Publications by authors named "Haruhiko Kishima"

166 Publications

Maintenance of WT1 expression in tumor cells is associated with a good prognosis in malignant glioma patients treated with WT1 peptide vaccine immunotherapy.

Cancer Immunol Immunother 2021 Jun 5. Epub 2021 Jun 5.

Department of Neurosurgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi-dori, Hirokoji-agaru, Kamigyo-ku, Kyoto, 602-8566, Japan.

We have previously revealed the overexpression of Wilms' tumor gene 1 (WT1) in malignant glioma and developed WT1 peptide vaccine cancer immunotherapy. A phase II clinical trial indicated the clinical efficacy of the WT1 peptide vaccine for recurrent malignant glioma. Here, we aimed to investigate the immunological microenvironment in glioma tissues before and after WT1 peptide vaccine treatment. Paired tissue samples were obtained from 20 malignant glioma patients who had received the WT1 peptide vaccine for > 3 months and experienced tumor progression, confirmed radiographically and/or clinically, during vaccination. We discovered that the expression of WT1 and HLA class I antigens in the tumor cells significantly decreased after vaccination. Maintenance of WT1 expression, which is the target molecule of immunotherapy, in tumor cells during the vaccination period was significantly associated with a longer progression-free and overall survival. A high expression of HLA class I antigens and low CD4/CD8 tumor-infiltrating lymphocytes (TIL) ratio in pre-vaccination specimens, were also associated with a good prognosis. No statistically significant difference existed in the number of infiltrating CD3 or CD8 T cells between the pre- and post-vaccination specimens, whereas the number of infiltrating CD4 T cells significantly decreased in the post-vaccination specimens. This study provides insight into the mechanisms of intra-tumoral immune reaction/escape during WT1 peptide vaccine treatment and suggests potential clinical strategies for cancer immunotherapy.
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http://dx.doi.org/10.1007/s00262-021-02954-zDOI Listing
June 2021

Mass Spectrometric Enzyme Histochemistry for Choline Acetyltransferase Reveals Acetylcholine Synthesis in Rodent Brain and Spinal Cord.

ACS Chem Neurosci 2021 Jun 2. Epub 2021 Jun 2.

Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

Choline acetyltransferase (ChAT), responsible for the synthesis of acetylcholine, plays an important role in neurotransmission. However, no method to visualize the ChAT activity in tissues has been reported to date. In this study, mass spectrometry imaging (MSI) was used to visualize ChAT activity , which is difficult with conventional enzyme histochemistry. By using choline chloride-trimethyl-d9 (choline-d9) as a substrate and simultaneously supplying an inhibitor of cholinesterase to tissues, we succeeded in directly visualizing the ChAT activity in the rodent brain and spinal cord. The findings revealed heterogeneous ChAT activity in the striatum of the mouse brain and in the spinal lower motor neurons that connect the anterior horn to the ventral root. Furthermore, extending the developed method to spinal cord injury (SCI) model mice revealed the site-specific effect of primary and secondary injury on ChAT activity. This study shows that the MSI-based enzyme histochemistry of ChAT could be a useful tool for studying cholinergic neurons.
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http://dx.doi.org/10.1021/acschemneuro.0c00720DOI Listing
June 2021

An older thrombus delays reperfusion after mechanical thrombectomy for ischemic stroke.

Thromb Haemost 2021 Jun 2. Epub 2021 Jun 2.

Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Suita, Japan.

Background: Thrombosis is a dynamic process, and a thrombus undergoes physical and biochemical changes that may alter its response to reperfusion therapy. This study assessed whether thrombus age influenced reperfusion quality and outcomes after mechanical thrombectomy for cerebral embolism.

Methods: We retrospectively evaluated 185 stroke patients and thrombi that were collected during mechanical thrombectomy at three stroke centers. Thrombi were pathologically classified as fresh or older based on their granulocytes' nuclear morphology and organization. Thrombus components were quantified, and the extent of NETosis (the process of neutrophil extracellular trap formation) was assessed using the density of citrullinated histone H3-positive cells. Baseline patient characteristics, thrombus features, endovascular procedures, and functional outcomes were compared according to thrombus age.

