Development and validation of machine learning models to predict postoperative infarction in moyamoya disease.

OBJECTIVE: Cerebral infarction is a common complication in patients undergoing revascularization surgery for moyamoya disease (MMD). Although previous statistical evaluations have identified several risk factors for postoperative brain ischemia, the ability to predict its occurrence based on these limited predictors remains inadequately explored. This study aimed to assess the feasibility of machine learning algorithms for predicting cerebral infarction after revascularization surgery in patients with MMD. METHODS: This retrospective study was conducted across two centers and harnessed data from 512 patients with MMD who had undergone revascularization surgery. The patient cohort was partitioned into internal and external datasets. Using perioperative clinical data from the internal cohort, three distinct machine learning algorithms-namely the support vector machine, random forest, and light gradient-boosting machine models-were trained and cross-validated to predict the occurrence of postoperative cerebral infarction. Predictive performance validity was subsequently assessed using an external dataset. Shapley additive explanations (SHAP) analysis was conducted to augment the prediction model's transparency and to quantify the impact of each input variable on shaping both the aggregate and individual patient predictions. RESULTS: In the cohort of 512 patients, 33 (6.4%) experienced postrevascularization cerebral infarction. The cross-validation outcomes revealed that, among the three models, the support vector machine model achieved the largest area under the receiver operating characteristic curve (ROC-AUC) at mean ± SD 0.785 ± 0.052. Notably, during external validation, the light gradient-boosting machine model exhibited the highest accuracy at 0.903 and the largest ROC-AUC at 0.710. The top-performing prediction model utilized five input variables: postoperative serum gamma-glutamyl transpeptidase value, positive posterior cerebral artery (PCA) involvement on preoperative MRA, infarction as the rationale for surgery, presence of an infarction scar on preoperative MRI, and preoperative modified Rankin Scale score. Furthermore, the SHAP analysis identified presence of PCA involvement, infarction as the rationale for surgery, and presence of an infarction scar on preoperative MRI as positive influences on postoperative cerebral infarction. CONCLUSIONS: This study indicates the usefulness of employing machine learning techniques with routine perioperative data to predict the occurrence of cerebral infarction after revascularization procedures in patients with MMD.

The Potential Role of Preoperative Posterior Cerebral Artery Involvement in Predicting Postoperative Transient Neurological Deficits and Ischemic Stroke After Indirect Revascularization in Patients With Moyamoya Disease.

OBJECTIVE: Transient neurological deficits (TNDs) are known to develop after direct bypass for Moyamoya disease and may be risk factors for subsequent stroke. However, the factors involved in the development of TNDs and stroke after indirect revascularization alone, including their association with subsequent stroke, remain unclear. The purpose of this study was to investigate this issue. METHODS: The subjects of the study were 30 patients with Moyamoya disease who underwent a total of 40 indirect revascularization procedures at our institution. Clinical and radiological data were collected retrospectively. To examine factors associated with the development of postoperative TND/stroke/asymptomatic disease, the clinical characteristics of each group were statistically compared. RESULTS: The mean age at surgery was 7 years (range 1-63). TNDs developed after surgery in 9 out of 40 patients (22.5%). Stroke in the acute postoperative period occurred in 3 patients (7.5%), all of whom experienced cerebral infarctions. Demographic data and preoperative clinical information were not different between the groups. However, posterior cerebral artery involvement on preoperative imaging was significantly associated with the development of TNDs and stroke (P = 0.006). Furthermore, postoperative stroke was associated with unfavorable outcomes (P = 0.025). CONCLUSIONS: Posterior cerebral artery involvement is significantly associated with the occurrence of TNDs. In contrast, TNDs after indirect revascularization have little relationship with the subsequent development of stroke. TNDs usually resolve without new strokes, and a better understanding of this particular pathology could help establish an optimal treatment regimen.

Characteristics of donor vessels and cerebral blood flow in the chronic phase after combined revascularization surgery for moyamoya disease.

