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OBJECTIVE Magnetic resonance imaging–guided focused ultrasound (MRgFUS) is a novel and useful treatment for essential tremor (ET); however, the factors impacting treatment outcome are unknown. The authors conducted this study to determine the factors affecting the outcome of MRgFUS. METHODS From May 2016 through August 2017, 15 patients with ET were admitted to Ohnishi Neurological Center and treated with MRgFUS. To determine the factors impacting treatment outcome, the authors retrospectively studied correlations between the Clinical Rating Scale for Tremor (CRST) improvement rate and age, disease duration, baseline CRST score, skull density ratio (SDR), skull volume, maximum delivered energy, or maximum temperature. RESULTS The mean CRST score was 18.5 ± 5.8 at baseline and 4.6 ± 5.7 at 1 year. The rate of improvement in the CRST score was 80% ± 22%. Younger age and lower baseline CRST score were correlated with a higher CRST improvement rate (p = 0.025 and 0.007, respectively). To obtain a CRST improvement rate ≥ 50%, a maximum temperature ≥ 55°C was necessary. There was no correlation between SDR and CRST improvement rate (p = 0.658). A lower SDR and higher skull volume required significantly higher maximum delivered energy (p = 0.014 and 0.016, respectively). A higher maximum temperature was associated with a significantly larger lesion volume (p = 0.026). CONCLUSIONS Younger age and lower baseline CRST score were favorable outcome factors. It is important to assess predictive factors when applying MRgFUS.

BACKGROUND Several feasibility studies and a randomized, controlled, multicenter trial have demonstrated the safety and efficacy of unilateral transcranial magnetic resonance-guided focused ultrasound (FUS) lesioning of the ventral intermediate thalamic nucleus in treating essential tremor. OBJECTIVE To evaluate the safety and efficacy of FUS thalamotomy in a Japanese patient cohort through a prospective, multicenter, single-arm confirmatory trial. METHODS A total of 35 patients with disabling refractory essential tremor underwent unilateral FUS thalamotomy and were followed up for 12 post-treatment months. Safety was measured as the incidence and severity of treatment-related adverse events. Efficacy was measured as the tremor severity and quality of life improvements using the Clinical Rating Scale for Tremor and Questionnaire for Essential Tremor. RESULTS The mean skull density ratio (SDR) was 0.47. There was a significant decrease in the mean postural tremor score of the treated hand from baseline to 12 mo by 56.4% (95% CI: 46.7%-66.1%; P

BACKGROUND Compared with several reports of cerebral vasospasm after clipping for unruptured cerebral aneurysm, only one study to date has reported cerebral vasospasm after coil embolization. Herein, the authors report a rare case of cerebral vasospasm after coil embolization for unruptured cerebral aneurysm. OBSERVATIONS A 58-year-old woman with an unruptured anterior communicating artery aneurysm was referred to our department. Stent-assisted coil embolization was performed for the aneurysm, and no obvious adverse events were observed on cerebral angiography obtained immediately after the operation. However, the patient developed mild headache and slight restlessness soon after the operation and new-onset disorientation, left hemispatial neglect, and left hemiplegia the day after the operation. Emergency brain magnetic resonance imaging and cerebral angiography indicated vasospasm in the right middle cerebral artery, and intra-arterial injection of fasudil hydrochloride hydrate was performed to dilate the middle cerebral artery. Blood flow in the middle cerebral artery immediately improved, and she was discharged without neurological deficits 8 days after the operation. LESSONS Immediate intervention is necessary to prevent cerebral infarction in patients with cerebral vasospasm, which may occur even after coil embolization for unruptured cerebral aneurysm.