Results: Fresh thrombi were acquired from 43 patients, and older thrombi were acquired from 142 patients. Older thrombi had a lower erythrocyte content (P<0.001) and higher extent of NETosis (P=0.006). Restricted mean survival time analysis revealed that older thrombi were associated with longer puncture-to-reperfusion times (difference: 15.6 minutes longer for older thrombi, P=0.002). This association remained significant even after adjustment for erythrocyte content and the extent of NETosis (adjusted difference: 10.8 min, 95% CI: 0.6-21.1 min, P=0.039). Compared with fresh thrombi, older thrombi required more device passes before reperfusion (P<0.001) and were associated with poorer functional outcomes (adjusted common OR: 0.49, 95% CI: 0.24-0.99).

Conclusions: An older thrombus delays reperfusion after mechanical thrombectomy for ischemic stroke. Adding therapies targeting thrombus maturation may improve the efficacy of mechanical thrombectomy.
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http://dx.doi.org/10.1055/a-1522-4507DOI Listing
June 2021

Determination of Brain Tumor Recurrence using C-methionine Positron Emission Tomography after Radiotherapy.

Cancer Sci 2021 Jun 1. Epub 2021 Jun 1.

Department of Nuclear Medicine, Hokkaido University Hospital, Sapporo, Japan.

We conducted a prospective multicenter trial to compare the usefulness of C-methioinine (MET) and F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for identifying tumor recurrence. Patients with clinically suspected tumor recurrence after radiotherapy underwent both C-MET and F-FDG PET. When a lesion showed a visually detected uptake of either tracer, it was surgically resected for histopathological analysis. Patients with a lesion negative to both tracers were revaluated by magnetic resonance imaging (MRI) at three months after the PET studies. The primary outcome measure was the sensitivity of each tracer in cases with histopathologically confirmed recurrence, as determined by the McNemar test. Sixty-one cases were enrolled, and 56 cases could be evaluated. The 38 cases where the lesions showed uptake of either C-MET or F-FDG underwent surgery; and 32 of these cases were confirmed to be subject to recurrence. Eighteen cases where the lesions showed uptake of neither tracer received follow-up MRI; the lesion size increased in 1 of these cases. Among the cases with histologically confirmed recurrence, the sensitivities of C-MET PET and F-FDG PET were 0.97 (32/33, 95% CI: 0.85-0.99) and 0.48 (16/33, 95% CI: 0.33-0.65), respectively, and the difference was statistically significant (p<0.0001). The diagnostic accuracy of C-MET PET was significantly better than that of F-FDG PET (87.5% vs. 69.6%, p=0.033). No examination-related adverse events were observed. The results of the study demonstrated that C-MET PET was superior to F-FDG PET for discriminating between tumor recurrence and radiation-induced necrosis.
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http://dx.doi.org/10.1111/cas.15001DOI Listing
June 2021

Ophthalmic Artery Flow Pattern-related Stump Pressure and Ischemic Tolerance during Balloon Test Occlusion of the Internal Carotid Artery.

Neurol Med Chir (Tokyo) 2021 May 26. Epub 2021 May 26.

Department of Neurosurgery, Osaka University Graduate School of Medicine.

Very few studies have described the blood flow pattern in the ipsilateral ophthalmic artery (OphA) during internal carotid artery (ICA) balloon test occlusion performed to estimate the risk of cerebral ischemia associated with therapeutic ICA sacrifice. This study aimed to investigate the relationship between ipsilateral OphA flow patterns just after ICA temporary occlusion and balloon test occlusion findings. We retrospectively reviewed 32 balloon test occlusion procedures performed at our institution between 2010 and 2019, and analyzed the OphA flow patterns and the conventional balloon test occlusion assessment items: neurological symptoms, stump pressure, stump-pressure ratio, collateral circulations, and venous phase delay. The flow patterns were categorized as type I (retrograde flow reaching the middle cerebral artery [MCA]), type II (retrograde flow to the ICA not reaching the MCA), or type III (no retrograde flow). Tolerance to balloon test occlusion was observed in 4/21 patients (19.0%), 4/6 patients (66.7%), and all five patients with types I, II, and III flows, respectively. The mean pressure ratios during balloon test occlusion in flow types I, II, and III were 35.6% ± 3.5%, 56.4% ± 6.5%, and 69.4% ± 7.1%, respectively (P <0.001). The mean stump pressures in flow types I, II, and III were 36.2 ± 3.6 mmHg, 46.6 ± 6.7 mmHg, and 66.6 ± 7.3 mmHg, respectively (P = 0.003). The mean venous phase delay in flow types I, II, and III were 0.99 ± 0.14 s, 0.25 ± 0.25 s, and 0.0 ± 0.28 s, respectively (P = 0.004). All the above variables showed significant flow-related differences. These results suggest that the OphA flow patterns may provide an additional diagnostic criterion for balloon test occlusion.
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http://dx.doi.org/10.2176/nmc.oa.2020-0406DOI Listing
May 2021

