Childhood moyamoya disease and moyamoya syndrome: a pictorial review

Novel analysis of functional relationship linking moyamoya disease to moyamoya syndrome

Objective

The aim of this study was to elucidate the genetic pathways associated with Moyamoya disease (MMD) and Moyamoya syndrome (MMS), compare the functional activities, and validate relevant related genes in an independent dataset.

Methods

We conducted a comprehensive search for genetic studies on MMD and MMS across multiple databases and identified related genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichments analyses were performed for these genes. Commonly shared genes were selected for further validation in the independent dataset, GSE189993. The Sangerbox platform was used to perform statistical analysis and visualize the results. P＜0.05 indicated a statistically significant result.

Results

We included 52 MMD and 51 MMS-related publications and identified 126 and 51 relevant genes, respectively. GO analysis for MMD showed significant enrichment in cytokine activity, cell membrane receptors, enzyme binding, and immune activity. A broader range of terms was enriched for MMS. KEGG pathway analysis for MMD highlighted immune and cellular activities and pathways related to MMS prominently featured inflammation and metabolic disorders. Notably, nine overlapping genes were identified and validated. The expressions of RNF213, PTPN11, and MTHFR demonstrated significant differences in GSE189993. A combined receiver operating characteristic curve showed high diagnostic accuracy (AUC = 0.918).

Conclusions

The findings indicate a close relationship of MMD with immune activity and MMS with inflammation, metabolic processes and other environmental factors in a given genetic background. Differentiating between MMD and MMS can enhance the understanding of their pathophysiology and inform the strategies for their diagnoses and treatment.

Moyamoya Angiopathy: An Underdiagnosed Cause of Ischemic Stroke in a Tunisian Pediatric Cohort

BACKGROUND

Moyamoya angiopathy is a rare cerebral vasculopathy and an underdiagnosed cause of arterial ischemic stroke in children. We aim to report the clinical and radiological presentations in a Tunisian pediatric cohort.

METHODS

We identified moyamoya angiopathy in pediatric patients managed at the Child Neurology Department of Hedi Chaker Sfax University Hospital between 2008 and 2020 and reviewed their clinical and radiological data as well as their evolutionary profile.

RESULTS

We collected 14 patients with median age 40.6 months and a female predominance (sex ratio of 0.75). An arterial ischemic stroke (AIS) revealed the disease in all patients, with the major symptom being a motor deficit. Symptoms related to a transient ischemic attack before the diagnostic consultation were reported in four patients. Carotid territory was, clinically and radiologically, the most frequently involved. Brain magnetic resonance imaging with angiography was performed in 12 patients confirming the diagnosis by revealing the development of collateral vessels. All the investigations concluded to moyamoya disease in 57.2% and moyamoya syndrome in 42.8%. The latter was related to Down syndrome in five patients and neurofibromatosis type 1 in one patient. With a mean follow-up of 2.35 years, two patients had at least two more AISs during the first two years following diagnosis and 42.8% of patients were diagnosed with vascular or poststroke epilepsy. Full recovery was noted in 14.3% of cases.

CONCLUSIONS

Moyamoya angiopathy in children is a serious condition that needs to be recognized due to the high risk of recurrent ischemic strokes.

Managing the Cerebrovascular Complications of Sickle Cell Disease: Current Perspectives

The importance of protecting brain function for people with sickle cell disease (SCD) cannot be overstated. SCD is associated with multiple cerebrovascular complications that threaten neurocognitive function and life. Without screening and preventive management, 11% of children at 24% of adults with SCD have ischemic or hemorrhagic strokes. Stroke screening in children with SCD is well-established using transcranial Doppler ultrasound (TCD). TCD velocities above 200 cm/s significantly increase the risk of stroke, which can be prevented using chronic red blood cell (RBC) transfusion. RBC transfusion is also the cornerstone of acute stroke management and secondary stroke prevention. Chronic transfusion requires long-term management of complications like iron overload. Hydroxyurea can replace chronic transfusions for primary stroke prevention in a select group of patients or in populations where chronic transfusions are not feasible. Silent cerebral infarction (SCI) is even more common than stroke, affecting 39% of children and more than 50% of adults with SCD; management of SCI is individualized and includes careful neurocognitive evaluation. Hematopoietic stem cell transplant prevents cerebrovascular complications, despite the short- and long-term risks. Newer disease-modifying agents like voxelotor and crizanlizumab, as well as gene therapy, may treat cerebrovascular complications, but these approaches are investigational.

