Moyamoya Patients Research Articles

Abstract WP156: Moyamoya Syndrome - Comparison of Long Term Outcome of Conservative and Surgical treatment in India.

Background: Revascularization surgery (RS) is the therapy of choice in Moyamoya disease (MMD). Due to rarity of disease and ethical concerns, randomized controlled trials about the treatment options are lacking. Very little information is available on the outcome of conservatively treated moyamoya patients. Aim: We compared the long term outcome of moyamoya patients treated conservatively to those who underwent RS. Methods: Our study population included all patients with moyamoya from 2002-2012. The demographic and clinical characteristics were obtained by retrospective chart review. The imaging details were reviewed. The follow-up information and outcome were obtained prospectively. Results: Of the 36 patients, 26( 72.2%) had MMD and 10 ( 27.8 %) had moyamoya syndrome. Of the patients with moyamoya syndrome, 6 had a well recognized risk factors( 2-Downs syndrome,1-Neurofibromatosis,2- atherosclerosis,1-vasculitis) and 4 had unilateral disease. The median age at onset of symptoms was 17.5years (range,10 months- 55 years). Fifteen patients belonged to pediatric group and 21 were adults. All the paediatric patients had ischemic events at onset and 10 (47.6 %) of the adults presented with haemorrhage. Twenty (55.6%) patients received conservative treatment and 16(44.4 %) underwent revascularization procedures. The median duration of follow-up was 28 months (range,3-90 months). Two of the surgically treated patients had recurrent ischemic events on follow up, but none of the conservatively treated patients had events. An excellent outcome (Modified rankin scale of ≤ 2) was seen in 12 (75%) of surgically treated patients and all of the conservatively treated patients. Of the 4 patients in the surgically treated group with poor outcome, one was due to recurrent stroke ,one due to postoperative stroke and 2 had severe stroke at onset. Conclusion: Compared to East Asians, our patients had a lower stroke recurrence rate and better functional outcome even with conservative treatement. The impact of RS in modifying the patients clinical course in Indian patients is difficult to evaluate. Future studies should focus on clinical and imaging predictors of progression to select moyamoya patients for RS.

Abstract TP157: Clinical Significance of the Ivy Sign on FLAIR MRI in Moyamoya Disease

Background and purpose: Leptomeningeal collateral is well developed in patient with moyamoya disease, and it appears as high signal intensity (Ivy sign) on FLAIR images. Some studies reported correlations between Ivy sign and cerebral vascular reserve, but the clinical meaning of Ivy sign is still uncertain. Therefore, we aimed to investigate the clinical significance of Ivy sign in moyamoya disease. Methods: FLAIR images of 87 patients with moyamoya disease were reviewed by two neurologists blinded to any clinical information. In order to decide dominant hemisphere with Ivy sign, we divided cerebral hemisphere into 4 regions from anterior to posterior, and each region was scored (0-3 point) based on the prominence of Ivy sign. Clinical findings were obtained by retrospective chart reviews. Results: Ivy sign was observed in all moyamoya patients. The score of patients with nonspecific symptom was lower than the patients with complete stroke (4.88±2.85 vs 7.85±3.54, p=0.045). The score was lower in mild symptom group (nonspecific symptom or single event of TIA) than the severe symptom group (recurrent TIA or complete stroke) (6.38±0.90 vs 7.83±0.43, p=0.045). Dominant hemispheric Ivy sign (IDH) could be determined in 79 patients and 58 patients of them had lateralizing symptom. The side of IDH was significantly correlated with side of symptoms (p=0.002). Twenty-nine patients of 37 with right IDH (78.4%) had clinical symptom on the left side, and 13 out of 21 with left IDH (61.9%) was symptomatic on the right side. Ischemic or hemorrhagic lesions were detected on MRI in 50 patients and 10 patients of them had bilateral lesions of similar size. The side of IDH was correlated with the side of MRI lesion (p=0.036). Conclusions: Ivy sign was detected in all patients with moyamoya disease. Since the sign was highly correlated with clinical findings, more prominent sign may suggest more frequent and severe clinical events. Ivy sign can be utilized as a means of determining treatment option and predicting clinical outcome.