OBJECTIVE: This study aimed to analyze whether the development of donor vessels after combined revascularization surgery for moyamoya disease (MMD) is related to cerebral blood flow (CBF) changes. METHODS: We retrospectively reviewed the charts of 11 adult (12 hemispheres) and 13 pediatric (19 hemispheres) patients who underwent combined revascularization in our department. The total vessel cross-sectional area (TVA) was the sum of the cross-sectional areas of the superficial temporal, middle meningeal, and deep temporal arteries imaged using time-of-flight magnetic resonance angiography. The ipsilateral relative CBF (RCBF) on the brain surface in the craniotomy area was calculated by single-photon emission computed tomography. ΔTVA and ΔRCBF were defined as the preoperative and postoperative ratios of TVA and RCBF, and their correlations were analyzed in adult and pediatric patients. RESULTS: The TVA and RCBF showed a significant increase after surgery, regardless of the age group. However, there was no significant correlation between ΔTVA and ΔRCBF in either the adult or pediatric groups. While the adult group exhibited significantly higher ΔRCBF values compared to the pediatric group (p < 0.01, r = -0.44), the ΔTVA values were higher in the pediatric group compared to the adult group (p = 0.06). CONCLUSIONS: In the chronic phase after combined revascularization surgery for MMD, the development of measurable TVA of donor vessels does not necessarily correlate with an increase in CBF around the craniotomy area.

Effect of thin-split encephalomyosynangiosis on transient neurological events in revascularization surgery for pediatric patients with moyamoya disease.

OBJECTIVE: Transient neurological events (TNEs) are among the most important events after revascularization surgery in pediatric patients with moyamoya disease (MMD). Although hemodynamic changes and crying are representative factors of TNEs, brain compression by encephalomyosynangiosis (EMS) is another important cause of TNEs. Therefore, the authors assumed that making the EMS as thin as possible reduces the frequency of TNEs. However, thin-split EMS can lead to insufficient development of collateral vessels. This study aimed to evaluate the effects of thin-split EMS in combined revascularization surgery on postoperative outcomes in pediatric patients with MMD. METHODS: The authors retrospectively included 56 consecutive combined revascularization surgeries in the anterior cerebral circulation in pediatric patients with MMD. These surgeries were classified into the former group and thin-split EMS group. The temporal muscle was halved in the former EMS group and split as thinly as possible in the thin-split EMS group. The authors performed between-group comparisons of postoperative stroke events and TNEs during the acute period and the development of collateral flow and stroke events during the chronic period. RESULTS: Former and thin-split EMS procedures were performed in 37 and 19 patients, respectively. TNEs without crying or hemodynamic changes were observed significantly less frequently in the thin-split EMS group than in the former EMS group (0 [0.0%] in the thin-split EMS group vs 9 [24.3%] in the former EMS group, p = 0.021). There were no significant between-group differences in the development of indirect bypass during the chronic period (good: 34 [91.9%] and poor: 3 [8.1%] in the former EMS group vs good: 16 [84.2%] and poor: 3 [15.8%] in the thin-split EMS group; p = 0.397). Additionally, there were no significant between-group differences in the incidence of chronic clinical events, including death or stroke. CONCLUSIONS: Thin-split EMS can reduce TNEs that do not accompany crying or hemodynamic changes. Furthermore, the procedure has sufficient prevention effects against stroke events during the chronic postoperative period in pediatric patients with MMD.

Higher abundance of Campylobacter in the oral microbiome of Japanese patients with moyamoya disease.

Genetic factors alone cannot explain the pathophysiology of moyamoya disease (MMD), and environmental factors such as an immune response are thought to be involved. Oral and gut microbiomes have attracted attention as environmental factors in the pathophysiology of some vascular and autoimmune diseases. However, the relationship between MMD and these microbiomes is yet to be thoroughly investigated. This prospective case-control study aimed to compare the microbiomes of Japanese patients with MMD with those of healthy individuals to identify the specific bacteria involved in MMD. Saliva and fecal samples were collected from 16 patients with MMD who had not undergone revascularization surgery. Fifteen healthy individuals were matched for age, sex, and body mass index. The microbiomes were determined using 16S rRNA sequencing and analyzed using QIIME2. Differentially abundant microbes were identified using LEfSE and ANCOM-BC. In the oral microbiome, the two analytical methods showed that Campylobacter was more abundant in patients with MMD than in healthy individuals. Differences in the gut microbiome were smaller than those in the oral microbiome. In conclusion, the oral microbiome profiles of patients with MMD significantly differ from those of healthy individuals. Campylobacter spp. could be a substantial environmental factor in the pathophysiology of MMD.