A Retrospective Study on Clinical Features of Childhood Moyamoya Disease

BACKGROUND

Childhood moyamoya disease (MMD) can lead to progressive and irreversible neurological impairment. Early age at onset is likely associated with a worst prognosis of the disease. The study aims to summarize the clinical characteristics of childhood MMD for supporting the diagnosis and treatment of early MMD.

METHODS

A retrospective study was conducted on children aged zero to 16 years who were diagnosed with MMD in the Department of Neurology and neurosurgery of our hospital from October 2016 to April 2020. The clinical characteristics of children with MMD were summarized for analysis, and the distribution of sex and initial attack type among different age groups was determined by data comparison.

RESULTS

The study surveyed 114 children (male to female sex ratio of 1:1.07) with MMD, and 6.1% of them had family history. The mean age of onset was 7.15 ± 3.30 years, and the peak age of onset was five to eight years. The most common initial attack type was transient ischemic attack (TIA) (62 cases, 54.4%) with limb weakness. The incidence of the initial attack type in the three age groups was varied (P < 0.05). The result of overall prognosis was good in 86 cases (89.6%).

CONCLUSIONS

In this study, MMD cases were mainly ischemic type and TIA was the most common initial attack type. Infant group was more prone to have cerebral infarction, whereas preschool and school-age groups tended to have TIA. The treatments and prognosis of the studied MMD cases were achieved with good outcomes.

Comprehensive molecular analyses of an autoimmune-related gene predictive model and immune infiltrations using machine learning methods in moyamoya disease

Background: Growing evidence suggests the links between moyamoya disease (MMD) and autoimmune diseases. However, the molecular mechanism from genetic perspective remains unclear. This study aims to clarify the potential roles of autoimmune-related genes (ARGs) in the pathogenesis of MMD. Methods: Two transcription profiles (GSE157628 and GSE141025) of MMD were downloaded from GEO databases. ARGs were obtained from the Gene and Autoimmune Disease Association Database (GAAD) and DisGeNET databases. Differentially expressed ARGs (DEARGs) were identified using "limma" R packages. GO, KEGG, GSVA, and GSEA analyses were conducted to elucidate the underlying molecular function. There machine learning methods (LASSO logistic regression, random forest (RF), support vector machine-recursive feature elimination (SVM-RFE)) were used to screen out important genes. An artificial neural network was applied to construct an autoimmune-related signature predictive model of MMD. The immune characteristics, including immune cell infiltration, immune responses, and HLA gene expression in MMD, were explored using ssGSEA. The miRNA-gene regulatory network and the potential therapeutic drugs for hub genes were predicted. Results: A total of 260 DEARGs were identified in GSE157628 dataset. These genes were involved in immune-related pathways, infectious diseases, and autoimmune diseases. We identified six diagnostic genes by overlapping the three machine learning algorithms: CD38, PTPN11, NOTCH1, TLR7, KAT2B, and ISG15. A predictive neural network model was constructed based on the six genes and presented with great diagnostic ability with area under the curve (AUC) = 1 in the GSE157628 dataset and further validated by GSE141025 dataset. Immune infiltration analysis showed that the abundance of eosinophils, natural killer T (NKT) cells, Th2 cells were significant different between MMD and controls. The expression levels of HLA-A, HLA-B, HLA-C, HLA-DMA, HLA-DRB6, HLA-F, and HLA-G were significantly upregulated in MMD. Four miRNAs (mir-26a-5p, mir-1343-3p, mir-129-2-3p, and mir-124-3p) were identified because of their interaction at least with four hub DEARGs. Conclusion: Machine learning was used to develop a reliable predictive model for the diagnosis of MMD based on ARGs. The uncovered immune infiltration and gene-miRNA and gene-drugs regulatory network may provide new insight into the pathogenesis and treatment of MMD.

Acute ischemic stroke secondary to ventriculoperitoneal shunt dysfunction in a child with Moyamoya syndrome

Background:

Patients with brain vascular disease and hydrocephalus may be predisposed to acute ischemic stroke in case of shunt dysfunction and subsequent increased intracranial pression. Patients with brain tumor may develop hydrocephalus as a consequence of obstruction of cerebrospinal fluid pathways and radiation-induced moyamoya syndrome secondary (RIMS) to radiotherapy (RT).

Case Description:

A 15-year-old male patient, affected by hydrocephalus and RIMS, presented acute cerebral ischemia after an episode of shunt malfunction. The shunt was promptly revised and the areas of ischemia visible at magnetic resonance imaging significantly decreased.

Conclusion:

Children who receive RT for brain tumor, particularly if the circle of Willis region is involved, require close surveillance for the development of vasculopathy and consequent stroke. This surveillance must be even tighter if the patient has been treated with ventricular shunt for the possible synergistic interaction between the two causes on reducing cerebral perfusion and increasing the risk of acute ischemic events.

