Resolution of white matter hyperintensity after surgical revascularization in moyamoya disease - A report of three cases.

Background: Moyamoya disease often presents white matter hyperintensity (WMH) lesions on fluid-attenuated inversion recovery (FLAIR) images, which is generally accepted as irreversible. We, herein, describe three cases of moyamoya disease with WMH lesions that regressed or disappeared after surgical revascularization. Case Description: This report included two pediatric and one young adult case that developed transient ischemic attacks or ischemic stroke due to bilateral Moyamoya disease. Before surgery, five of their six hemispheres had WMH lesions in the subcortical and/or periventricular white matter on FLAIR images. The lesions included morphologically two different patterns: "Striated" and "patchy" morphology. In all of them, combined bypass surgery was successfully performed on both sides, and no cerebrovascular events occurred during follow-up periods. On follow-up magnetic resonance examinations, the "striated" WMH lesions completely disappeared within six months, while the "patchy" WMH lesions slowly regressed over 12 months. Conclusion: Based on radiological findings and the postoperative course of the WMH lesions, the "striated" WMH lesions may represent the inflammation or edema along the neuronal axons due to cerebral ischemia, while the "patchy" WMH lesions may represent vasogenic edema in the white matter through the blood-brain barrier breakdown. Earlier surgical revascularization may resolve these WMH lesions in Moyamoya disease.

Evolutionary origin of alpha rhythms in vertebrates.

The purpose of this review extends beyond the traditional triune brain model, aiming to elucidate the evolutionary aspects of alpha rhythms in vertebrates. The forebrain, comprising the telencephalon (pallium) and diencephalon (thalamus, hypothalamus), is a common feature in the brains of all vertebrates. In mammals, evolution has prioritized the development of the forebrain, especially the neocortex, over the midbrain (mesencephalon) optic tectum, which serves as the prototype for the visual brain. This evolution enables mammals to process visual information in the retina-thalamus (lateral geniculate nucleus)-occipital cortex pathway. The origin of posterior-dominant alpha rhythms observed in mammals in quiet and dark environments is not solely attributed to cholinergic pontine nuclei cells functioning as a 10 Hz pacemaker in the brainstem. It also involves the ability of the neocortex's cortical layers to generate traveling waves of alpha rhythms with waxing and waning characteristics. The utilization of alpha rhythms might have facilitated the shift of attention from external visual inputs to internal cognitive processes as an adaptation to thrive in dark environments. The evolution of alpha rhythms might trace back to the dinosaur era, suggesting that enhanced cortical connectivity linked to alpha bands could have facilitated the development of nocturnal awakening in the ancestors of mammals. In fishes, reptiles, and birds, the pallium lacks a cortical layer. However, there is a lack of research clearly observing dominant alpha rhythms in the pallium or organized nuclear structures in fishes, reptiles, or birds. Through convergent evolution, the pallium of birds, which exhibits cortex-like fiber architecture, has not only acquired advanced cognitive and motor abilities but also the capability to generate low-frequency oscillations (4-25 Hz) resembling alpha rhythms. This suggests that the origins of alpha rhythms might lie in the pallium of a common ancestor of birds and mammals.

Intracerebral transplantation of MRI-trackable autologous bone marrow stromal cells for patients with subacute ischemic stroke.