Background A rare case of a solitary fibrous tumor/hemangiopericytoma (SFT/HPC) expanding the superior and inferior cerebellar tentorium is described. Case description A 28-year-old male presented with convulsions. Magnetic resonance imaging revealed a tumor around the right cerebellar tentorium. The tumor was completely removed after embolization of the feeding arteries, and the pathological diagnosis was World Health Organization grade III SFT/HPC. The patient's postoperative course was uneventful, and there was no recurrence or extracranial metastasis at 1.5 years following the operation. Conclusions It was possible to fully remove the SFT/HPC tumor; however, strict observation of the whole body is needed because of the possibility of recurrence and extracranial metastasis.

Introduction: Essential tremor is the most common movement disorder in adults. Bilateral symptoms are typical; however, bilateral thalamotomy for essential tremor is associated with a high probability of adverse events. We retrospectively investigated the efficacy and safety of staged bilateral ventral intermediate nucleus thalamotomy for refractory essential tremor using magnetic resonance imaging-guided focused ultrasound. Methods: We enrolled 5 consecutive patients with refractory essential tremor between September 2016 and March 2020. Patients underwent a second operation at least 1 year after the first operation. The second lesion was created asymmetrically to the first lesion. Results: Mean patient age was 57.6 years, and the mean interval between the 2 operations was 27.8 months. The second lesion center was superior to the first lesion in all patients. The mean baseline, second preoperative, and second postoperative Clinical Rating Scale for Tremor total scores were 63.6, 49.2, and 21.8, respectively. The mean baseline, second preoperative, and second postoperative Clinical Rating Scale for Tremor part C scores were 18.4, 8.2, and 2.6, respectively. One patient had permanent adverse events of slight dysarthria and discomfort in the tongue. No patient experienced dysphagia or cognitive dysfunction after the second operation. Four of the 5 patients were satisfied with the results of the bilateral treatment, including the patient who had permanent adverse events. Conclusions: Magnetic resonance imaging-guided focused ultrasound is an effective method for bilateral thalamotomy when adhering to the following considerations: (1) asymmetrical lesions are created and (2) sufficient interval (>1 year) between operations.

A 9-French (Fr) sheath is routinely used during mechanical thrombectomy (MT) for treating acute ischemic stroke (AIS). However, the use of a large sheath is a risk factor for access site complications (ASCs). Previous studies focused on preventing intracranial complications, and only a few have explored ASCs. We investigated the technical feasibility and efficacy of a sheathless procedure for AIS (SPAIS) that uses a 9-Fr balloon-guiding catheter as a guiding sheath to reduce the sheath size and prevent ASCs during MT.We retrospectively analyzed the data of 133 patients who underwent MT at our center. Patients treated between January 2015 and August 2017 received conventional treatment (C) using a 9-Fr sheath, and SPAIS was attempted in patients treated between September 2017 and October 2019. We first assessed the technical feasibility of SPAIS, and subsequently compared the incidence of ASCs between the SPAIS and C groups. Routine postsurgical ASC assessments using duplex ultrasonography were performed during the post-MT bed-rest period.The technical success rate of SPAIS was 97.6% (81 of 83 patients). The incidence of ASCs was significantly lower in the SPAIS group (2 of 81, 2.5%) than in the C group (7 of 52, 13.4%) (P0.05). Moreover, developed pseudoaneurysms in the SPAIS group showed significantly faster hemostasis than those in the C group (mean 20 minutes vs. 32 minutes; P0.05).SPAIS is a feasible technique that effectively reduces MT-associated ASCs; thus, this approach should be adopted to improve patient outcomes.

The relationship between stroke etiology and clot pathology remains controversial.We performed histological analysis of clots retrieved from 52 acute ischemic stroke patients using hematoxylin and eosin staining and immunohistochemistry (CD42b and oxidative/hypoxic stress markers). The correlations between clot composition and the stroke etiological group (i.e., cardioembolic, cryptogenic, or large artery atherosclerosis) were assessed.Of the 52 clots analyzed, there were no significant differences in histopathologic composition (e.g., white blood cells, red blood cells, fibrin, and platelets) between the 3 etiological groups (P = .92). By contrast, all large artery atherosclerosis clots showed a localized pattern with the oxidative stress marker 4-hydroxyl-2-nonenal (P.01). From all 52 clots, 4-hydroxyl-2-nonenal expression patterns were localized in 28.8% of clots, diffuse in 57.7% of clots, and no signal in 13.5% of clots.A localized pattern of 4-hydroxyl-2-nonenal staining may be a novel and effective marker for large artery atherosclerosis (sensitivity 100%, specificity 82%).