Prevalence and Characteristics of Concurrent Down Syndrome in Patients With Moyamoya Disease

An association between moyamoya disease and Down syndrome appears to exist on the basis of reported anecdotal cases in the literature. To determine the prevalence of Down syndrome associated with moyamoya disease in inpatients and to identify the demographic and clinical features of moyamoya disease that may be unique when associated with Down syndrome. In this observational study, we analyzed data from the Nationwide Inpatient Sample between 2002 and 2009 using International Classification of Diseases codes for moyamoya disease and Down syndrome for patient identification. Data including patient age, sex, race/ethnicity, secondary diagnosis, procedures, hospital costs, and patient outcomes were obtained. From 2002 to 2009, an estimated 518 patients (mean ± SD age, 16.2 ± 1.68 years) with coexisting moyamoya disease and Down syndrome were admitted. The estimated prevalence was 3.8% (3760 per 100,000) among patients admitted with moyamoya disease and 9.5% (9540 per 100,000) among moyamoya patients < 15 years of age. Patients admitted with moyamoya disease and Down syndrome were most frequently white and Hispanic (P = .02). They were more likely to present with ischemic stroke and less commonly with hemorrhagic stroke (15.3% and 2.7%, respectively; P < .05). This is the first study to estimate the prevalence of Down syndrome in patients with moyamoya disease. The 26-fold-greater prevalence of Down syndrome in patients with coexisting moyamoya disease compared with the prevalence of Down syndrome among live births (145 per 100,000) highlights the need for a better understanding of the common pathophysiology of the 2 conditions.

Abstract TP149: Moyamoya Disease in Pregnancy: Protective Effect of Cerebral Revascularization via Pial Synangiosis

Introduction: Pregnancy, labor and delivery may lead to hemodynamic changes that could cause neurologic complications in patients with moyamoya disease (MMD). We reviewed an operative series of moyamoya patients treated by pial synangiosis from 1985 to 2012 to identify those patients who became pregnant in an attempt to determine the safety of pregnancy in this group of patients. Methods: Clinical and radiographic records of all adult moyamoya patients treated at a single institution from 1985 to 2012 were retrospectively reviewed. Results: From 1985-2012, 8 pial synangiosis surgeries were performed on 5 women with moyamoya disease before or during pregnancy. The mean age at surgery was 16.2. Four patients presented with stroke and one with transient ischemic attacks. Pre-operative Suzuki grade was III or higher in all treated hemispheres. Post-operative angiogram was available in 3 patients (5 treated hemispheres), and all demonstrated good collateral formation (Matsushima grade A or B). Clinical follow-up was available for an average of 13.0 years (range 1-22.0 years). The mean duration from surgery to delivery was 9.4 years; one patient was diagnosed with MMD during pregnancy and was operated at 4 months gestation. All women experienced successful pregnancy outcome: three had normal vaginal delivery and two underwent Caesarean section. Post-pregnancy stroke occurred on the contralateral hemisphere in one patient originally treated with unilateral moyamoya. This patient was found to have developed MMD on the other hemisphere and underwent additional revascularization. No other complications were observed during the follow-up period. Conclusions: Women with moyamoya disease can go through pregnancy safely and successfully after adequate cerebral revascularization.

Abstract TMP42: Treatment of Moyamoya Disease in the Adult Population with Pial Synangiosis

Introduction: Surgical treatment of moyamoya disease in the adult population commonly employs direct revascularization, the superficial temporal artery to middle cerebral artery (STA-MCA) bypass. Pial synangiosis, a method of indirect revascularization, has been utilized in adult moyamoya patients when STA-MCA bypass is not technically feasible. Although the effectiveness of pial synangiosis has been well described in children, only limited reports have examined its role in adult moyamoya patients. Here we report on our experience with pial synangiosis revascularization for this population. Methods: We reviewed the clinical and radiographic records of all adult moyamoya patients (18 years of age or older), who underwent cerebral revascularization surgery using pial synangiosis at a single institution. Results: From 1985-2010, 66 procedures (6 unilateral, 30 bilateral) were performed on 36 adult moyamoya patients. The mean age at surgery was 28.3 (range: 19 - 51) and 30 were female. Thirty-one patients (86.1%) presented with either stroke or TIA and 3 (8.3%) with hemorrhage. Pre-operative Suzuki grade was III or higher in 50 hemispheres (75.7%) and 3 patients had prior treatments to the affected hemisphere before pial synangiosis surgery. Clinical follow-up was available for an average of 5.8 years (range 0.6-14.1 years), with 26 (72.2%) patients followed for longer than 2 years. Post-operative angiogram was available for 24 patients and 46 revascularized hemispheres, and 39 (84.8%) demonstrated good collateral formation (Matsushima grade A or B). Peri-operative complications included 3 strokes, 5 TIA’s, and 2 seizures, and there was no stroke or hemorrhage during the follow-up period. One patient required additional revascularization surgery 8 months after pial synangiosis. Conclusions: Pial synangiosis is a safe, effective, and durable method of cerebral revascularization in adult moyamoya patients. Our data supports the utilization of pial synangiosis as a treatment option for moyamoya disease in adults, particularly when STA-MCA bypass is not technically feasible.