BACKGROUND: Ischemic stroke is one of the leading causes of death and neurological disability worldwide, and stem cell therapy is highly expected to reverse the sequelae. This phase 1/2, first-in-human study evaluated the safety, feasibility, and monitoring of an intracerebral-transplanted magnetic resonance imaging (MRI)-trackable autologous bone marrow stromal cell (HUNS001-01) for patients with subacute ischemic stroke. METHODS: The study included adults with severe disability due to ischemic stroke. HUNS001-01 cultured with human platelet lysates and labeled with superparamagnetic iron oxide was stereotactically transplanted into the peri-infarct area 47-64 days after ischemic stroke onset (dose: 2 or 5 × 107 cells). Neurological and radiographic evaluations were performed throughout 1 year after cell transplantation. The trial was registered at UMIN Clinical Trial Registry (number UMIN000026130). FINDINGS: All seven patients who met the inclusion criteria successfully achieved cell expansion, underwent intracerebral transplantation, and completed 1 year of follow-up. No product-related adverse events were observed. The median National Institutes of Health Stroke Scale and modified Rankin scale scores before transplantation were 13 and 4, which showed improvements of 1-8 and 0-2, respectively. Cell tracking proved that the engrafted cells migrated toward the infarction border area 1-6 months after transplantation, and the quantitative susceptibility mapping revealed that cell signals at the migrated area constantly increased throughout the follow-up period up to 34% of that of the initial transplanted site. CONCLUSIONS: Intracerebral transplantation of HUNS001-01 was safe and well tolerated. Cell tracking shed light on the therapeutic mechanisms of intracerebral transplantation. FUNDING: This work was supported by the Japan Agency for Medical Research and Development (AMED; JP17bk0104045 and JP20bk0104011).

Detection of Hyperdense Arterial Sign in Acute Ischemic Stroke with Dual-Energy Computed Tomography: Optimal Combination with X-ray Energy and Slice Thickness.

BACKGROUND: The hyperdense artery sign (HAS) in acute ischemic stroke (AIS) is considered an important marker of a thrombus on computed tomography (CT). An advantage of scanning with dual-energy CT (DECT) is its ability to reconstruct CT images with various energies using the virtual monochromatic imaging (VMI) technique. The aim of this study was to investigate the optimal combination of X-ray energy and slice thickness to detect HASs on DECT. METHODS: A total of 32 patients with confirmed occlusion of the horizontal (M1) portion of the middle cerebral artery were included in this study. Modified contrast-to-noise ratio (modified CNR) analysis was used as a method for evaluating HASs in AIS. A region of interest (ROI) was set as an HAS, the M1 portion, and an approximately 2 cm diameter ROI was set as the background including the HAS and measured. CT images with X-ray energies from 40 to 190 keV, with increments of 10 keV, were reconstructed based on VMI with 1, 2, and 3 mm slice thicknesses. RESULTS: The top five combinations of X-ray energy and slice thickness in descending order of the mean HAS-modified CNR were as follows: Rank 1, 60 keV-1 mm; Rank 2, 70 keV-1 mm; Rank 3, 60 keV-2 mm; Rank 4, 80 keV-2 mm; Rank 5, 60 keV-3 mm. CONCLUSIONS: Our study showed that the optimal combination to detect an HAS was 60 keV and a 1 mm slice thickness on DECT.

Diagnosis of a Dural Arteriovenous Fistula Involving the Superior Sagittal Sinus: The MMA Sign on Routine 3D-TOF MR Angiography.

BACKGROUND AND PURPOSE: The main feeding artery of a dural arteriovenous fistula (DAVF) involving the superior sagittal sinus (SSS) is the middle meningeal artery (MMA). MMA extends continuously from the proximal part to SSS in DAVF involving SSS. It is possible to diagnose DAVF involving SSS by evaluating the proximal part of MMA on routine three-dimensional time-of-flight MR angiography (MRA). We termed the finding in an anteroposterior maximum intensity projection (MIP) image of routine MRA in which MMA was continuously visualized at the top of the imaging slab (the upper corpus callosum level) without tapering as the MMA sign. The purpose of the present study was to examine the frequency of the MMA sign on routine MRA in patients with DAVF involving SSS and control patients. MATERIALS AND METHODS: Subjects comprised 18 patients with DAVF involving SSS confirmed by angiography and 871 control subjects who underwent routine MRA. The presence of the MMA sign was retrospectively evaluated using an anteroposterior MIP image of routine MRA in patients with DAVF involving SSS and control patients. RESULTS: The MMA sign was observed in 17 of the 18 (94%) patients with DAVF involving SSS. In one patient with DAVF involving the posterior part of SSS without the MMA sign, the main feeding artery was the occipital artery, not MMA. The MMA sign was observed in 13 of the 871 (1.5%) control patients. CONCLUSION: The MMA sign on routine MRA is useful, suggesting DAVF involving SSS.