Cerebrofacial vascular metameric syndrome associated with Moyamoya syndrome: a rare case report

INTRODUCTION

Neural crest and mesoderm cell dysfunction of certain metameric level result in vascular malformations, i.e., cerebrofacial arteriovenous metameric syndrome (CAMS) and cerebrofacial venous metameric syndrome (CVMS). Moyamoya disease is a progressive steno-occlusive disease in the terminal portions of the bilateral internal carotid artery. The patient in this case report was a child with cerebrofacial vascular metameric syndrome, associated with moyamoya syndrome.

CASE REPORT

Child, 7 months old, female, admitted to the emergency department with seizures, hemangioma on the right half of the face (forehead, upper eyelid, and upper lip), and left hemiparesis. The magnetic resonance imaging of the skull indicated increased myelination in the right hemisphere (T2) and atrophy compatible with Sturge-Weber syndrome. Cerebral angiography indicated vasculopathy with bilateral moyamoya pattern, associated with other arteriovenous malformations compatible with cerebrofacial vascular metameric syndrome. Moyamoya syndrome was treated with indirect revascularization (pial synangiosis) achieving good outcomes.

DISCUSSION

Vascular malformations can involve the orbits, face, and brain simultaneously. CAMS with forebrain or hindbrain involvement can be classified into subgroups: I, II, and III. On the other hand, venous malformations in Sturge-Weber syndrome or encephalotrigeminal angiomatosis can be considered CVMS. Moyamoya disease is called syndrome when related to another clinical condition, such as the present case, i.e., neurocutaneous Sturge-Weber syndrome. The association of chronic moyamoya vasculopathy with cerebrofacial vascular metameric syndrome is rare. Further studies are required to establish the best treatment approach.

Multiple Burr-Hole Surgery for the Treatment of Moyamoya Disease and Quasi-Moyamoya Disease in Children: Preliminary Surgical and Imaging Results

OBJECTIVE

Moyamoya disease (MMD) is characterized by a progressive spontaneous occlusion of distal internal carotid arteries and its main branches. It is necessary to promptly diagnose and treat this condition, especially in children, because of the high risk of stroke and consequent severe disability. In this study, we examine the role of multiple burr-hole surgery (MBHS) in the treatment of pediatric patients with MMD and quasi-MMD and the role of perfusion magnetic resonance imaging (MRI) in the surgical indication and during follow-up.

METHODS

We reviewed preoperative, early postoperative, and late postoperative MRI perfusion and digital subtraction angiography images together with clinical and surgical outcomes in 10 children with MMD treated by MBHS.

RESULTS

Fourteen MBHS procedures (6 unilateral, 2 bilateral, and 2 single-setting bilateral) were performed in 10 children. Clinical and radiologic follow-up for all patients ranges from 16 months to 7 years. No ischemic events (transient ischemic attacks or stroke) occurred during the follow-up period. Postoperative digital subtraction angiography showed good revascularization around the burr-hole sites in all patients. The functional efficacy of the surgery was confirmed by dynamic susceptibility contrast perfusion MRI studies in 8 patients.

CONCLUSIONS

Our data underline the good rate of success of MBHS in pediatric MMD and quasi-MMD. This technique results in good collateral revascularization, improved cerebral perfusion and excellent short and long-term symptoms control, with low perioperative risk. Postoperative changes of perfusion parameters and ivy sign MRI finding seem to show a positive correlation and mainly occur in posterior middle cerebral artery territory.

Radiation-Induced Moyamoya Syndrome After Proton Therapy in Child with Clival Chordoma: Natural History and Surgical Treatment

BACKGROUND

Proton therapy has proven to be effective and safe in the treatment of radioresistant skull base tumors such as chordomas. Thanks to the peculiar physical properties of the proton beam, radiation energy is delivered in a narrow space called the Bragg peak and the surrounding normal tissues receive a minimal amount of the radiation dose. This is important to lower the risk of radiation-induced damage, especially in children. However, local adverse effects in proximity to the target volume may occur. In particular, the development of moyamoya syndrome (MMS) has been rarely reported in children receiving proton beam therapy for brain tumors.

CASE DESCRIPTION

We report on a child who developed rapidly progressive MMS after proton beam therapy for a clivus chordoma. A combined indirect revascularization procedure by encephalo-duro-arterio-synangiosis and encephalo-myo-synangiosis was performed with good neuroradiologic and clinical outcome.