Abstract TMP37: Adult Moyamoya Disease : Clinical Presentation, Treatment Outcome and Prognostic Factor

Background and Purpose: This study was aimed to investigate treatment results and outcome predictors in adult patients with moyamoya disease. Methods: During the period from 2000 to 2011, a clinical database of adult patients with definite moyamoya disease were collected retrospectively from 8 participating centers in Korea during the period from 2000 to 2011. Among total 399 elligible patients, 355 cases were evaluated about clinical and radiological outcomes through medical records. Stroke-free survival rate and prognostic factors for stroke recurrence were measured by Kaplan-Meier and Cox regression methods. Neurologic outcome was assessed according to surgical revascularization and conservative observation. Results: The mean age of symptom onset was 39.4 ( ± 13.8) years. Male to female ratio was 1 to 2.16. Presenting symptoms were ischemia in 197 (55.5%), hemorrhage in 118 (33.2%), and asymptomatic in 40 (11.3%) patients. The median follow-up was 34.3 months (range 0.4 to 284.8). One hundred thirty seven (38.6%) of the 355 patients received observational conservative management. The remaining 218 (61.4%) patients underwent one of direct, indirect or combined revascularization. In the total adult moyamoya patients, 5 year stroke-free survival rate of surgery and observation group was 82.8% vs 73.4%, respectively. In the ischemic moyamoya cases, 5 year stroke-free survival rate of surgery and observation group was 80.9% vs 76.2%, respectively. In the hemorrhagic moyamoya cases, 5 year stroke-free survival rate of surgery and observation group was 83.7% vs 70.1%, respectively. In the asymptomatic cases, 5 year stroke-free survival rate of surgery and observation group was 95.3% vs 83.1%. There was no significant difference between surgical and observation group in Kaplan Meier Survival analysis. Angiographic stage was only a significant factor for stroke recurrence (HR 3.275, 95% CI; 1.251-8.575, P=0.016). Neurologic outcome tended to be better in the surgical group than the observation group (88.5% vs 81.8%, P=0.074) Conclusions: In adult moyamoya patients, the long-term prognosis of surgical treatment may be better than that of conservative observation under real-world setting. Angiographic stage is a predictor of future stroke

Diagnosis and Treatment of Moyamoya Disease

Moyamoya disease is a cerebrovascular disease of unknown etiology, which is characterized by bilateral stenosis or occlusion at terminal portion of internal carotid artery and at proximal portion of anterior cerebral artery and /or middle cerebral artery and abnormal vascular network in the vicinity of the arterial occlusions. It occurs frequently in Asian countries, particularly in Korea and Japan, but is rare in Western countries. To establish the etiology of moyamoya disease, much about the pathology from autopsies, factors involved in its pathogenesis, and its genetics have been studied. It may occur at any age from childhood to adulthood and in general, initial manifestation is cerebral ischemic symptoms in children and intracranial hemorrhage symptoms in adults. Because it progress and cause recurrent stroke, early diagnosis and proper management has been recognized. Cerebral angiography is essential for definitive diagnosis and treatment plan. Magnetic resonance imaging/magnetic resonance angiography is useful for diagnosis and follow-up tools after revascularization. Evaluation of the cerebral hemodynamics by single photon emission computed tomography and positron emission tomography is useful for diagnosis and assessment of the severity of cerebral ischemia in moyamoya patients. Surgical revascularization is effective for moyamoya disease manifesting as ischemic symptoms, to prevent further ischemia and infarction. In hemorrhagic type moyamoya disease, revascularization can be considered. Direct bypass, indirect synangiosis and combined methods are used. Outcomes of revascularization are excellent in preventing transient ischemic attacks in most patients. (Ewha Med J 2013;36(1):9-17)

Complete visual recovery after incipient crao due to ocular hypoperfusion in a patient with moyamoya disease.