Hemorrhage from metastatic brain epithelioid hemangioendothelioma: A case report.

In this report, we describe a very rare case of metastatic epithelioid hemangio-endothelioma (EHE) originating from other organs such as the lung and requiring craniotomy due to subsequent hemorrhage. A 50-year-old man was diagnosed with EHE in the bilateral lungs, the mediastinum, and the right adrenal gland 8 years earlier. One year earlier, he had developed spinal metastasis. Six months earlier, a screening brain MRI had revealed multiple brain metastases of tumor. He developed subcortical hemorrhage from the tumor in the right parietal lobe and successfully underwent removal of hematoma and tumor. Histopathological examinations revealed EHE. Metastatic EHE is very rare but may be at high risk of intracranial hemorrhage. It is quite important to consider the possibility of brain metastasis and subsequent bleeding when treating patients with EHE.

Clinical Significance of Carotid Endarterectomy and Carotid Artery Stenting in Older Patients Over 80.

As the average life expectancy increases, neurosurgeons are likely to encounter patients aged 80 years and above with carotid stenosis; however, whether old age affects clinical post-treatment outcomes of carotid endarterectomy (CEA) or carotid artery stenting (CAS) remains inconclusive. Thus, this study aimed to evaluate the outcomes following CEA or CAS in patients aged 80 years and above. This study included older over 80 years (n = 34) and younger patients (<80 years; n = 222) who underwent CEA or CAS between 2012 and 2022. All of them were followed up for a mean of 55 months. All-cause mortality, the incidence of vascular events, ability to perform daily activities, and nursing home admission rates were assessed. During follow-up periods, 34 patients (13.3%) died due to coronary artery disease, malignancy, and pneumonia, and the incidence was significantly higher in the elderly group than in the younger group (P = 0.03; HR, 3.01; 95% CI, 1.53-5.56). The incidence of vascular events did not differ between the older group (29.5%) and the younger group (26.9%, P = 0.58); however, the incidence was significantly higher in patients with high-intensity plaques than in those without that (P = 0.008; HR, 2.83, 95%CI, 1.27-4.87). The decline in the ability to perform daily activities and increased nursing home admission rates were high in elderly patients (P < 0.01). Although the mortality rate was higher in the elderly group, subsequent vascular events were comparable to that in the younger group. The results suggest that CEA and CAS are safe and useful treatments for carotid stenosis in older patients, especially to prevent ipsilateral ischemic stroke.

Posterior cerebral artery involvement in unilateral moyamoya disease is exclusively ipsilateral and influenced by RNF213 mutation gene dose: The SUPRA Japan study: PCA involvement in unilateral moyamoya.

OBJECTIVES: The characteristics and clinical implications of posterior cerebral artery (PCA) involvement in unilateral moyamoya disease (U-MMD), such as laterality, frequency of the RNF213 p.R4810K mutation, and clinical outcomes, have not been well studied. POPULATION AND METHODS: We analyzed a cohort of 93 patients with U-MMD who participated in the SUPRA Japan study. Clinical characteristics and radiological examinations were collected from medical records. The presence of the p.R4810K mutation was determined using a TaqMan assay. The clinical outcome was assessed using the modified Rankin Scale (mRS). Univariate and multivariate logistic regression analyses were performed to assess the associations. RESULTS: Among the patients with U-MMD, PCA involvement was observed in 60.0 % (3/5) of patients with homozygous mutation, 11.3 % (7/62) of those with heterozygous mutation, and 3.8 % (1/26) of those with wild type, showing a significant linear trend (p < 0.001 for trend). PCA involvement was observed exclusively on the same side as the affected anterior circulation. Dyslipidemia and cerebral infarction at initial onset were independently associated with mRS ≥1. Hypertension was associated with mRS ≥1 and it was also linked to infarction at initial onset, suggesting a potential confounding effect. Although PCA involvement showed a trend for higher mRS, it was not statistically significant. CONCLUSIONS: Our findings indicate a gene dose effect of the p.R4810K mutation on PCA involvement, with the homozygous state showing the most significant effect. Both genetic and modifiable factors such as dyslipidemia may influence the progression of U-MMD.