CONCLUSIONS

Regardless of the presence of known risk factors for MMS, strict neuroimaging surveillance is indicated in all patients treated with radiotherapy including those receiving proton beam therapy. We suggest that an early revascularization procedure should be considered in patients with worsening symptoms and/or sign of neuroradiologic progression of cerebral vasculopathy. This management of MMS could lower the risk of permanent neurologic deficits and improve patients' quality of life.

Moyamoya syndrome in a pediatric patient with congenital human immunodeficiency virus type 1 infection resulting in intracranial hemorrhage

In the era of Antiretroviral Therapy (ART) in which human immunodeficiency virus type 1 (HIV-1) infection affected children can expect a better prognosis, the importance of careful follow up of pediatric HIV-1 cases for neurological complications has been growing. We present a case of hemorrhagic Moyamoya syndrome in a child with congenital HIV-1 infection. A 10-year-old girl was referred to our hospital for the treatment of Pneumocystis Jirovecii Pneumonia (PCP: Pneumocystis pneumonia). Her HIV-1 control was poor and Moyamoya syndrome was found during the opportunistic infection screening at admission. Despite subsequent successful treatment of PCP and HIV-1 infection, we could not save her life due to the intracranial hemorrhage caused by Moyamoya syndrome. A few reported cases of Moyamoya syndrome associated with HIV-1 infection have shown negative outcomes when the control of HIV-1 infection is unsuccessful. Recently "HIV-associated vasculopathy" has been used to describe the cerebrovascular disorder related to HIV-1 infection that is caused by the endothelial dysfunction induced from chronic inflammation and cytokine imbalances due to HIV-1 infection. We assumed that "HIV-associated vasculopathy" may have contributed to the development of collateral vessels impairment related to the bleeding, although the mechanism of vascular damage with HIV-1 infection is not yet well defined. Therefore proper management of the HIV-1 infection is crucial for Moyamoya syndrome with HIV-1 cases. Furthermore it is better to take into account the risk of intracerebral hemorrhage when considering the indication and timing of the revascularization surgery, although generally hemorrhaging is rare in Moyamoya disease in children.

Magnetic Resonance Imaging (MRI) and Digital Subtraction Angiography Investigation of Childhood Moyamoya Disease

Because digital subtraction angiography (DSA) is not an ideal angiographic examination for moyamoya disease in the pediatric population, magnetic resonance angiography (MRA) provides a noninvasive contrast-free angiographic examination; whereas magnetic resonance imaging (MRI) provides superior spatial resolution and soft-tissue contrast for lesion assessment. Ninety patients with moyamoya disease were examined by MRI and DSA to assess the distribution of lesions and their diagnostic agreement between modalities. MRI examination revealed 439 lesions. Punctate lesions were the most abundant, followed by patchy lesions. These lesions generally covered a smaller area than the abnormal-vascular corresponding brain parenchyma. Steno-occlusive changes at bilateral anterior, medial, and posterior cerebral arteries were identified by MRA and DSA. MRI showed moderate agreement in identifying lesions after steno-occlusive changes in anterior and medial cerebral arteries, and good agreement in posterior cerebral arteries; 6% to 11% of cases were misdiagnosed by MRA.

Moyamoya Syndrome Associated With Hereditary Spherocytosis: An Emerging Clinical Entity

Moyamoya syndrome is an unusual cerebrovascular disorder, which has rarely been reported in association with hereditary spherocytosis. We present the case of a 6-year-old boy with hereditary spherocytosis who was diagnosed with Moyamoya syndrome following a stroke. We discuss why these conditions may coexist and briefly outline the management of such children.

Encephaloduroarteriosynangiosis (EDAS) in young patients with cerebrovascular complications of sickle cell disease: Single-institution experience

Moyamoya syndrome occurs in sickle cell disease (SCD) as a secondary complication of large-artery stenosis. Moyamoya increases the risk of stroke, but its optimal management in SCD is not established.  Encephaloduroarteriosynangiosis (EDAS) is a neurosurgical revascularization procedure for moyamoya whose use has been reported in SCD patients. We report the outcomes of 11 patients with SCD systematically evaluated for EDAS by a multidisciplinary team and compare the rate of stroke in patients who received EDAS to those who did not. Moyamoya syndrome was diagnosed by flow abnormalities on magnetic resonance angiography at median age of 8.2 years. Four patients deferred surgery. Seven patients underwent EDAS at median age of 19 years. There were no intraoperative complications, perioperative strokes, or deaths. Transient postoperative complications occurred in six cases (86%). On follow-up, three patients (43%) had no evidence of flow in their EDAS grafts, and one later developed a hemorrhagic stroke. Five EDAS patients (71%) had radiographically stable vasculopathy. Compared to the four patients who deferred surgery, the incidence of stroke in EDAS group was no different. The optimal use of EDAS in patients with SCD-associated moyamoya syndrome requires further investigation by a prospective, controlled clinical trial.