The purpose of this study was to report a case of an impending central retinal artery occlusion with hypoperfusion in a moyamoya patient. A young, surgically revascularized moyamoya patient experienced severe unilateral vision loss from 20/25 to hand motions because of impending central retinal artery occlusion. The patient was treated with a combination of intermittent ocular massage, intraocular pressure-lowering medications, and aspirin. A case of a moyamoya patient at Stanford University Medical Center. Visual acuity was restored to baseline by improving the ocular arterial-venous gradient after prompt administration of ocular massage, intraocular pressure-lowering drops, and aspirin. This dramatic result suggests that, if performed in a timely manner, augmentation of ocular perfusion can result in complete restoration of vision in some cases of incipient central retinal artery occlusion.

The Usefulness of the Ivy Sign on Fluid-Attenuated Intensity Recovery Images in Improved Brain Hemodynamic Changes after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Adult Patients with Moyamoya Disease

ObjectiveMR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images.MethodsWe enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery.ResultsIvy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis.ConclusionAfter STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients.

Small dose of propofol combined with dexamethasone for postoperative vomiting in pediatric Moyamoya disease patients: a prospective, observer-blinded, randomized controlled study

BackgroundFor effective postoperative antiemetic management in pediatric moyamoya disease patients receiving fentanyl based postoperative analgesia, a multimodal approach has been recommended. The uncertain efficacy of ondansetron for pediatric neurosurgical patients or the possible antiemetic effect of small dose of propofol motivated us to evaluate the preventive effect of a subhypnotic dose of propofol combined with dexamethasone on postoperative vomiting (POV), especially during immediate postoperative periods.MethodsIn a prospective observer-blind randomized controlled study, we compared dexamethasone 0.15 mg/kg alone (Group D) with dexamethasone combined with propofol of 0.5 mg/kg (Group DP) in 60 pediatric patients, aged 4-17 years, who underwent indirect bypass surgery and received fentanyl-based postoperative analgesia. Occurrence of vomiting and pain score (Wong-Baker facial score) and requirement of rescue analgesic and antiemetic were continually measured (0-2, 2-6, 6-12 and 12-24 postoperative hours). For statistical analysis, in addition to the Fisher's exact test, a generalized linear mixed model (GLMM) and the linear mixed model (LMM) for repeated measures were used for vomiting and pain scores, respectively.ResultsThere was no statistical significance of POV incidence, requirement of rescue analgesic and pain score between the two groups at any measured intervals. The incidence of POV was 53.3% during 24 hours in both groups, and was especially 6.7% and 13.3% (P = 0.671) during 0-2 hr and 16.7% and 23.3% (P = 0.748) during 2-6 hr in group D and group DP, respectively.ConclusionsA small dose of propofol combined with dexamethasone appears ineffective to preventing POV in pediatric moyamoya patients receiving continuous fentanyl infusion.

Analysis of ischemic cerebral lesions using 3.0-T diffusion-weighted imaging and magnetic resonance angiography after revascularization surgery for ischemic disease

BackgroundCerebral revascularization surgery (CRS) is increasingly recognized as an important component in the treatment of complex cerebral vascular disease and tumors. CRS requires that the incidence of perioperative neurological complications should be minimized, because CRS for ischemic disease is often not the goal of treatment, but rather a prophylactic surgery. CRS carries the risk of focal postoperative neurological deficits. Little has been established concerning mechanisms of post-CRS ischemia. We used 3.0-T diffusion-weighted magnetic resonance imaging (DWI) and magnetic resonance angiography (MRA) to analyze the incidence and mechanism of ischemic lesions. MethodsWe studied the anterior circulation territory after 20 CRS procedures involving 33 vascular anastomosis procedures (13 double anastomoses and 7 single anastomoses) in 12 men and 8 women between June 2007 and October 2011. The operations included single or double superficial temporal artery–middle cerebral artery (STA–MCA) anastomosis to treat internal carotid artery/MCA occlusions or severe MCA stenosis. A combined STA–MCA anastomosis and indirect bypass were performed for moyamoya disease. Postoperative DWI and MRA were obtained in all patients between 24 and 96h after surgery to detect thromboembolism, hypoperfusion, or procedural ischemic complications and vasospasms of the donor STA. ResultsFollow-up DWI and MRA were carried out 1.8±0.6 days after CRS (range, 1–4 days). Temporary occlusion time for anastomoses averaged 18.9min (range, 16–32min). Asymptomatic new hyperintensities occurred in the ipsilateral hemisphere of 2 patients on postoperative DWI (10% patients/6.0% anastomoses), and 1 moyamoya patient (5.0% patients/3.0% anastomoses) developed a symptomatic hyperintensity in the ipsilateral occipital lobe in response to the operation. Two abnormal small (<5mm) cortical DWI lesions were caused by sacrifices of a small branch of the recipient MCA. ConclusionThis study is the first postoperative 3.0-T DWI study of CRS and related clinical events. The incidence of symptomatic postoperative DWI abnormalities was restricted to 1 moyamoya patient representing 5.0% of total patients and 3.0% anastomoses. Although some postoperative DWI abnormalities occurred, CRS was found to be safe with a low risk of symptomatic ischemia.