The preoperative focal cerebral blood flow status may be associated with slow flow in the bypass graft after combined surgery for moyamoya disease.

Background: The aim of this study was to investigate the association between early postoperative slow flow in bypass grafts and preoperative focal cerebral blood flow (CBF) in patients who underwent combined surgery for moyamoya disease (MMD). Methods: The subjects were 18 patients (22 surgeries) who underwent single photon emission computed tomography (SPECT) before surgery. The CBF value of the middle cerebral artery territory was extracted from the SPECT data, and the value relative to the ipsilateral cerebellar CBF (relative CBF, or RCBF) was calculated. The association between RCBF and early postoperative slow flow in the bypass graft was investigated. In addition, the correlation between the revascularization effect and preoperative RCBF was analyzed. Results: In four of 22 surgeries (18.2%), slow flow in the bypass graft was identified in the early postoperative period. Preoperative RCBF in the slow flow and patent groups was 0.86 ± 0.15 and 0.87 ± 0.15, respectively, with no significant difference (P = 0.72). The signal intensity of four slow-flowed bypasses was improved in all cases on magnetic resonance angiography images captured during the chronic phase (mean of 3.3 months postoperatively). The revascularization scores were 2 ± 0.82 and 2.1 ± 0.68 in the slow flow and patent groups, respectively, and did not differ significantly (P = 0.78). A significant correlation was not observed between preoperative RCBF and the revascularization effect. Conclusion: No significant association was observed between preoperative RCBF and early postoperative slow flow in bypass grafts in patients with MMD undergoing combined surgery. Given the high rate of improved depiction of slow-flowed bypass in the chronic postoperative phase, the conceptual significance of an opportune surgical intervention is to maintain CBF by supporting the patient's own intracranial-extracranial conversion function.

Spatially separate cerebral infarction in the posterior cerebral artery territory after combined revascularization of the middle cerebral artery territory in an adult patient with moyamoya disease and fetal-type posterior communicating artery: illustrative case.

BACKGROUND: Remote cerebral infarction after combined revascularization of the middle cerebral artery (MCA) territory is rare in patients with moyamoya disease (MMD) with a fetal-type posterior communicating artery (PCoA). OBSERVATIONS: A 57-year-old woman developed numbness in her right upper limb and transient motor weakness and was diagnosed with MMD. She also had a headache attack and a scintillating scotoma in the right visual field. Preoperative magnetic resonance angiography (MRA) showed stenosis of the left posterior cerebral artery (PCA). Combined revascularization was performed for the left MCA territory. No new neurological deficits were observed for 2 days after the operation, but right hemianopia, alexia, and agraphia appeared on postoperative day (POD) 4. Magnetic resonance imaging showed a new left occipitoparietal lobe infarction, and MRA showed occlusion of the distal left PCA. After that point, the alexia and agraphia gradually improved, but right hemianopia remained at the time of discharge on POD 18. LESSONS: Cerebral ischemia in the PCA territory may occur after combined revascularization of the MCA territory in patients with fetal-type PCoA. For these cases, a double-barrel bypass or indirect revascularization to induce a slow conversion could be considered on its own as a treatment option.

Angiographic characteristics of improper watershed shift after STA-MCA bypass in a patient with moyamoya disease: illustrative case.