Ultrasonographic Changes after Indirect Revascularization Surgery in Pediatric Patients with Moyamoya Disease

The marked cerebral hypoperfusion of moyamoya disease (MMD) can be treated with encephaloduroarteriosynangiosis (EDAS), an indirect revascularization surgery. Collateral establishment after the surgery is a gradual process; thus, easy access to serial assessment is of great importance. We prospectively recruited 15 pediatric moyamoya patients who underwent EDAS surgeries on a total of 19 hemispheres. Ultrasonography of extracranial and intracranial arteries was performed pre-operatively and post-operatively at 1, 3 and 6 mo. Among the extracranial arteries, the superficial temporal artery had the most pronounced increase in flow velocity and decrease in flow resistance from 1 mo post-surgery (p < 0.01). Among the large intracranial arteries, a significant increase in peak systolic velocity was observed in the anterior cerebral artery from 3 mo post-surgery (p < 0.05). These findings indicate significant hemodynamic changes on ultrasonography in pediatric moyamoya patients after indirect revascularization surgery.

Moyamoya disease: impact on the performance of oral and written language

Moyamoya disease is an unusual form of occlusive, cerebrovascular disorder that affects the arteries of the central nervous system, causing acquired language alterations and learning difficulties. The study aim was to describe the oral/written language and cognitive skills in a seven-year-and-seven-month-old girl diagnosed with Moyamoya disease. The assessment consisted of interviews with her parents and application of the following instruments: Observation of Communicative Behavior, Peabody Picture Vocabulary Test, Academic Performance Test, Profile of Phonological Awareness, Raven's Progressive Matrices Test, Special Scale, Wechsler Intelligence Scale for Children, Bender Visual Motor Gestalt Test, and Wisconsin Card Sorting Test. Two episodes of stroke in the left and right temporal-parietal and left frontal areas occurred until the age of six years and five months. Revascularization surgery and medication treatment were conducted. The audiologic and ophthalmologic assessments indicated normality. At the time of the study, the girl was attending the second grade of elementary school. She presented changes in oral and written language (syllabic-alphabetic), non-naming of all graphemes, low arithmetic and writing means, reading skill below first grade level and psycholinguistic delay, and pre-school level phonological processing skills. The psychological evaluation indicated satisfactory intellectual level; however, it also showed cognitive performance impairment in verbal and execution tasks and limitations on graphic-perceptual-motor skills and sequential logic organization. The stroke episodes influenced the performance of learning processes, affecting the analysis, integration, and interpretation of relevant visual and auditory information.

Early-onset stroke with moyamoya-like syndrome and extraneurological signs: a first reported paediatric series

BACKGROUND

Moyamoya syndrome is characterised by an occlusion of the carotid terminations with the development of collateral vessels. Our objective is to describe a series of infants presenting early-onset moyamoya-like syndrome, which may constitute a distinct entity.

METHODS

From a cohort of children with rare cerebral vascular pathologies, we studied eight infants (28 days-1 year) with early-onset moyamoya-like syndrome demonstrated by angiography. We retrospectively analysed the patterns on MRI and MRA, as well as all other available data.

RESULTS

Median age at diagnosis was 7 months (IQR: 6-8) with arterial ischaemic stroke in the middle cerebral artery territory. All of the children experienced severe stroke recurrence within a median time of 11 months (IQR: 10-12), and all showed extraneurological symptoms. The anterior cerebral circulation was involved in all cases and the posterior circulation was involved in six. Two children died and all of the other children suffered permanent neurological deficits.

CONCLUSIONS

The presence of extraneurological signs in cases of early-onset moyamoya syndrome is suggestive of a newly described systemic vasculopathy with predominantly cerebrovascular expression. Given its rapid progression marked by severe recurrent strokes and poor clinical outcome, early diagnosis could help in the decision to institute aggressive therapy.

Atypical presentation of moyamoya disease in an infant with a de novo RNF213 variant

Variants in RNF213 lead to susceptibility to moyamoya disease, a rare cerebral angiopathy characterized by bilateral stenosis of the internal carotid arteries and development of a compensatory collateral network. We describe a 3-month-old female with seizures, arterial narrowing involving the internal carotid and intracranial arteries and inferior abdominal aorta, and persistently elevated transaminases. Whole exome sequencing demonstrated a novel de novo variant in RNF213, securing a molecular diagnosis and directing appropriate intervention. This report underscores the role of whole exome sequencing in cases for which a complex and atypical presentation may mask diagnosis. Furthermore, the early and severe presentation in our patient, in conjunction with a novel de novo RNF213 variant, suggests that specific variants in RNF213 may lead to a Mendelian form of disease rather than simply conferring susceptibility to multifactorial disease.