P.R4810K, a polymorphism of RNF213, the susceptibility gene for moyamoya disease, is associated with blood pressure

Moyamoya disease-an idiopathic vascular disorder of intracranial arteries-is often accompanied by hypertension. RNF213 has been identified as a susceptibility gene for moyamoya disease. In the present study, the association of p.R4810K (G>A) with blood pressure (BP) was investigated in a Japanese population. Three independent study populations, the Nyukawa (n=984), Noshiro (n=2,443) and Field (n=881) studies, joined this study. BP, body weight and height were measured. Past and present symptoms and disease and medication histories were assessed by interview. Associations of p.R4810K (rs112735431, ss179362673) of RNF213 with BP were investigated. Two linkage disequilibrium blocks were constructed for moyamoya patients with p.R4810K (n=140) and the general population (n=384) using 39 single nucleotide polymorphisms (SNPs) spanning 390kb around RNF213. A total of 60 carriers (3 for AA genotype and 57 for GA genotype) were found in these samples, and the minor allele frequencies were 1.4% in the Nyukawa and Field studies and 0.2% in the Noshiro study. Regression analyses adjusted for age, sex and body mass index based on an additive model demonstrated significant associations with systolic BP (mmHg/allele): β (standard error) was 8.2 (2.9) in the Nyukawa study (P=4.7×10(-3)), 18.7 (5.4) in the Noshiro study (P=4.6×10(-4)) and 8.9 (2.0) (P=1.0×10(-5)) in the three populations. In contrast, diastolic BP showed significant associations only in the Noshiro study. Linkage disequilibrium blocks contained none of the BP-associated proxy SNPs reported by previous studies. Our study suggests that p.R4810K of RNF213 is associated strongly with systolic BP.

168 Moyamoya Syndrome Associated with Neurofibromatosis Type 1 in Children

Methods Records of all patients seen in a pediatric NF1 clinic were reviewed to identify those with both moyamoya syndrome and NF1. Of these children, a subset underwent a standardized cerebral revascularization surgery, pial synangiosis, as part of a consecutive series of 412 moyamoya patients treated at a single institution between 1988-2010. Results Thirty-five patients had both NF1 and moyamoya syndrome, with 29 undergoing pial synangiosis. Preoperatively, 21/29 patients (72%) were symptomatic prior to surgery, with the majority (19/21 symptomatic patients, 90%) experiencing ischemic symptoms. No patients presented with hemorrhage. On imaging, 18/29 (62%) had radiographic evidence of prior stroke at time of diagnosis of moyamoya. Ten patients had been treated with cranial irradiation and all (100%) presented with bilateral disease at initial diagnosis. Average age at surgery was 8.1 years (range 1.3-15.5). Perioperative complications included 1 stroke and 1 infection. Average follow-up was 75.5 months (range 9.4 – 253.3), with 21/22 patients (95%) demonstrating stable or improved neurologic status (using the modified Rankin scale) and radiographic data indicating a 13-fold reduction in stroke rate. Patients with previous cranial radiation had higher stroke risk.