The Impact of 5-Year Tumor Doubling Time to Predict the Subsequent Long-Term Natural History of Asymptomatic Meningiomas.

World Neurosurg 2021 May 18. Epub 2021 May 18.

Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan.

Objective: Meningiomas are the most frequent primary brain tumors. The long-term natural history of asymptomatic meningiomas remains unclear and difficult to predict accurately, however. The purpose of this study was to determine the subsequent course of asymptomatic meningiomas preceded by 5 years of no treatment.

Methods: We retrospectively studied patients with radiologically suspected intracranial asymptomatic meningiomas preceded by 5 years of no treatment. We volumetrically measured the lesions' chronological changes during the initial 5 years to obtain the 5-year tumor doubling time (5y-TdT).

Results: A total of 201 cases met the inclusion criteria. They were further divided into 3 subgroups: those who remained asymptomatic (group A; 174 cases), those who developed neurological symptoms and underwent treatment (group B; 8 cases), and those who received intentional intervention for a preventative reason (group C; 19 cases). 5y-TdT of group B (median: 46.5 months) was significantly shorter than that of group A (median: 216.3 months) (P < 0.001). Progression-free survival (PFS) was significantly different between tumors that exhibited 5y-TdT ≥ 98.8 months and <98.8 months (P < 0.001). When we combined groups B and C and set the PFS endpoint as either disease progression or treatment, we found that more than 20% of patients would require treatment within 15 years.

Conclusions: The present study revealed the subsequent course of asymptomatic meningiomas after 5 years of no treatment and demonstrated that 5y-TdT is useful to detect patients who may require treatment.
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http://dx.doi.org/10.1016/j.wneu.2021.05.023DOI Listing
May 2021

A Direct Aspiration First Pass Technique for Basilar Artery Occlusion Caused by Elastic-hard Tumor Embolus via the Pulmonary Vein by Metastatic Prostate Adenocarcinoma: A Case Report.

NMC Case Rep J 2021 Apr 2;8(1):95-100. Epub 2021 Apr 2.

Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.

Basilar artery occlusion (BAO) accounts for only 1% of all strokes, and cerebral infarction resulting from tumor emboli has been infrequently demonstrated; therefore, few reports described BAO due to tumor embolus and its treatment experience. We report here an 83-year-old man with an acute BAO caused by embolized lung tumor invading right pulmonary vein that was revealed as metastasis of prostate adenocarcinoma. The patient underwent rapid recanalization through acute thrombectomy with a direct aspiration first pass technique (ADAPT) with Penumbra catheter. Successful recanalization was achieved in reperfusion grade of thrombolysis in cerebral infarction (TICI) 2b, and the embolus revealed a highly elastic hard tumorous mass of which texture was too tough to be caught by stent retriever. Immunohistopathologic examination of the embolus revealed adenocaricinoma of the prostate. In spite of that the recanalization was obtained, the patient died of the brain stem infarction after 7 days from the onset. We experienced a rare case of acute BAO caused by embolized prostate cancer metastasizing lung and invading pulmonary vein. When we face to patients with lung tumor invading pulmonary vein, tumor embolus should have been strongly considered and aspiration thrombectomy may be safer and more effective for the condition because of the difficulty of predicting an embolus's texture before treatment.
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http://dx.doi.org/10.2176/nmccrj.cr.2020-0069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116921PMC
April 2021

Testing of Newly Developed Wide-Field Dual-Array Suprachoroidal-Transretinal Stimulation Prosthesis in Dogs.

Transl Vis Sci Technol 2021 Mar;10(3):13

Department of Ophthalmology, Graduate School of Medicine, Osaka University, Osaka, Japan.