Research Progress of Moyamoya Disease in Children

During the onset of Moyamoya disease (MMD), progressive occlusion occurs at the end of the intracranial internal carotid artery, and compensatory net-like abnormal vessels develop in the skull base, generating the corresponding clinical symptoms. MMD can affect both children and adults, but MMD in pediatric patients exhibits distinct clinical features, and the treatment prognoses are different from adult patients. Children are the group at highest risk for MMD. In children, the disease mainly manifests as ischemia, while bleeding is the primary symptom in adults. The pathogenesis of MMD in children is still unknown, and some factors are distinct from those in adults. MMD in children could result in progressive, irreversible nerve functional impairment, and an earlier the onset corresponds to a worse prognosis. Therefore, active treatment at an early stage is highly recommended. The treatment methods for MMD in children mainly include indirect and direct surgeries. Indirect surgeries mainly include multiple burr-hole surgery (MBHS), encephalomyosynangiosis (EMS), and encephaloduroarteriosynangiosis (EDAS); direct surgeries mainly include intra- and extracranial vascular reconstructions that primarily consist of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. Indirect surgery, as a treatment for MMD in children, has shown a certain level of efficacy. However, a standard treatment approach should combine both indirect and direct procedures. Compared to MMD in adults, the treatment and prognosis of MMD in children has higher clinical significance. If the treatment is adequate, a satisfactory outcome is often achieved.

The collateral circulation in pediatric moyamoya disease

PURPOSE

The descriptions of collateral circulation in moyamoya have so far been a mixture of topography-based and vessels' source-based analyses. We aimed to investigate the anatomy and systematize the vascular anastomotic networks in pediatric moyamoya disease.

METHODS

From a series of 25 consecutive complete angiographic studies of newly diagnosed children with moyamoya, 14 children had moyamoya disease and 11 were diagnosed with moyamoya syndrome, i.e., moyamoya angiopathy with some additional concomitant systemic disease. We retrospectively analyzed the arterial branches supplying the moyamoya anastomotic networks, their origin, course, location, and connections with the recipient vessels.

RESULTS

We describe four types of anastomotic networks in children with moyamoya disease, two superficial-meningeal and two deep-parenchymal. As superficial-meningeal, we defined the leptomeningeal and the durocortical networks. Apart from the previously described leptomeningeal network observed in the convexial watershed zones, we report on the basal temporo-orbitofrontal leptomeningeal network. The second superficial-meningeal network is the durocortical network, which can be basal or calvarian in location. We define as deep-parenchymal networks the nonpreviously described subependymal network and the inner striatal and inner thalamic networks. The subependymal network is fed by the intraventricular branches of the choroidal system and diencephalic perforators, which at the level of the periventricular subependymal zone, anastomose with medullary-cortical arteries as well as with striatal arteries. The inner striatal and thalamic networks are constituted by intrastriatal connections among striatal arteries and intrathalamic connections among thalamic arteries when the disease compromises the origin of one or more sources of their supply.

CONCLUSION

The previously inexplicitly described "moyamoya abnormal network" in pediatric moyamoya disease can be described as a composition of four anastomotic networks with distinct angioarchitecture. A better understanding of the collateralization in moyamoya may help in defining a new staging system of the disease with clinical relevance.

Characteristics of brain magnetic resonance images at symptom onset in children with moyamoya disease

OBJECTIVES

To clarify the characteristics of brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) at symptom onset in patients with childhood moyamoya disease (MD) according to developmental stage.

METHODS

In 26 childhood MD patients who underwent brain MRI and MRA within 3 months from symptom onset, MRA scores and grades and MRI findings from symptomatic hemispheres were summarized according to developmental stage: infancy (0-1 years, three patients), toddlerhood/preschool age (2-5 years, nine patients), school age (6-10 years, seven patients), and adolescence (11-18 years, seven patients).

RESULTS

Mean MRA score was 5.6, which was higher in adolescents (6.9). The most common MRA grade was grade 3, particularly in those under 10 years. Acute ischemic infarction presented in 17 patients (65%), was more common in patients below 5 years (83%) and was mainly in a gyral pattern (47%). Most hemorrhagic infarctions occurred in adolescents. Moyamoya vessels in the Sylvian valleys were apparent in 22 patients (85%), which were the most sensitive non-ischemic findings on T2 weighted images. The signal void in the distal internal carotid artery was diminished in 73% and apparent signal voids in basal ganglia were seen in three patients. The ivy sign was positive in 81% on fluid attenuated inversion recovery images and 69% on contrast-enhanced T1-weighted images in 21 and 16 patients, respectively.