Moyamoya Disease: Current Concepts

Moyamoya disease is a disease of the cerebral vessels, which is characterized by narrowing of the intracranial vessels as they emerge from the base of the skull, and hypertrophy of fine collateral vessels in response to this vessel narrowing. Moyamoya means the puff of smoke in Japanese, and refers to the appearance of the abnormal fine collateral vessels appearing on cerebral angiography in patients with this condition. The most commonly affected vessels are located in the anterior circulation and include the distal intracranial internal carotid artery, proximal middle cerebral artery, and proximal anterior cerebral artery. Moyamoya disease is progressive and the underlying cause is unknown. The stenotic and occlusive process often begins unilaterally, but true moyamoya disease inevitably progresses to involve the cerebral vessels bilaterally. Patients usually present to medical attention in two distinct age groups. One group of patients presents in childhood and the other group presents in adulthood. There are also two distinct clinical presentations. One group of patients presents with intracranial hemorrhage, most commonly in the basal ganglia or in the ventricles, and sometimes in the subarachnoid space. The other group of patients presents with ischemic symptoms with either transient ischemic attacks or with cerebral infarctions. These infarctions can either be deep perforating artery infarctions, watershed infarctions, or large arterial branch infarctions. Silent infarctions can also be found in some patients at the time of initial presentation, and occasionally patients can present with decreased cognitive function. The condition was first described in Japan, and much of the published literature describing the condition and what is known about it to date, has been published by Japanese investigators. It has subsequently been recognized that moyamoya disease is a cause of stroke and intracerebral hemorrhage in Western as well as in Asian populations. Treatment of the condition usually consists of one of two types of revascularization surgery which are termed indirect and direct revascularization. Indirect revascularization involves placing vascularized tissue fed by the external carotid system on to the surface of the brain to allow collateral networks to form and reroute blood flow around the obstructed vessels at the base of the brain. Direct revascularization most commonly utilizes direct microvasular anastomosis between the superficial temporal and the middle cerebral artery (STA-MCA) in moyamoya patients. This paper reviews the current state of knowledge about the disease and also discusses current management strategies.

Abstract 162: Clinical and Neuroradiological Characteristics of Moyamoya Syndrome: UT Houston Experience

Background: Moyamoya (MM) is a rare progressive arteriopathy characterized by progressive stenosis and occlusion of the internal carotid arteries (ICA) and ultimately the arteries of the circle of Willis. It is called moyamoya disease (MMD) when idiopathic and involving bilateral ICA, and moyamoya syndrome (MMS) when associated with well-recognized risk factors, or when idiopathic but unilateral. Given the paucity of literature on MMS, we analyzed the clinical and radiological characteristics of MM patients presenting to our institute. Methods: We retrospectively identified patients admitted with acute neurological deficits and had ‘moyamoya-like’ physiology from our stroke registry (07/04 to 03/11). We collected demographics, clinical and laboratory data, and prior and subsequent hospital admissions. Two clinically blinded neuroradiologists collected radiological data including vessels involved, type of collateralization, and disease stage and progression. Patients were categorized into MMD or MMS based on risk factors and the side of disease. Results: We identified 36 MM patients (mean age 41.3 years), 13 (36.1%) with MMD and 23 (63.9%) with MMS. Both groups had female preponderance and multiracial involvement; hemiparesis was the leading clinical sign, and most patients had low HDL levels (83%). In MMS group, 4 (17.4%) patients had idiopathic unilateral disease, 4 (17.4%) had atherosclerotic disease, 3 (13%) each had vasculitis and intracranial dissection, 2 (8.7%) each had sickle cell disease and APLA syndrome, and 1 (4.3%) each had Down’s syndrome, Lupus, thyrotoxicosis, hypercoagulable disorder and chronic cocaine use. The MMS patients tended to be older, and higher proportion had ischemic stroke (87%) and neurological worsening after acute event (35%). On the other hand, higher proportion of MMD patients had hemorrhagic stroke (38.5%), multiple (&gt;5) hospital admissions (23%) and EEG abnormality (80%) and were discharged home (62%). In MMS group, 2 (8.7%) patients underwent hemicraniectomy. In MMD group, 12.5% had disease progression radiographically. The clinical and radiological characteristics of these patients are summarized in tables 1 and 2 respectively. Conclusion: We present the single-center experience of clinical and neuroradiological characteristics of patients with MMS.

