moyamoya vasculopathy differ from their Asian and European counterparts. The availability of expertise in revascularization surgeries in various centers should prompt surgery as an efficient and safe treatment option.

Endovascular Treatment of a Patient with Moyamoya Disease and Seckel Syndrome: A Case Report

Seckel syndrome and Moyamoya diseases are different entities that rarely associated with each other. Several cases presenting with both these diseases were reported. Intracerebral artery aneurysms and collateral vessels can be seen with Moyamoya. They are commonly treated with medical treatment. We present a 12-years old patient with both Seckel syndrome and Moyamoya disease presented with middle cerebral artery aneurysm which was treated with endovascular modalities.

Analysis of the clinical characteristics of hemorrhagic moyamoya disease in the Jilin province of northeastern China: A single-center study of 212 cases

The present study aimed to investigate the clinical characteristics of hemorrhagic moyamoya disease (MMD) in Jilin province in northeast China. A total of 212 cases of hemorrhagic MMD were consecutively enrolled from the First Hospital of Jilin University in Changchun, China between January 2011 and January 2015. The patients' general clinical data, including age and gender characteristics, history of previous illnesses, hemorrhage type and onset symptoms, Hunt-Hess classification at admission, imaging characteristics, association with aneurysms, treatments and prognosis, were recorded and analyzed using SPSS 19.0. The results demonstrated that i) patients with hemorrhagic MMD in Jilin province were 47.7±11.5 years of age; ii) hemorrhagic MMD was primarily characterized by subarachnoid hemorrhage; iii) a total of 51.9% of the hemorrhagic MMD cases involved a unilateral artery; iv) a total of 24.1% of the hemorrhagic MMD cases were accompanied by anterior choroid artery and/or posterior communicating artery expansion; and v) following conservative or surgical treatment, patients with a prognostic Glasgow Outcome Scale score of 5 accounted for 65.6% of the study population. Therefore, the present study identified characteristics of MMD in Jilin province in northeast China. These results may improve understanding of the epidemiology of MMD in China, which at present remains not well established. Although the results are representative only of Jilin province in China, the study demonstrated high consistency with other studies, and thus may indirectly contribute to general understanding of hemorrhagic MMD etiology.

Moyamoya disease manifested as multiple simultaneous intracerebral hemorrhages: A case report and literature review

Multiple simultaneous intracerebral hemorrhages (MSIH) caused by Moyamoya disease (MMD) is extremely rare. To date, the clinical manifestations, imaging characteristics and mechanism of MMD-induced MSIH have not yet been elucidated. In order to improve the understanding on such cases, the present study described a rare case of MSIH caused by MMD. A 40-year-old female patient with no history of hypertension or diabetes mellitus experienced a sudden headache followed by coma. Cranial computed tomography (CT) examination revealed MSIH in the left frontal area, temporal lobe and basal ganglia. CT angiography and digital subtraction angiography examinations revealed typical characteristics of MMD. Subsequent to excluding disorders of the blood system and blood coagulation, we concluded that the present case of MSIH was caused by MMD. Hematoma evacuation and decompressive craniectomy were performed with satisfactory results. In addition, after reviewing previous MSIH cases in the literature, potential mechanisms of MMD-mediated MSIH were considered. In conclusion, MMD should be considered as a possible cause of MSIH during diagnosis and treatment. MMD can lead to pathological changes in the fragility of small arteries; therefore, rupture and hemorrhage at one site may induce a transient increase in blood pressure, causing the rupture of small arteries at other sites, and thus leading to MSIH. Hematoma evacuation and decompression should be conducted in selective cases of MMD-induced MSIH in order to achieve a good prognosis.

Paediatric arterial ischemic stroke: acute management, recent advances and remaining issues

Stroke is a rare disease in childhood with an estimated incidence of 1-6/100.000. It has an increasingly recognised impact on child mortality along with its outcomes and effects on quality of life of patients and their families. Clinical presentation and risk factors of paediatric stroke are different to those of adults therefore it can be considered as an independent nosological entity. The relative rarity, the age-related peculiarities and the variety of manifested symptoms makes the diagnosis of paediatric stroke extremely difficult and often delayed. History and clinical examination should investigate underlying diseases or predisposing factors and should take into account the potential territoriality of neurological deficits and the spectrum of differential diagnosis of acute neurological accidents in childhood. Neuroimaging (in particular diffusion weighted magnetic resonance) is the keystone for diagnosis of paediatric stroke and other investigations might be considered according to the clinical condition. Despite substantial advances in paediatric stroke research and clinical care, many unanswered questions remain concerning both its acute treatment and its secondary prevention and rehabilitation so that treatment recommendations are mainly extrapolated from studies on adult population. We have tried to summarize the pathophysiological and clinical characteristics of arterial ischemic stroke in children and the most recent international guidelines and practical directions on how to recognise and manage it in paediatric emergency.