BACKGROUND: In patients with moyamoya disease (MMD) who receive superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, hypoperfusion remote from the anastomosis site rarely occurs. Watershed shift due to direct bypass has been proposed as the mechanism; however, no report has confirmed this phenomenon using angiography. OBSERVATIONS: A 48-year-old man presented with transient weakness in his left arm. Angiography revealed severe bilateral stenosis of the MCAs and moyamoya vessels. The right anterior cerebral artery (ACA) had short stenosis at A2 but ample blood supply to the cortical area of the right ACA and MCA regions. The patient was diagnosed with MMD and received a single STA-MCA bypass. The next day, he had difficulty communicating, and a cerebral infarction away from the anastomosis site was identified. Perfusion examination revealed hyperperfusion around the direct bypass and hypoperfusion away from the anastomosis site. Angiography revealed bypass patency; however, the original anterograde flow of the right ACA decreased significantly at the stenosed point, indicating an improper watershed shift. LESSONS: STA-MCA bypass for patients with MMD can cause an improper watershed shift decreasing cerebral flow. Donor flow should be prepared based on each angiographic characteristic, and the risk of the improper watershed shift should be considered.

Paradoxical symptomatic cerebral blood flow decreases after combined revascularization surgery for patients with pediatric moyamoya disease: illustrative case.

BACKGROUND: Transient neurological deficits (TNDs) develop after cerebral revascularization in patients with moyamoya disease (MMD). The authors report a rare pediatric MMD case with extensive decreased cerebral blood flow (CBF) and prolonged TNDs after combined revascularization. OBSERVATIONS: A 9-year-old boy presented with transient left upper limb weakness, and MMD was diagnosed. A right-sided combined surgery was performed. Two years after the surgery, frequent but transient facial (right-sided) and upper limb weakness appeared. The left internal carotid artery terminal stenosis had progressed. Therefore, a left combined revascularization was performed. The patient's motor aphasia and right upper limb weakness persisted for approximately 10 days after surgery. Magnetic resonance angiography showed that the direct bypass was patent, but extensive decreases in left CBF were observed using single photon emission tomography. With adequate fluid therapy and blood pressure control, the neurological symptoms eventually disappeared, and CBF improved. LESSONS: The environment of cerebral hemodynamics is heterogeneous after cerebral revascularization for MMD, and the exact mechanism of CBF decreases was not identified. TNDs are significantly associated with the onset of stroke during the early postoperative period. Therefore, appropriate treatment is desired after determining complex cerebral hemodynamics using CBF studies.

The usefulness and safety of dexmedetomidine for postoperative sedation in pediatric patients with moyamoya disease.

OBJECTIVE: After revascularization surgery in pediatric patients with moyamoya disease (MMD), resting and avoiding crying is important. However, this inaction is often difficult because of pain or anxiety. Dexmedetomidine (DEX), which has sedative and analgesic properties, may be useful in reducing those uncomfortable conditions; however, its common side effects include bradycardia and hypotension, which have a risk of decreasing the cerebral blood flow. The aim of this study was to investigate the efficacy and safety of using DEX for pediatric patients with MMD in the acute period after revascularization surgery. METHODS: This retrospective study included pediatric patients with MMD who underwent revascularization surgery. Based on whether DEX was used for light sedation during postoperative days (PODs) 0-1 after extubation, the patients were divided into DEX or control groups. For neurological outcomes, the incidence of symptomatic cerebral infarction and transient neurological events (TNEs) during PODs 0-1 and the entire hospitalization were investigated. In addition, the Richmond Agitation-Sedation Scale (RASS) was used to assess the effect of DEX, and bradycardia and hypotension were evaluated as side effects. RESULTS: A total of 84 surgical procedures were included in this study (27 in the DEX group and 57 in the control group). During PODs 0-1, symptomatic infarction was not observed in either group. The incidence of TNEs was almost the same in both groups: 2 (7.4%) of the 27 procedures in the DEX group and 4 (7.0%) of the 57 procedures in the control group (p > 0.99). Moreover, the incidences of symptomatic infarction and TNEs during the entire hospitalization did not differ significantly (symptomatic infarction, p > 0.99; TNEs, p = 0.20). Regarding the DEX effect, the median RASS scores during PODs 0-1 were -1.0 (drowsy) in the DEX group and +1.0 (restless) in the control group, showing a significant difference (p < 0.01). Regarding side effects, bradycardia was observed only in 3 (11.1%) of the 27 procedures in the DEX group (p = 0.03), and hypotension was not observed in any of the cases. CONCLUSIONS: In pediatric patients with MMD who are extubated after revascularization surgery, DEX produced appropriate light sedation and analgesia. The risk for symptomatic infarction is almost the same in cases in which DEX is used and those in which it is not; however, neurosurgeons should be cautious of bradycardia and TNEs as potential side effects.