Abstract 165: Pial Synangiosis in Patients with Moyamoya less than 2 Years of Age

Introduction: Moyamoya patients under two years of age represent a therapeutic challenge because of their frequent neurologic instability and concomitant anesthetic risks. We report our experience with pial synangiosis revascularization in this population. Methods: We reviewed the clinical and radiographic records of all patients with moyamoya syndrome in a consecutive series of patients under 2 years of age, who underwent cerebral revascularization surgery using pial synangiosis at a single institution. Results: During a 12-year period (1994-2005), thirty-four procedures (15 bilateral, 4 unilateral) were performed in 19 patients under two years of age (out of a total of 456 procedures in 240 patients). Eighteen of these patients presented with either stroke or TIA. Average age at first surgery was 1.4 years (range 6 months to 1.9 years). Unanticipated staged operations occurred in three patients, two due to persistent EEG changes during the initial surgery and one due to brain swelling during the procedure requiring ventriculostomy. There were two perioperative strokes; both patients had post-operative seizures but made clinical recoveries. The average follow-up was 7 years (range 1-14). In long term follow-up, 13 patients (68%) were clinically independent for their age, with 8 (42%) having no significant deficit. Late complications included subdural hygroma evacuation (1), additional revascularization procedures years later for frontal lobe ischemia (2), late infarction (1) and asymptomatic ischemic change on routine follow-up MRI studies (1). All patients who had both pre and post-operative angiography demonstrated progression of disease. Conclusions: Despite the challenges inherent to this population, the majority of children with moyamoya under 2 years of age have a good long-term prognosis. Our data support the use of pial synangiosis as a safe, effective and durable method for treatment of moyamoya for most children in this potentially high-risk population.

Abstract 2766: Hemodynamic Changes Following Direct EC-IC Bypass In Moyamoya Disease Patients Measured Using Combined Arterial Spin Labeling And Dynamic Susceptibility Contrast MR Imaging

Background: The goal of direct bypass in Moyamoya patients is to reduce the risk of future strokes, presumably by improving cerebral hemodynamics. Combined ASL and DSC MR perfusion imaging (CAD-perfusion) is a new quantitative methodology to measure perfusion parameters ( 1 ). Methods: We applied this method to 20 newly-diagnosed, symptomatic Moyamoya patients (11 bilateral, 9 unilateral). Imaging was acquired at 3T (GE MR 750, Waukesha, WI) before and approximately 6 months following direct STA-MCA anastomosis. ASL was performed using 3D fast-spin-echo background-suppressed pseudocontinuous ASL with the following parameters (TR/TE/label time/post-label delay 5500/2.5/1500/2000 ms; spatial resolution 3 × 3 × 4 mm; imaging time 4:37). DSC was performed using gradient-echo EPI with the following parameters (TR/TE 1800/40 ms; 1.9 × 1.9 × 5 mm; 0.1 mmol/kg Multihance contrast). Images were co-registered, placed into template space, and resliced to 10 mm axial slice thickness corresponding to the ASPECTS slices using SPM8. CAD-perfusion images (CAD-CBF and CAD-CBV) were created using standard methods ( 1 ). Analysis was by hemisphere (n=20 posterior, n=31 bypassed anterior, and n=9 non-bypassed anterior regions). Hemodynamic measurements were made in mixed cortical ROI’s. The Wilcoxon rank-sum test was used to assess significance at the p&lt;0.05 level. Results: 6 months following bypass, Tmax in the bypassed anterior circulation decreased significantly (from 3.6±1.2 to 3.0±0.9 sec, p=0.019) but did not change in either the non-bypassed anterior circulation or posterior circulation. CAD-CBF did not increase in any of the three regions; in particular, no increase was seen in the anterior bypassed regions (from 34.8±8.5 to 36.8±8.1 ml/100 g/min, p&gt;0.05). This is consistent with prior reports suggesting that baseline CBF does not change following bypass ( 2 ). Interestingly, CAD-CBV was significantly increased in all regions following bypass; this change was largest in the non-bypassed anterior circulation (from 4.5±1.0 to 6.1±2.3%, p=0.035). Conclusion: Hemodynamic changes following bypass are complex and involve both hemispheres. CAD-perfusion MRI allows the ability to follow these parameters in a quantitative way.