CONCLUSIONS

Brain MRIs and MRAs at symptom onset in childhood MD have characteristic findings, which differ in different developmental stage.

Patterns of cerebral ischemia in children with moyamoya

BACKGROUND

Moyamoya disease is characterized by progressive cerebrovascular stenosis with recurrent cerebral ischemic events. Transient ischemic attacks are often associated with hyperventilation in children with moyamoya, suggesting hypoperfusion rather than thrombotic vaso-occlusion as a prominent mechanism. The patterns of ischemia and severity of steno-occlusive disease in such children may elucidate these mechanisms.

METHODS

Children, 1 month to 18 years, with moyamoya, observed over 11 years were analyzed. A study neuroradiologist reviewed all presurgical neuroimaging. Ischemic injury was categorized into cortical, subcortical, and watershed infarction. Angiographic findings were staged using a standardized method.

RESULTS

Twenty children, 15 girls, median age 6.4 years, were included. All children had magnetic resonance imaging and angiography, and in 16, conventional angiography was available. All 40 hemispheres, in 20 children, were evaluated. The initial clinical presentation included neurological deficits in 17, recurrent transient ischemic attacks in 7, headache in 8, seizures in 8, and alteration in consciousness in 4 children. Infarcts were bilateral in 13 (65%) children (ischemia alone in 14, ischemic stroke with hemorrhagic transformation in two, and primary hemorrhage in two). Infarcts were cortical and/or subcortical in 13 (65%), both deep and cortical watershed in 11 (55%), and cortical watershed alone in 5 (25%) children. The predominant vascular territory involved was the middle cerebral artery. The internal carotid arterial system was involved in all, with stage IV being the most frequent angiographic stage.

CONCLUSIONS

Ischemic injury in deep watershed zones is common in childhood moyamoya and may reflect non-vaso-occlusive ischemic mechanisms. Location and severity of vascular involvement may correlate with various patterns of ischemic infarction in moyamoya disease and requires further study.

Selective and superselective angiography of pediatric moyamoya disease angioarchitecture: the anterior circulation

The angioarchitecture of the so-called moyamoya vessels in children has not been explicitly analyzed. We aimed to investigate the precise anatomy of the vascular anastomotic networks in patients with childhood moyamoya disease. Six children diagnosed with moyamoya disease for the first time underwent an angiographic investigation with selective and superselective injections. We recorded the arterial branches feeding the moyamoya anastomotic networks, their connections and the recipient vessels. Depending on the level of the steno-occlusive lesion, the feeding vessels included the medial striate arteries, the perforators of the choroidal segment of the carotid, the uncal artery, the medial and lateral branches of the intraventricular segment of the anterior choroidal artery, perforators of the communicating segment, the superior hypophyseal arteries, the prechiasmal branches of the ophthalmic artery, the ethmoidal arteries and the dural branches of the cavernous carotid. Through connections, which are described, the recipient vessels were the lateral striate arteries and the middle cerebral, the medial striate arteries and the anterior cerebral, medullary arteries around the ventricular system, anterior temporal branches of the middle cerebral, orbitofrontal and frontopolar branches of the anterior cerebral, as well as other cortical branches of the anterior and middle cerebral territories. The use of high quality selective and superselective angiography enabled us to clearly demonstrate for the first time aspects of the microangiographic anatomy of the moyamoya anastomotic network previously only vaguely or incompletely described.

Selective neuropsychological impairments and related clinical factors in children with moyamoya disease of the transient ischemic attack type

PURPOSE

Moyamoya disease is characterized by progressive narrowing of bilateral internal carotid arteries. Neuropsychological impairments are suspected due to frequent involvement of the frontotemporal areas. The present study thus aimed to investigate the pattern of neuropsychological function in children diagnosed with moyamoya disease.

METHODS

Thirteen children with moyamoya disease of the transient ischemic attack type received standardized neuropsychological tests that evaluate general intellectual function, verbal comprehension, perceptual organization, working memory, processing speed, episodic memory, category fluency and visuospatial function. Related clinical factors were also analyzed.

RESULTS

The results showed single-domain cognitive impairment in around 15 % of patients and multiple-domain cognitive impairments in 23 % of patients. Selective impairments of episodic memory and processing speed were especially noted in those with younger age of onset and prolonged symptom duration.

CONCLUSIONS

Neuropsychological impairments are not infrequent in children with moyamoya disease despite normal general intellectual functioning. The pattern of cognitive dysfunction is often associated with lesions in frontotemporal areas. Early detection and intervention shall be considered regarding cognitive outcome in pediatric group.