Comparison of disinfection-residual-bacteria (DRB) after seven different kinds of disinfection: Biofilm formation, membrane fouling and mechanisms.

Membrane fouling is the Achilles' heel of the reverse osmosis (RO) system for high-quality reclaimed water production. Previous studies have found that after the significant selection effect of traditional disinfection, the remaining disinfection-residual bacteria (DRB) may possess more severe biofouling potentials. To provide more constructive advice for the prevention of biofouling, we compared the RO membrane fouling characteristics of DRB after using five commonly used disinfection methods (NaClO, NH2Cl, ClO2, UV, and O3) and two novel disinfection methods (K2FeO4 and the flow-through electrode system (FES)). Compared with the control group (undisinfected, 21.1 % flux drop), the UV-DRB biofilm aggravated biofouling of the RO membrane (23.4 % flux drop), while the FES, K2FeO4, and NH2Cl treatments showed less severe biofouling, with final flux drops of 6.9 %, 8.1 %, and 8.1 %, respectively. Adenosine triphosphate (ATP) was found to be a capable indicator for predicting the biofouling potential of DRB. Systematic analysis showed that the thickness and density of the DRB biofilms were most closely related to the different fouling degree of RO membranes. Moreover, the relative abundance of bacteria with higher extracellular polymeric substance (EPS) secretion levels, such as Pseudomonas and Sphingomonas, was found closely related with the biofouling degree of RO membranes.

Ultrafiltration significantly increased the scaling potential of municipal secondary effluent on reverse osmosis membranes.

Ultrafiltration (UF) was often used as pretreatment in front of reverse osmosis (RO) unit because of its high rejection efficiency of microbes and particles. However, in some cases UF pretreatment might show adverse effects on the RO membrane flux. In this study, the effects of UF pretreatment on secondary effluent water quality and its RO membrane fouling characteristics were explored. There was almost no change of water quality after UF with different molecular weight cut-off (MWCO) membranes (100, 30 and 10 kDa), including total dissolved solid (TDS), alkalinity, conductivity, ion concentrations, etc., while pH increased a little and dissolved organic carbon (DOC) declined by about 1 mg/L. On the contrary, the RO membrane flux of UF permeates presented clear decline in comparison to the secondary effluent. The membrane fouling velocity and steady-state flux of secondary effluent was 0.052 and 0.656, while fouling velocity increased (0.077, 0.071, 0.067) and steady-state flux decreased significantly (0.397, 0.416, 0.448) after 100, 30, 10 kDa UF membrane pretreatment. Scanning electron microscope (SEM) images showed many crystals on the fouled membrane surfaces, which turned out to be CaCO3 by Energy dispersive spectrometer (EDS) analysis and precipitation calculation. After the addition of UF retentates to UF permeates, scaling was prevented and crystals on the RO membrane almost disappeared, which implied the anti-scaling effect of the UF retentates with low concentration. According to anti-scaling performance experiments, the anti-scaling performance of 100 k, 30 k, 10 k retentates was 2.7%, 4.0% and 7.3%, respectively. Excitation emission matrix (EEM) and fourier transform infra-red (FTIR) results showed that these retentates retained by different MWCO membranes were similar and composed of protein-like substances and soluble microbial products. The effect of key minority components in RO system deserved further exploration.

Changes in cerebral blood flow in the postoperative chronic phase after combined cerebral revascularization for moyamoya disease with ischaemic onset.