Purpose: This study was conducted to investigate the feasibility of a newly developed wide-field dual-array suprachoroidal-transretinal stimulation (STS) prosthesis in dogs and to examine its biocompatibility and stability over a 4-month period.

Methods: Three types of STS dual arrays were designed and tested. The STS dual-array was implanted into a scleral pocket of the left eye of six healthy beagle dogs. Ophthalmic examinations, fundus photography, fluorescein angiography (FA), electroretinography (ERG), and functional testing of this system were conducted postoperatively. The dogs were euthanatized at the end of the experiment, and their eyes were enucleated and histologically examined.

Results: All prostheses were successfully implanted without complications, and no serious adverse event occurred during the postoperative period. Fundus photographs and FA showed no serious damage in the retina surrounding the arrays. The ERGs recorded from the implanted eyes showed no significant differences from those from control eyes. Histological evaluations demonstrated good preservation of the retina over the array. However, system failure occurred in 50% of the dogs owing to dog-specific habits.

Conclusions: Implantation of this prosthesis system in dogs is feasible and can be performed without significant damage to the eye. The biocompatibility and stability of the array were good during the observation period, but the low durability of the system against dogs (not humans) is an issue to be resolved in the future.

Translational Relevance: This study suggests that this wide-field dual-array prosthesis might widen the visual field and might be useful for patients with retinitis pigmentosa.
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http://dx.doi.org/10.1167/tvst.10.3.13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961109PMC
March 2021

Swallowing-related neural oscillation: an intracranial EEG study.

Ann Clin Transl Neurol 2021 Jun 5;8(6):1224-1238. Epub 2021 May 5.

Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan.

Objective: Swallowing is a unique movement due to the indispensable orchestration of voluntary and involuntary movements. The transition from voluntary to involuntary swallowing is executed within milliseconds. We hypothesized that the underlying neural mechanism of swallowing would be revealed by high-frequency cortical activities.

Methods: Eight epileptic participants fitted with intracranial electrodes over the orofacial cortex were asked to swallow a water bolus and cortical oscillatory changes, including the high γ band (75-150 Hz) and β band (13-30 Hz), were investigated at the time of mouth opening, water injection, and swallowing.

Results: Increases in high γ power associated with mouth opening were observed in the ventrolateral prefrontal cortex (VLPFC) with water injection in the lateral central sulcus and with swallowing in the region along the Sylvian fissure. Mouth opening induced a decrease in β power, which continued until the completion of swallowing. The high γ burst of activity was focal and specific to swallowing; however, the β activities were extensive and not specific to swallowing. In the interim between voluntary and involuntary swallowing, swallowing-related high γ power achieved its peak, and subsequently, the power decreased.

Interpretation: We demonstrated three distinct activities related to mouth opening, water injection, and swallowing induced at different timings using high γ activities. The peak of high γ power related to swallowing suggests that during voluntary swallowing phases, the cortex is the main driving force for swallowing as opposed to the brain stem.
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http://dx.doi.org/10.1002/acn3.51344DOI Listing
June 2021

Rostro-caudal different energy metabolism leading to differences in degeneration in spinal cord injury.

Brain Commun 2021 28;3(2):fcab058. Epub 2021 Mar 28.

Department of Research Promotion and Management, National Cerebral and Cardiovascular Center, Osaka, Japan.

Spinal cord injury gradually spreads away from the epicentre of injury. The rate of degeneration on the rostral side of the injury differs from that on the caudal side. Rostral degeneration is an immediate process, while caudal degeneration is delayed. In this study, we demonstrated that the rostro-caudal differences in energy metabolism led to differences in the spread of degeneration in early thoracic cord injury using imaging. The blood flow at the rostral side of the injury showed ischaemia-reperfusion, while the caudal side presented stable perfusion. The rostral side had an ATP shortage 20 min after spinal cord injury, while the ATP levels were maintained on the caudal side. Breakdown products of purine nucleotides were accumulated at both sides of injury 18 h after spinal cord injury, but the principal metabolites in the tricarboxylic acid cycle and glycolytic pathway were elevated on the caudal side. Although the low-ATP regions expanded at the rostral side of injury until 24 h after spinal cord injury, the caudal-side ATP levels were preserved. The low-ATP regions on the rostral side showed mitochondrial reactive oxygen species production. Administration of 2-deoxy-d-glucose as a glycolysis inhibitor decreased the caudal ATP levels and expanded the low-ATP regions to the caudal side until 24 h after spinal cord injury. These results suggest that deficits in the glycolytic pathway accelerate the caudal degeneration, while immediate rostral degeneration is exacerbated by oxidative stress in early thoracic cord injury.
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http://dx.doi.org/10.1093/braincomms/fcab058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066884PMC
March 2021

Phase-amplitude coupling of ripple activities during seizure evolution with theta phase.