Pituitary apoplexy in endocrinologically silent adenoma during somatostatin analog administration for pancreatic neuroendocrine tumor: A case report.

A dopamine agonist administered for prolactinoma treatment and pituitary stimulation tests are reported as risk factors for pituitary apoplexy. We report a case of an 82-year-old patient who suffered from pituitary apoplexy in an endocrinologically silent adenoma during lanreotide administration. The patient was diagnosed with a pancreatic neuroendocrine tumor with lymph node metastasis and treated with lanreotide for two years. An endoscopic endonasal transsphenoidal approach was used for tumor and hematoma removal. The specimen showed growth hormone and prolactin positivity and was diagnosed as pit1-lineage plurihormonal adenoma. The tumor also showed positivity for somatostatin receptor 2. Thus, lanreotide treatment is a risk factor for pituitary apoplexy even in silent adenoma.

Intracerebral Hematoma in Patients With Impella Ventricular Assist Device Placement for Cardiogenic Shock: Report of Three Cases.

Despite the clear benefits of Impella in patients with cardiogenic shock, bleeding is a possible complication. Herein, we report three cases of intracerebral hemorrhage in patients with Impella implantation for cardiogenic shock, which were treated with hematoma evacuation. We present the clinical features, diagnosis, and management (hematoma evacuation) of patients with the Impella device (Abiomed, Danvers, Massachusetts) who developed intracerebral hemorrhage. Case one was a 56-year-old man who presented with chest pain and loss of consciousness, was diagnosed with acute myocardial infarction, and underwent urgent percutaneous coronary intervention and Impella placement. After eight days, the patient developed anisocoria. Computed tomography revealed a left intracerebral hemorrhage. An emergency hematoma evacuation was successfully performed (intraoperative blood loss: 2600 mL). Case two was a 54-year-old male who presented with persistent chest pain and loss of consciousness, was diagnosed with acute myocardial infarction, and underwent an emergency percutaneous coronary intervention with Impella implantation and venoarterial extracorporeal membrane oxygenation. The patient developed intracerebral hemorrhage after 26 days. Hematoma evacuation was successfully performed (intraoperative blood loss: 380 mL). Case three was a 52-year-old male who presented with dyspnea and hypotension, was diagnosed with dilated cardiomyopathy, and underwent Impella implantation and venoarterial extracorporeal membrane oxygenation, followed by which the patient developed subcortical hematoma. An emergency hematoma evacuation was performed (intraoperative blood loss: 3205 mL). The patient died 14 days after admission. Intracerebral hemorrhage is a potential cause of morbidity associated with Impella placement. Although hematoma evacuation is optimal, the bleeding tends to increase.

Neural Mechanisms of Neuro-Rehabilitation Using Transcranial Direct Current Stimulation (tDCS) over the Front-Polar Area.