The purpose of this study was to examine the effects of combined revascularization for ischaemic-onset moyamoya disease (MMD) on cerebral haemodynamics by comparing cerebral blood flow (CBF) during the postoperative chronic phase with preoperative CBF. A retrospective cohort of 24 MMD patients (representing 31 surgeries) who received single photon emission computed tomography (SPECT) before and more than 6 months after surgery was investigated. The CBF value of each vascular territory was extracted from SPECT data, and the value relative to the ipsilateral cerebellar value (relative CBF, or RCBF) was calculated. The correlation between the revascularization effect and the proportional change in RCBF before and after surgery (calculated as post-RCBF/pre-RCBF ("post/pre-RCBF")) was analysed. Furthermore, the relationships between changes in neurological symptoms and post/pre-RCBF were investigated. Preoperative and postoperative mean RCBF values were 0.92 ± 0.15 and 0.96 ± 0.13 (p = 0.619) in the anterior cerebral artery territory, 0.99 ± 0.17 and 1.01 ± 0.17 (p = 0.598) in the middle cerebral artery territory and 1.15 ± 0.22 and 1.14 ± 0.19 (p = 0.062) in the posterior cerebral artery territory, respectively. No significant correlation was found between the revascularization score and post/pre-RCBF. The revascularization score and post/pre-RCBF were not significant predictors of worsening neurological symptoms postoperatively. No significant change in RCBF was observed in any vascular territory in the chronic phase after revascularization. Combined revascularization may assist in the redirection of blood flow from the internal to the external carotid system and contribute to CBF maintenance.

Dural-based Cavernous Malformation at the Temporal Convexity Presenting with Hemorrhage in a Pregnant Woman: Case Report.

Intracranial cavernous malformations (CMs) are benign vascular malformations that arise mostly within the brain parenchyma, but occasionally from the dura mater. Here, we report an extremely rare case of a 29-year-old pregnant woman presenting with hemorrhage in a dural-based CM at the temporal convexity. She presented with headache at 38 weeks of pregnancy. Imaging showed a hemorrhagic mass lesion in the left temporal lobe. Consciousness was clear, with no apparent neurological symptoms or headache. Her baby was delivered by emergency Caesarean section. Magnetic resonance (MR) imaging revealed an enhanced lesion around the hematoma and flow void appearances. Cerebral angiography confirmed the left middle meningeal artery feeding the lesion with apparent contrast medium pooling. Surgical removal of the lesion as a single block was performed. Histological examinations were consistent with CM. The lesion was located outside the brain and attached to the dura mater of the convexity, so the final diagnosis was dural-based CM. The patient was discharged home with her baby without any neurological deficits, and no recurrence has been seen for 2 years. Dural-based CM at the temporal convexity was detected, presenting as headache induced by hemorrhage during pregnancy. The relationship between bleeding of the lesion and pregnancy remains unclear, but female hormones and vascular growth factors during pregnancy can induce morphological changes and angiogenesis in CMs.

Predictors of long-term tumor control after stereotactic radiosurgery for Koos grade 4 vestibular schwannomas.

PURPOSE: To evaluate the predictors of long-term tumor control following stereotactic radiosurgery (SRS) for Koos grade 4 vestibular schwannomas (VSs). METHODS: Overall, 203 sporadic VS patients with compression of the brainstem were treated with SRS. The median tumor volume was 6.7 cm3 (range, 2.0-28.9 cm3) and the median marginal dose was 12 Gy (range, 9-13.5 Gy). RESULTS: The median follow-up period was 152 months (range, 12-277 months). Tumor control (TC) rates at 3, 5, and 10 years were 89%, 85%, and 82%, respectively. Operation-free survival (OFS) rates at 3, 5, and 10 years were 92%, 85%, and 83%, respectively. Middle cerebellar peduncle (MCP) compression on pre-SRS magnetic resonance imaging scans was significant for both TC (p < 0.001, hazard ratio 1.332) and OFS (p < 0.001, hazard ratio 1.306). The 3-, 5-, and 10-year OFS rates were 98%, 94%, and 92% in the low-risk group (MCP compression < 9.8 mm and > 48 years old), and 58%, 25%, and 17% in high-risk group (MCP compression ≥ 9.8 mm and ≤ 48 years old), respectively. Ten patients (4.9%) developed delayed cyst-related complications. Eleven patients (5.4%) developed newly developed or worsened trigeminal neuralgia. No patient developed persistent facial palsy as an adverse radiation effect. A ventricular peritoneal shunt was required in six patients (3%) who developed hydrocephalus after SRS. CONCLUSION: SRS is an acceptable treatment option in selected patients with Koos grade 4 VSs. Risk group classification based on patient age and MCP compression is useful in decision-making of Koos grade 4 VSs.