Clin Neurophysiol 2021 Jun 26;132(6):1243-1253. Epub 2021 Mar 26.

Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan; Endowed Research Department of Clinical Neuroengineering, Global Center for Medical Engineering and Informatics, Osaka University, Suita 565-0871, Japan; Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan.

Objective: High-frequency activities (HFAs) and phase-amplitude coupling (PAC) are key neurophysiological biomarkers for studying human epilepsy. We aimed to clarify and visualize how HFAs are modulated by the phase of low-frequency bands during seizures.

Methods: We used intracranial electrodes to record seizures of focal epilepsy (12 focal-to-bilateral tonic-clonic seizures and three focal-aware seizures in seven patients). The synchronization index, representing PAC, was used to analyze the coupling between the amplitude of ripples (80-250 Hz) and the phase of lower frequencies. We created a video in which the intracranial electrode contacts were scaled linearly to the power changes of ripple.

Results: The main low frequency band modulating ictal-ripple activities was the θ band (4-8 Hz), and after completion of ictal-ripple burst, δ (1-4 Hz)-ripple PAC occurred. The ripple power increased simultaneously with rhythmic fluctuations from the seizure onset zone, and spread to other regions.

Conclusions: Ripple activities during seizure evolution were modulated by the θ phase. The PAC phenomenon was visualized as rhythmic fluctuations.

Significance: Ripple power associated with seizure evolution increased and spread with fluctuations. The θ oscillations related to the fluctuations might represent the common neurophysiological processing involved in seizure generation.
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http://dx.doi.org/10.1016/j.clinph.2021.03.007DOI Listing
June 2021

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI.

J Vis Exp 2021 03 19(169). Epub 2021 Mar 19.

Department of Neurosurgery, Osaka University Graduate School of Medicine.

Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), EEG-fMRI, combines the complementary properties of scalp EEG (good temporal resolution) and fMRI (good spatial resolution) to measure neuronal activity during an electrographic event, through hemodynamic responses known as blood-oxygen-level-dependent (BOLD) changes. It is a non-invasive research tool that is utilized in neuroscience research and is highly beneficial to the clinical community, especially for the management of neurological diseases, provided that proper equipment and protocols are administered during data acquisition. Although recording EEG-fMRI is apparently straightforward, the correct preparation, especially in placing and securing the electrodes, is not only important for safety but is also critical in ensuring the reliability and analyzability of the EEG data obtained. This is also the most experience-demanding part of the preparation. To address these issues, a straightforward protocol that ensures data quality was developed. This article provides a step-by-step guide for acquiring reliable EEG data during EEG-fMRI using this protocol that utilizes readily available medical products. The presented protocol can be adapted to different applications of EEG-fMRI in research and clinical settings, and may be beneficial to both inexperienced and expert operators.
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http://dx.doi.org/10.3791/62247DOI Listing
March 2021

Multiple stenting using anchoring technique with balloon guiding catheter for common carotid artery dissection after aortic arch replacement: A case report.

Int J Surg Case Rep 2021 Apr 11;81:105748. Epub 2021 Mar 11.

Department of Neurosurgery, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.

Introduction And Importance: Common carotid artery (CCA) dissection is a minor complication during aortic arch replacement (AAR). Although endovascular treatment can be considered for symptomatic CCA dissection despite internal therapy, no report has mentioned about carotid stenting for CCA dissection after vascular graft replacement.