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation (NIBS) technique that applies a weak current to the scalp to modulate neuronal excitability by stimulating the cerebral cortex. The technique can produce either somatic depolarization (anodal stimulation) or somatic hyperpolarization (cathodal stimulation), based on the polarity of the current used by noninvasively stimulating the cerebral cortex with a weak current from the scalp, making it a NIBS technique that can modulate neuronal excitability. Thus, tDCS has emerged as a hopeful clinical neuro-rehabilitation treatment strategy. This method has a broad range of potential uses in rehabilitation medicine for neurodegenerative diseases, including Parkinson's disease (PD). The present paper reviews the efficacy of tDCS over the front-polar area (FPA) in healthy subjects, as well as patients with PD, where tDCS is mainly applied to the primary motor cortex (M1 area). Multiple evidence lines indicate that the FPA plays a part in motor learning. Furthermore, recent studies have reported that tDCS applied over the FPA can improve motor functions in both healthy adults and PD patients. We argue that the application of tDCS to the FPA promotes motor skill learning through its effects on the M1 area and midbrain dopamine neurons. Additionally, we will review other unique outcomes of tDCS over the FPA, such as effects on persistence and motivation, and discuss their underlying neural mechanisms. These findings support the claim that the FPA could emerge as a new key brain region for tDCS in neuro-rehabilitation.

Current status and future outlook of ultrasound treatment for prostate cancer.

Radical prostatectomy and radiation therapy are the standard treatment options for localized prostate cancer (PC). However, radical prostatectomy may cause the deterioration of urinary and sexual function, and radiation-induced hemorrhagic cystitis and severe rectal bleeding are risk factors for fatal conditions in patients after radiation therapy. With the recent development of magnetic resonance imaging (MRI) for the localization of clinically significant PC (csPC) and treatment modalities, "focal therapy", which cures csPC while preserving anatomical structures related to urinary and sexual functions, has become a minimally invasive treatment for localized PC. Based on the clinical results of transrectal high-intensity focused ultrasound (HIFU) for localized PC in the whole gland and focal therapy, HIFU is considered an attractive treatment option for focal therapy. Recently, the short-term clinical results of transurethral high-intensity directional ultrasound (HIDU) have been reported. With the resolution of some issues, HIDU may be commonly used for PC treatment similar to HIFU. Because HIFU and HIDU have limitations regarding the treatment of patients with large prostate calcifications and large prostate volumes, the proper use of these modalities will enable the treatment of any target area in the prostate. To establish a standard treatment strategy for localized PC, pair-matched and historically controlled studies are required to verify the oncological and functional outcomes of ultrasound treatment for patients with localized PC.

Effects of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis on the cerebrospinal fluid gas tensions and pH in hemodynamically compromised patients.

PURPOSE: This study was aimed to directly measure cerebrospinal fluid (CSF) gas tensions and pH before and after STA-MCA anastomosis for occlusive carotid artery diseases to investigate its direct effects on the ischemic brain. METHODS: This study included 9 patients who underwent STA-MCA anastomosis on the basis of CBF studies. About 1 mL of CSF was collected before and after bypass procedures, and CSF pH, CSF PO2, and CSF PCO2 were measured with a blood gas analyzer. As the controls, the CSF was collected from 6 patients during surgery for unruptured cerebral aneurysm. CSF PO2 and CSF PCO2 were expressed as the ratio to PaO2 and PaCO2, respectively. RESULTS: Before bypass procedure, CSF PO2/PaO2 was 0.88 ± 0.16, being lower than the controls (1.10 ± 0.09; P = 0.005). CSF PCO2/PaCO2 was 0.93 ± 0.13, being higher than the controls (0.84 ± 0.06; P = 0.039). Ipsilateral-to-contralateral CBF ratio had a positive correlation with CSF PO2/PaO2 (P = 0.0028) but a negative correlation with the CSF PCO2/PaCO2 (P = 0.0045). STA-MCA anastomosis increased CSF pH from 7.402 ± 0.133 to 7.504 ± 0.126 (P = 0.0011) and CSF PO2/PaO2 from 0.88 ± 0.16 to 1.05 ± 0.26 (P = 0.018) but decreased CSF PCO2/PaCO2 from 0.93 ± 0.13 to 0.70 ± 0.17 (P = 0.0006). CONCLUSION: The severity of cerebral ischemia before surgery is intensely reflected in the gas tensions and pH of the CSF. STA-MCA anastomosis carries dramatic effects on CSF gas tensions and pH in hemodynamically compromised patients. CSF would be a valuable surrogate biomarker to monitor the severity of cerebral ischemia.