Long-Term Outcomes of Sporadic Vestibular Schwannomas Treated with Recent Stereotactic Radiosurgery Techniques.

PURPOSE: Vestibular schwannomas (VSs) are benign; thus, understanding long-term tumor control and late adverse radiation effects of stereotactic radiosurgery (SRS) through current radiosurgical techniques is important to inform treatment decisions. Our aim was to clarify long-term tumor control rates and incidence of late adverse radiation effects in patients with VSs followed for 5 years or longer after SRS. METHODS AND MATERIALS: Altogether, 615 patients with VSs (excluding neurofibromatosis type 2 and partially treated tumors) followed for 5 years or longer after SRS using recent radiosurgical techniques were evaluated. All patients were treated at a margin dose of less than 14 Gy. All tumors were classified into 4 categories: type A (intracanalicular tumor, 87 patients [14%]), type B (cerebellopontine angle [CPA] tumor, 325 patients [53%]), type C (CPA tumor compressing the brain stem, 138 patients [22%]), and type D (CPA tumor compressing the brain stem with a deviation of the fourth ventricle, 65 patients [11%]). Median tumor volume was 2.0 cm3 and median marginal dose was 12 Gy. RESULTS: Median follow-up period was 158 months. Actuarial 5-, 10-, and 15-year or longer local control (LC) rates were 93%, 91%, and 89%, respectively. Tumor type (P < .001, hazard ratio 2.389) and number of prior surgeries (P = .007, hazard ratio 1.698) were significant for LC. Depending on the tumor type, the actuarial 10-year LC rates were 100%, 93%, 88%, and 70% in type A, B, C, and D tumors, respectively. No patient developed persistent facial palsy. Twenty patients (3.3%) developed delayed cysts. One patient developed malignant transformation (0.2%). CONCLUSIONS: SRS is a safe and effective treatment for VSs in the long term, excluding VSs compressing the brain stem with a deviation of the fourth ventricle. Delayed cysts such as cyst formation, enlarged preexisting cysts or extratumoral cysts, and malignant transformation should be considered possible causes of long-term treatment failures.

[A Case of Unilateral Multiple Cerebral Edema 4 Weeks after Coil Embolization].

Coil embolization for cerebral aneurysms can lead to various complications, such as aneurysm rupture and cerebral embolism. In recent years, foreign substance embolisms-caused by peeling off of coating materials from therapeutic devices-have been described. We report here a case of unilateral multiple cerebral edema four weeks after coil embolization. A 44-year-old woman presented with a subarachnoid hemorrhage from a right internal carotid-posterior communicating artery aneurysm, for which coil embolization was performed. Four weeks after the embolization, she developed numbness in the left side of her mouth and in her left upper extremity. Magnetic resonance images showed multiple edematous lesions in the right cerebral hemisphere. Subsequent treatment with steroids improved her symptoms and edematous cerebral lesions. Although definitive diagnosis by biopsy was not performed, her clinical course and imaging findings resembled a foreign substance embolism by hydrophilic coating. It is important to note that delayed cerebral edema due to foreign substance embolisms might occur after endovascular treatments.