Case Presentation: The patient was a 68-year-old man presented with recurrent transient right hemiparesis. CECT and arteriography showed the progressive CCA dissection associated with AAR and decreased cerebral blood flow. MRI showed no evidence of infarction. Epilepsy, electrolyte abnormalities, hypoglycemia, spinal cord disease were considered as differential diagnoses of transient paralysis, but all were negative. Considering these findings, we diagnosed the patient with transient ischemic attacks (TIAs) caused by CCA dissection. He was treated with multiple stents deployed through vascular grafts using anchoring technique with balloon guiding catheter. Angiography demonstrated reconstitution of the CCA and internal carotid artery 1.5 years after the intervention, and no further TIAs were observed. MRI scan showed no evidence of infarction.

Clinical Discussion: After AAR, the alteration of anatomy and lack of elasticity of vascular grafts make it quite difficult to access lesions. The adoption of a distal access catheter (DAC) and balloon inflation of a guiding catheter (BGC) are useful approaches.

Conclusion: To our knowledge, this is the first case report of successful multiple carotid stenting through vascular grafts for the treatment of CCA dissection. The main take-away lessons are the following three.
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http://dx.doi.org/10.1016/j.ijscr.2021.105748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020436PMC
April 2021

Efficacy of endovascular intratumoral embolization for meningioma: assessment using dynamic susceptibility contrast-enhanced perfusion-weighted imaging.

J Neurointerv Surg 2021 Mar 15. Epub 2021 Mar 15.

Neurosurgery, Osaka University School of Medicine Graduate School of Medicine, Suita, Japan.

Background: In preoperative embolization for intracranial meningioma, endovascular intratumoral embolization is considered to be more effective for the reduction of tumorous vascularity than proximal feeder occlusion. In this study, we aimed to reveal different efficacies for reducing tumor blood flow in meningiomas by comparing endovascular intratumoral embolization and proximal feeder occlusion using dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI).

Methods: 28 consecutive patients were included. DSC-PWI was performed before and after embolization for intracranial meningiomas. Normalized tumor blood volume (nTBV) of voxels of interest of whole tumors were measured from the DSC-PWI data before and after embolization. ΔnTBV% was compared between the cases that received intratumoral embolization and proximal feeder occlusion.

Results: ΔnTBV% in the intratumoral embolization group (42.4±29.8%) was higher than that of the proximal feeder occlusion group (15.3±14.3%, p=0.0039). We used three types of embolic materials and ΔnTBV% did not differ between treatments with or without the use of each material: 42.8±42.4% vs 28.7±20.1% for microspheres (p=0.12), 36.1±20.6% vs 28.1±41.1% for n-butyl cyanoacrylate (p=0.33), and 32.3±37.3% vs 34.1±19.0% for bare platinum coils (p=0.77).

Conclusions: The flow reduction effect of intratumoral embolization was superior to that of proximal feeder occlusion in preoperative embolization for intracranial meningioma in an assessment using DSC-PWI.
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http://dx.doi.org/10.1136/neurintsurg-2020-017116DOI Listing
March 2021

A case of meningolacrimal artery aneurysm associated with meningioma.

Surg Neurol Int 2021 17;12:61. Epub 2021 Feb 17.

Department of Neurosurgery, Osaka University Graduate School of Medicine, Osaka, Japan.

Background: Intraorbital aneurysms are rare, and most of them originate from the ophthalmic arteries. Herein, we report a case of meningolacrimal artery aneurysm associated with a meningioma.

Case Description: A 55-year-old woman had a frontal convexity meningioma identified by brain magnetic resonance imaging during a checkup. Cerebral angiography revealed the middle meningeal artery as a feeding artery as well as the presence of an aneurysm associated with the meningolacrimal artery. Embolization of the feeding artery was performed before the removal of the meningioma. The meningioma was resected, and the aneurysm was removed with a bone flap. The patient was discharged without any complications.

Conclusion: We report a meningolacrimal artery aneurysm associated with a meningioma. Embolizing the feeding artery of the aneurysm was helpful in safely resecting the meningioma.
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http://dx.doi.org/10.25259/SNI_811_2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7911222PMC
February 2021

Impact of Inversion Time for FLAIR Acquisition on the T2-FLAIR Mismatch Detectability for -Mutant, Non-CODEL Astrocytomas.

Front Oncol 2020 14;10:596448. Epub 2021 Jan 14.

Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan.