Walk-In Hospital Admission of Patients with Subarachnoid Hemorrhage: Clinical Presentation and Outcome.

OBJECTIVE: Neurosurgeons occasionally encounter cases of subarachnoid hemorrhage (SAH) in admitted walk-in patients, termed "walk-in SAH." However, their clinical characteristics have not been fully understood. We thus, aimed to investigate several characteristics of patients with walk-in SAH and compare them with those of patients with good grade SAH who arrived at the hospital by ambulance. METHODS: Between January 2011 and January 2018, consecutive patients with World Federation of Neurosurgical Society (WFNS) grade I and II aneurysmal SAH were enrolled. They were dichotomized into walk-in and ambulance groups, and their demographic and disease-related characteristics were compared. Furthermore, predictors associated with unfavorable outcomes were investigated in patients with walk-in SAH. RESULTS: Of 171 patients with World Federation of Neurosurgical Society grade I and II SAH, 68 (39.8%) were categorized as walk-in SAH. The mean time for diagnosis in patients with walk-in SAH was significantly longer than that in patients who arrived by ambulance (P < 0.01). Multivariate analysis demonstrated that a lower rate of hypertension, high grades on the Barrow Neurological Institute scale, and Early Brain Edema Score were significantly associated with walk-in SAH (odds ratio [OR] 0.44, 95% confidence interval [CI] 0.21-0.91, P = 0.03; OR 0.32, 95% CI 0.13-0.76, P = 0.007; OR 0.11, 95% CI 0.02-0.51, P < 0.0001, respectively). Additionally, severe angiographic vasospasm was a significant predictor of unfavorable outcomes in walk-in SAH (OR 37.7, 95% CI 1.10-1290.90, P = 0.04). CONCLUSIONS: Patients with walk-in SAH exhibit radiological characteristics associated with a more favorable outcome among patients with good grade SAH. Therefore, these patients may have a positive prognosis.

Adult Moyamoya Disease and Syndrome: Current Perspectives and Future Directions: A Scientific Statement From the American Heart Association/American Stroke Association.

Adult moyamoya disease and syndrome are rare disorders with significant morbidity and mortality. A writing group of experts was selected to conduct a literature search, summarize the current knowledge on the topic, and provide a road map for future investigation. The document presents an update in the definitions of moyamoya disease and syndrome, modern methods for diagnosis, and updated information on pathophysiology, epidemiology, and both medical and surgical treatment. Despite recent advancements, there are still many unresolved questions about moyamoya disease and syndrome, including lack of unified diagnostic criteria, reliable biomarkers, better understanding of the underlying pathophysiology, and stronger evidence for treatment guidelines. To advance progress in this area, it is crucial to acknowledge the limitations and weaknesses of current studies and explore new approaches, which are outlined in this scientific statement for future research strategies.

Academic Activities of Female Neurosurgeons in All Branch Meetings of the Japan Neurosurgical Society.

This study aims to evaluate the academic activities of female neurosurgeons at all branch meetings of the Japan Neurosurgical Society and identify related issues they encountered. The programs of all seven branch meetings of the Japan Neurosurgical Society (Hokkaido, Tohoku, Kanto, Chubu, Kinki, Chugoku/Shikoku, and Kyushu) were used to determine the number of presentations and chairpersons by sex. The covered period was from January 2008 to December 2020, which was available for viewing during the survey. Of note, only the Kinki branch used data from January 2008 to December 2019. The Neurologia Medico-chirurgica (NMC), the journal of the Japan Neurosurgical Society, was also reviewed to identify publication achievements during the same period. In all seven branches, the percentage of presentations given by female physicians increased from 7.9% in 2008 to 9.6% in 2020 (p < 0.05).Conversely, the percentage of female chairpersons in all branch meetings did not change over time and it was significantly lower (1.1%) than that of female presenters (7.9%) for all branch meetings combined in over 13 years (p < 0.01). In the NMC, the number of articles with female physicians as first authors did not increase or decrease over the years. We conclude that efforts to smoothly promote female neurosurgeons as chairpersons and increase the number of female first authors are necessary to facilitate their academic activities.