Background Trigeminal neuralgia (TN) resulting from a dural arteriovenous fistula (DAVF) are rare. A case of cavernous sinus dural arteriovenous fistula (CSDAVF) in a patient with TN that resolved immediately after transvenous embolization (TVE) is described. Case Description A 75-year-old woman presented with continuous facial pain. On time-of-flight magnetic resonance angiography (MRA), a CSDAVF was suspected, and digital subtraction angiography (DSA) showed a CSDAVF. The TN completely resolved immediately after TVE, with no recurrence. Follow-up MRA showed complete obliteration of the fistula 13 months after TVE. Conclusions The pulsatile flow at the posteromedial part of the cavernous sinus might have compressed the upper aspect of the Gasserian ganglion, causing TN. Disappearance of pulsatile flow after TVE might result in complete resolution of TN.

We studied one frontal lobe tumor and multiple spinal cord tumors (one in an extramedullary location) that had been resected from a 24-year-old man. The frontal lobe tumor was well demarcated and non-infiltrating, and consisted of eosinophilic, elongated fibrillary cells arranged in a fascicular pattern. A similar histology was reproduced in the spinal cord tumors, with additional areas showing standard features of ependymoma. Immunohistochemical and ultrastructural observations revealed that all the tumors were ependymal in nature with positivity for GFAP and epithelial membrane antigen and negativity for oligodendrocyte transcription factor 2, showing intra- and intercellular microrosettes, leading us to a diagnosis of tanycytic ependymoma for the frontal lobe tumor and tanycytic ependymoma with ordinary ependymomatous component for the spinal cord tumors. The spinal extramedullary tumor was a schwannoma. Importantly, a heterozygous truncating mutation in the NF2 gene was identified in the blood lymphocytes from the patient. It is known that multiple nervous system tumors can occur in neurofibromatosis type 2 (NF2), which is caused by mutation in the NF2 gene, and that occurrence of ependymoma, including the tanycytic variant, can be associated with this genetic condition. The present case provides further information about the clinicopathology of tanycytic ependymoma with details of the immunohistochemical, ultrastructural and genetic features.

We studied one frontal lobe tumor and multiple spinal cord tumors (one in an extramedullary location) that had been resected from a 24-year-old man. The frontal lobe tumor was well demarcated and non-infiltrating, and consisted of eosinophilic, elongated fibrillary cells arranged in a fascicular pattern. A similar histology was reproduced in the spinal cord tumors, with additional areas showing standard features of ependymoma. Immunohistochemical and ultrastructural observations revealed that all the tumors were ependymal in nature with positivity for GFAP and epithelial membrane antigen and negativity for oligodendrocyte transcription factor 2, showing intra- and intercellular microrosettes, leading us to a diagnosis of tanycytic ependymoma for the frontal lobe tumor and tanycytic ependymoma with ordinary ependymomatous component for the spinal cord tumors. The spinal extramedullary tumor was a schwannoma. Importantly, a heterozygous truncating mutation in the NF2 gene was identified in the blood lymphocytes from the patient. It is known that multiple nervous system tumors can occur in neurofibromatosis type 2 (NF2), which is caused by mutation in the NF2 gene, and that occurrence of ependymoma, including the tanycytic variant, can be associated with this genetic condition. The present case provides further information about the clinicopathology of tanycytic ependymoma with details of the immunohistochemical, ultrastructural and genetic features.