The current research tested the hypothesis that inversion time (TI) shorter than 2,400 ms under 3T for FLAIR can improve the diagnostic accuracy of the T2-FLAIR mismatch sign for identifying mt, non-CODEL astrocytomas. We prepared three different cohorts; 94 MRI from 76 mt, non-CODEL Lower-grade gliomas (LrGGs), 33 MRI from 31 LrGG under the restriction of FLAIR being acquired with TI < 2,400 ms for 3T or 2,016 ms for 1.5T, and 112 MRI from 112 patients from the TCIA/TCGA dataset for LrGG. The presence or absence of the "T2-FLAIR mismatch sign" was evaluated, and we compared diagnostic accuracies according to TI used for FLAIR acquisition. The T2-FLAIR mismatch sign was more frequently positive when TI was shorter than 2,400 ms under 3T for FLAIR acquisition ( = 0.0009, Fisher's exact test). The T2-FLAIR mismatch sign was positive only for mt, non-CODEL astrocytomas even if we confined the cohort with FLAIR acquired with shorter TI ( = 0.0001, Fisher's exact test). TCIA/TCGA dataset validated that the sensitivity, specificity, PPV, and NPV of the T2-FLAIR mismatch sign to identify mt, non-CODEL astrocytomas improved from 31, 90, 79, and 51% to 67, 94, 92, and 74%, respectively and the area under the curve of ROC improved from 0.63 to 0.87 when FLAIR was acquired with shorter TI. We revealed that TI for FLAIR impacts the T2-FLAIR mismatch sign's diagnostic accuracy and that FLAIR scanned with TI < 2,400 ms in 3T is necessary for LrGG imaging.
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http://dx.doi.org/10.3389/fonc.2020.596448DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7841010PMC
January 2021

Anatomical variation of the internal carotid artery and its implication to the endoscopic endonasal translacerum approach.

Head Neck 2021 May 27;43(5):1535-1544. Epub 2021 Jan 27.

Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.

Background: The endoscopic endonasal trans-lacerum approach (EETLA) is useful in handling skull base tumors around inferior petrous apex (IPA); however, its surgical corridor is exclusively a triangular space (supra-eustachian triangle [SET]), between the internal carotid artery (ICA) and eustachian tube.

Methods: We investigated correlation between SET size and extent of resection around the IPA (lateral extent of resection [EOR]) through a retrospective analysis of 15 surgeries using EETLA.

Results: Of 15 cases (9 chordomas, 4 chondrosarcomas, and 2 meningiomas), 20 sides of IPA were affected by the tumor. When being restricted to sides with severe lateral tumor extension beyond the midpoint of petrous ICA (10 sides), the SET size was significantly broader in the group with lateral EOR of ≥90% (p value = 0.019).

Conclusions: The SET size was a powerful index of tumor resectability in EETLA, especially in cases with severe tumor extension. The individual anatomical variations should be considered when determining EETLA application.
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http://dx.doi.org/10.1002/hed.26618DOI Listing
May 2021

Analgesic Effects of Repetitive Transcranial Magnetic Stimulation at Different Stimulus Parameters for Neuropathic Pain: A Randomized Study.

Neuromodulation 2021 Jan 21. Epub 2021 Jan 21.

Department of Neuromodulation and Neurosurgery, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan.

Objectives: The aim of the present study was to investigate the analgesic effects of repetitive transcranial magnetic stimulation over the primary motor cortex (M1-rTMS) using different stimulation parameters to explore the optimal stimulus condition for treating neuropathic pain.

Materials And Methods: We conducted a randomized, blinded, crossover exploratory study. Four single sessions of M1-rTMS at different parameters were administered in random order. The tested stimulation conditions were as follows: 5-Hz with 500 pulses per session, 10-Hz with 500 pulses per session, 10-Hz with 2000 pulses per session, and sham stimulation. Analgesic effects were assessed by determining the visual analog scale (VAS) pain intensity score and Short-Form McGill Pain Questionnaire 2 (SF-MPQ2) score immediately before and immediately after intervention.

Results: We enrolled 22 adults (age: 59.8 ± 12.1 years) with intractable neuropathic pain. Linear-effects models showed significant effects of the stimulation condition on changes in VAS pain intensity (p = 0.03) and SF-MPQ2 (p = 0.01). Tukey multiple comparison tests revealed that 10-Hz rTMS with 2000 pulses provided better pain relief than sham stimulation, with greater decreases in VAS pain intensity (p = 0.03) and SF-MPQ2 (p = 0.02).