Beat-wise segmentation of electrocardiogram using adaptive windowing and deep neural network.

Timely detection of anomalies and automatic interpretation of an electrocardiogram (ECG) play a crucial role in many healthcare applications, such as patient monitoring and post treatments. Beat-wise segmentation is one of the essential steps in ensuring the confidence and fidelity of many automatic ECG classification methods. In this sense, we present a reliable ECG beat segmentation technique using a CNN model with an adaptive windowing algorithm. The proposed adaptive windowing algorithm can recognise cardiac cycle events and perform segmentation, including regular and irregular beats from an ECG signal with satisfactorily accurate boundaries.The proposed algorithm was evaluated quantitatively and qualitatively based on the annotations provided with the datasets and beat-wise manual inspection. The algorithm performed satisfactorily well for the MIT-BIH dataset with a 99.08% accuracy and a 99.08% of F1-score in detecting heartbeats along with a 99.25% of accuracy in determining correct boundaries. The proposed method successfully detected heartbeats from the European S-T database with a 98.3% accuracy and 97.4% precision. The algorithm showed 99.4% of accuracy and precision for Fantasia database. In summary, the algorithm's overall performance on these three datasets suggests a high possibility of applying this algorithm in various applications in ECG analysis, including clinical applications with greater confidence.

Coil embolization for post-bypass aneurysm of middle meningeal artery for moyamoya disease - preservation of transdural anastomosis.

Background: Middle meningeal artery (MMA) pseudoaneurysm following revascularization surgery for moyamoya disease (MMD) is rare. Case Description: Here, a 29-year-old man presented with an MMA pseudoaneurysm after he underwent revascularization surgery (superficial temporal artery-to-middle cerebral artery bypass and encephalo-duro-myoarterio-pericranial synangiosis) for hemorrhagic MMD. At 3 months post-surgery, digital subtraction angiography showed a pseudoaneurysm in the right MMA. Transdural anastomosis to the parietal and occipital lobes was opacified at the distal MMA of the pseudoaneurysm. Intra-aneurysmal coil embolization was performed for preservation of transdural anastomosis. The postoperative course was uneventful. At 1 month post-embolization, angiography revealed an entirely occluded pseudoaneurysm. Conclusion: An increase in blood flow in the MMA due to bypass surgery may accelerate aneurysm development by increasing the hemodynamic stress. This case suggested that intra-aneurysmal embolization may be a potential treatment.

Endoscopic third ventriculostomy for patients with Blake's pouch cyst with adult-onset hydrocephalus: Importance of improved cerebrospinal fluid flow in the prepontine cistern - A case report.

Background: Blake's pouch cyst (BPC) is a posterior fossa cystic malformation that commonly occurs in children with rare adult onset. Herein, we report a case of adult onsets BPC. Case Description: A 61-year-old man presented with gait and cognitive disturbance. Preoperative magnetic resonance imaging (MRI) revealed scarring in the prepontine cistern, and cine phase-contrast MRI revealed no pulsation. Endoscopic third ventriculostomy (ETV) was performed with opening the scarring in the prepontine cistern. Postoperative cine phase-contrast MRI revealed that cerebrospinal fluid (CSF) flow in the prepontine cistern improved, resolving the patient's symptoms. Conclusion: We report a case of adult-onset BPC. The mechanism by which is becomes symptomatic is still unclear. We opened the scar in prepontine cistern in addition to ETV with good results. In this report, we discussed the importance of the improvement in CSF dynamics in the prepontine cistern.