Abstract 163: Discovery of Asymptomatic Moyamoya Arteriopathy in Pediatric Syndromic Populations: Radiographic and Clinical Progression

Introduction: Limited data exists to guide management of incidentally discovered pediatric moyamoya. Best exemplified in the setting of unilateral moyamoya, in which the unaffected side is monitored, this phenomenon also occurs in populations undergoing routine surveillance of the cerebral vasculature for other conditions, such as sickle cell disease (SCD) or neurofibromatosis type I (NF1). Here we present our experience with specific syndromic moyamoya populations to better characterize the natural history of radiographic and clinical progression in asymptomatic moyamoya. Methods: Retrospective review of a consecutive series of 418 patients who underwent surgical revascularization for moyamoya disease at a single institution from 1988-2010. Results: Of 418 patients, 83 were asymptomatic at the time of radiographic diagnosis of moyamoya, while also having either unilateral moyamoya or moyamoya in association with either SCD or NF1. Average age at presentation was 9.1 years (range 1-21), with 47 females (60%) and 31 males (40%). Mean follow-up was 5.4 years (SD +/-3.8), with 45 patients (54%) demonstrating radiographic progression and 37 patients (44.6%) becoming symptomatic within this period. The time interval between radiographic progression from the diagnosis of syndromic disease, to evidence of arteriopathy, to signs of slow cortical blood flow, and to stroke was 5.8 years (SD +/-4.7), 0.7 years (SD +/-1.1), and 0.3 years (SD +/-0.5), respectively. SCD patients had the highest incidence of both radiographic (n=15, 75%) and clinical (n=13, 65%) progression, followed by NF1 (n=20, 59% radiographic, n=15, 44% clinical) and unilateral patients (n=10, 34.5% radiographic, n=9, 31%). Transient ischemic attacks were the most frequent symptoms during follow-up (29 patients, 35%), and 10 patients (12%) developed clinical stroke. Overall 49 patients (59%) underwent surgical treatment, and the time between arteriopathy to surgery was 1.1 years (SD +/-1.2). Conclusion: Radiographic progression occurred in the majority of asymptomatic patients and generally heralded subsequent clinical symptoms. SCD or NF patients with asymptomatic moyamoya are more likely to progress and require treatment than unilateral moyamoya patients without a syndromic disease. These data demonstrate that moyamoya is a progressive disorder, even in asymptomatic populations, and supports the rationale of early surgical intervention to minimize morbidity from stroke.

Clinical Features, Prothrombotic Risk Factors, and Long-Term Follow-Up of Eight Pediatric Moyamoya Patients

Background and PurposeThe aim of this study was to elucidate the clinical features, prothrombotic risk factors, and outcome of pediatric Moyamoya patients.MethodsPatients diagnosed with Moyamoya disease at a tertiary center between January 2000 and December 2006 were enrolled in this study. The clinical presentations, underlying diseases, prothrombotic risk factors, family history of thrombosis, radiological findings, treatment, and outcome of the patients were reviewed retrospectively.ResultsEight patients with angiographically proven Moyamoya disease were identified, one of whom had neurofibromatosis type I and one had Down syndrome. The age at diagnosis varied between 19 months and 11 years (73.4±41.8 months, mean±SD). The follow-up period after diagnosis was 52.5±14.8 months. In six patients, the initial clinical presentation was hemiparesis. None of the patients had any identifiable prothrombotic factors. Despite medical and surgical treatment, three patients had recurrences and one died. Only two patients recovered without sequelae.ConclusionsThe value of prothrombotic risk factor evaluation appears to be limited in Moyamoya patients; the outcome for pediatric patients remains dismal.

Prevalence and Epidemiological Features of Moyamoya Disease in Korea

ObjectiveThe objectives of the present study were to investigate the annual detection rate of patients with Moyamoya disease (MMD) and to describe the prevalence and epidemiological features of the Moyamoya patients in Korea.Materials and MethodsThe authors analyzed the epidemiological data of Korean patients taken from the National Health Insurance Corporation in Korea among Moyamoya patients who were treated from 2004 until 2008.ResultsBased on 2004 data, 2,539 MMD patients were treated in Korea and the prevalence rate was 5.2 per 100,000 people. There were 2,987 in 2005, 3,429 in 2006, 4,051 in 2007, and 4,517 cases in 2008, and the prevalence rates per 100.000 people were 6.3, 7.0, 8.6, and 9.1, for those respective years. This represents an annual increase of 15% of new cases during this period. In 2008, 466 people were newly diagnosed with MMD, representing an incidence rate of 1 per 100,000 persons. The gender ratio was 1,547 men (34%) and 2,970 women (66%). Women had a higher incidence rate than men (1.94 times). There were two age peaks: teenagers and those in their forties.ConclusionThe present study shows that the number of Moyamoya patients in Korea is increasing. This increase could partly be explained by a recent increase in newly diagnosed cases, suggesting that a more careful consideration of the disease and better diagnostic techniques should be promoted among clinicians.