Long-term Outcome of Motor Function in a Child with Moyamoya Disease: A Case Report

[Purpose] This observational study provides a retrospective description of changes in motor function of a 10 year old child who suffered from motor weakness caused by Moyamoya disease (MMD) over an approximately 3 year follow-up observation period. [Methods] The child was diagnosed as MMD due to multifocal encephalomalacia in both frontal and parietal cortices. After the ischemic attack, the child received physical therapy the based on stroke rehabilitation, including muscle strengthening exercises, training of functional activity/ADL, and neurodevelopmental treatment. [Results] The child’s MRI showed areas of ischemic infarction in both the frontal and parietal lobes. Steno-occlusive findings for both the anterior cerebral artery and middle cerebral artery were observed on cerebral angiography. Regarding changes of motor function during the three-year follow-up, significant improvements, in the Motricity index, Modified Brunnstrom Classification, manual function test, and functional ambulatory category were observed. [Conclusion] The basic motor function and functional abilities of the child showed improvement with conservative treatment over approximately three years. The functional motor ability of children with MMD may be similar to the recovery progression of pediatric stroke patients, if there is no re-occurrence of ischemia.

Early clinical characteristics according to developmental stage in children with definite moyamoya disease

The objective is to clarify the early clinical characteristics in childhood moyamoya disease (MD). Epidemiologic characteristics, symptoms and diagnostic rates were assessed in 64 children (0-18 years) with definite MD according to developmental stage: infancy (5; 0-1 years); toddlerhood/preschool age (22; 2-5 years); school age (29; 6-10 years); and adolescence (8; 11-18 years). The median ages at onset was 6.25 years and the female to male ratio was 1.9 (~2.5 in toddlerhood/preschool age and in adolescence, P=0.71). Previous headache was observed in 23% (14/64): frequently in school age (38%, P=0.02) and within 6 months before main symptoms (6/11). As an initial symptom, weakness was observed in 78% (50/64) mainly as transient ischemic attack (TIA, 61%) in limbs (90%) and unilaterally (82%). TIA was less frequent in infancy (40%, P=0.04). Seizure was observed in 27% (17/64): frequently in infancy (100%, P<0.01), as the focal type (71%), and in the right extremity (3:1). Isolated seizures without other symptoms was frequent in children ~5 years (P<0.01). Severe headache associated with MD was observed in 14% (9/64). Provoking events were positive in 42% (27/64): in school age, frequently during eating (28%); and in toddlerhood/preschool age, during crying (27%). The diagnostic rates at 3 and 12 months from symptom-onset were 39% (80% during infancy vs. 28% in school age, P=0.14) and 67%, respectively. Symptomatic progression at diagnosis was observed in 38% (24/64). Initial clinical characteristics in childhood definite MD differed according to developmental stage and from at diagnosis.

Caucasian familial moyamoya syndrome with rare multisystemic malformations

Moyamoya disease is an idiopathic progressive steno-occlusive disorder of the intracranial arteries located at the base of the brain. It is associated with the development of compensatory extensive network of fine collaterals. Moyamoya disease is considered syndromic when certain genetic or acquired disorders such as polycystic kidney disease, neurofibromatosis, or meningitis are also present. Although the genetic contribution in moyamoya is indisputable, its cause and pathogenesis remain under discussion. Herein, we report a rare occurrence of moyamoya syndrome in two European Caucasian siblings in association with unusual multisystemic malformations (polycystic kidney disease in one, and intestinal duplication cyst in the other). The karyotype was normal. No mutation in the RFN213 gene was found, and none of the HLA types linked to moyamoya disease or described in similar familial cases were identified. By describing these multisystemic associations, polycystic kidney disease for the second time, and intestinal malformation for the first time in the literature, our report expands the phenotypic variability of moyamoya syndrome. The coexistence of disparate malformations among close relatives suggests an underlying common genetic background predisposing to structural or physiological abnormalities in different tissues and organs.

Moyamoya vascular pattern in Alagille syndrome

We describe a girl with Alagille syndrome and a moyamoya angiographic pattern on magnetic resonance angiography. She was referred for genetic consultation because of posterior embryotoxon and peripheral pulmonary stenosis. Her facial appearance was typical, but she had no cholestasis or vertebral involvement. A heterozygous duplication of one nucleotide (a c.715dupA mutation) not previously described was identified in exon 5 of the JAG1 gene. We review similar cases in the literature and possible pathophysiologic mechanisms (e.g., the Jagged 1 and Notch signaling pathway) of this association.