Subarachnoid Hemorrhage After Ischemic Stroke Associated with Systemic Lupus Erythematosus and Antiphospholipid Syndrome.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease associated with increased risk of stroke. Antiphospholipid syndrome is another autoimmune disease that frequently overlaps with SLE. We report the case of a patient presenting with subarachnoid hemorrhage after ischemic stroke associated with SLE and antiphospholipid syndrome. CASE DESCRIPTION: A 22-year-old man presented with cerebral infarction of the right corona radiata. He had no contributory past or family histories. On imaging at this time, a 4-mm fusiform aneurysm of the right anterior cerebral artery was incidentally detected. Several examinations were performed, but no abnormalities or abnormal lesions were seen on echography or whole-body computed tomography. Blood tests yielded positive results for antinuclear antibody, lupus anticoagulant, and anti-beta-2 glycoprotein І antibody. He presented 70 days later with subarachnoid hemorrhage. Cerebral angiography showed the same fusiform aneurysm without any change in shape and no new aneurysms. The balloon occlusion test was performed without any neurologic symptoms, so the right anterior cerebral artery was trapped using coils. After 6 months, he presented with new optic hyperesthesia and facial butterfly-shaped erythema and fulfilled the criteria for SLE. At 2 years after initial presentation, he showed no recurrence of either aneurysm or ischemic stroke. CONCLUSIONS: The patient's first ischemic stroke was induced by antiphospholipid syndrome and underlying SLE. Fusiform aneurysm may have resulted from focal vasculitis, with activation of SLE leading to aneurysm rupture.

Repeated Intracranial Hemorrhage After Delivery Induced by Coagulopathy Associated with Multiple Venous Malformations.

BACKGROUND: Venous malformations are classified as slow-flow vascular malformations. Coagulation abnormalities are known to be frequent among patients with venous malformations. We report a case of repeated intracranial hemorrhage after delivery, induced by coagulopathy associated with multiple venous malformations. CASE DESCRIPTION: A 28-year-old woman presented with left chronic subdural hematoma 1 month after successfully giving birth. She had a history of multiple venous malformations around the pubic region and hips. The hematoma was evacuated by burr hole surgery. Three hours later, her level of consciousness rapidly deteriorated and computed tomography showed acute epidural hematoma. The hematoma was removed immediately by craniotomy under general anesthesia. No bleeding points were apparent in the operative field. Continuous bleeding around the dura mater and subdural space were encountered, and hemostasis was not achieved by electrocoagulation. After using fresh frozen plasma, hemostasis was achieved. Level of consciousness and neurologic symptoms improved postoperatively. Magnetic resonance imaging revealed multiple venous malformations in bilateral lower extremities and the pelvis. Disseminated intravascular coagulopathy was diagnosed, and thrombomodulin and blood coagulation factor XIII were administered. She was discharged home without any neurologic deficits. CONCLUSIONS: The delivery activated localized intravascular coagulopathy in the venous malformations and induced chronic subdural hematoma. Surgical interventions then resulted in progression of the coagulopathy to disseminated intravascular coagulopathy, inducing acute epidural hematoma.

Long-Term Outcomes for Pediatric Patients with Brain Arteriovenous Malformations Treated with Gamma Knife Radiosurgery, Part 2: The Incidence of Cyst Formation, Encapsulated Hematoma, and Radiation-Induced Tumor.

OBJECTIVE: Long-term data about the incidence of late adverse radiation effects (AREs) in pediatric brain arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS) are lacking. This study addresses the incidence of late AREs, including cyst formation (CF), chronic encapsulated hematoma (CEH), and radiation-induced tumor, in pediatric patients with AVM treated with GKRS. METHODS: This is a single-institutional study involving pediatric patients with AVM who underwent GKRS between 1991 and 2014. Among 201 pediatric patients with AVM (age ≤15 years), 189 who had at least 12 months of follow-up were assessed in this study. The median treatment volume was 2.2 cm3, and the median marginal dose was 20 Gy. RESULTS: The mean follow-up period was 136 months. During the follow-up period, symptomatic radiation-induced perilesional edema was found in 5 patients (3%), CFs in 7 patients (4%), CEHs in 7 patients (4%), and radiation-induced tumors in 2 patients (1%). The cumulative incidences of late AREs including CF, CEH, and radiation-induced tumor were 1.2% at 5 years, 5.2% at 8 years, 6.1% at 10 years, 7.2% at 15 years, and 17.0% at 20 years. In the multivariate analysis, treatment volume alone was a significant factor for late AREs (P < 0.001; hazard ratio, 1.111). CONCLUSIONS: GKRS is a reasonable treatment option for pediatric AVMs to prevent future intracranial hemorrhages, particularly in the eloquent regions. However, considerable attention should be paid to late AREs such as CFs, CEHs, and radiation-induced tumors because of longer life expectancy in pediatric patients.