Conclusions: The results of this study suggest that high-dose stimulation (specifically, 10-Hz rTMS at 2000 pulses) is more effective than lower-dose stimulation for treating neuropathic pain.
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http://dx.doi.org/10.1111/ner.13328DOI Listing
January 2021

Focused Ultrasound Thalamotomy for Refractory Essential Tremor: A Japanese Multicenter Single-Arm Study.

Neurosurgery 2021 03;88(4):751-757

Department of Neurosurgery, Tokyo Women's Medical University, Tokyo, Japan.

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 < .001), which was maintained at last follow-up. Quality of life improved by 46.3% (mean overall Questionnaire for Essential Tremor score of 17.4 [95% CI: 12.1-22.7]) and there were no severe adverse events. The most frequent adverse event was gait disturbance and all events resolved.

Conclusion: Unilateral FUS thalamotomy allowed significant and sustained tremor relief and improved the quality of life with an outstanding safety profile. The observed safety and efficacy of FUS thalamotomy were comparable to those reported in a previous multicenter study with a low SDR, and inclusion of the low SDR group did not affect effectiveness.
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http://dx.doi.org/10.1093/neuros/nyaa536DOI Listing
March 2021

Clinical evaluation of neuroinflammation in child-onset focal epilepsy: a translocator protein PET study.

J Neuroinflammation 2021 Jan 6;18(1). Epub 2021 Jan 6.

Department of Child Development, United Graduate School of Child Development, Osaka University, Suita, Osaka, Japan.

Background: Neuroinflammation is associated with various chronic neurological diseases, including epilepsy; however, neuroimaging approaches for visualizing neuroinflammation have not been used in the clinical routine yet. In this study, we used the translocator protein positron emission tomography (PET) with [C] DPA713 to investigate neuroinflammation in the epileptogenic zone in patients with child-onset focal epilepsy.

Methods: Patients with intractable focal epilepsy were recruited at the Epilepsy Center of Osaka University; those who were taking any immunosuppressants or steroids were excluded. PET images were acquired for 60 min after intravenous administration of [C] DPA713. The PET image of [C] DPA713 was co-registered to individual's magnetic resonance imaging (MRI), and the standardized uptake value ratio (SUVr) in regions of interest, which were created in non-lesions and lesions, was calculated using the cerebellum as a pseudo-reference region. In the case of epilepsy surgery, the correlation between SUVr in lesions and pathological findings was analyzed.

Results: Twenty-seven patients (mean age: 11.3 ± 6.2 years, male/female: 17/10) were included in this study. Of these, 85.1% showed increased uptake of [C] DPA713 in the focal epileptic lesion. Three patients showed epileptic spasms, suggesting partial seizure onset, and all 18 patients with abnormal lesions on MRI were similarly highlighted by significant uptake of [C] DPA713. DPA713-positive patients had a broad range of etiologies, including focal cortical dysplasia, tumors, infarction, and hippocampal sclerosis. Five out of nine MRI-negative patients showed abnormal [C] DPA713 uptake. The SUVr of [C] DPA713 in lesions was significantly higher than that in non-lesions. In seven patients who underwent epilepsy surgery, increased [C] DPA713 uptake was associated with microglial activation.

Conclusions: This study indicates that [C] DPA713 uptake has valuable sensitivity in the identification of epileptic foci in child-onset focal epilepsy, and inflammation is implicated in the pathophysiology in the epileptic foci caused by various etiologies. Further research is required to establish diagnostic tools for identifying focal epileptogenic zones.
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http://dx.doi.org/10.1186/s12974-020-02055-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789379PMC
January 2021

Activated leukocyte cell adhesion molecule expression correlates with the WNT subgroup in medulloblastoma and is involved in regulating tumor cell proliferation and invasion.

PLoS One 2020 3;15(12):e0243272. Epub 2020 Dec 3.

Department of Neurosurgery, Osaka University Graduate School of Medicine, Osaka, Japan.

Cluster of differentiation (CD) 166 or activated leukocyte cell adhesion molecule (ALCAM) is a transmembrane molecule known to be an intercellular adhesion factor. The expression and function of ALCAM in medulloblastoma (MB), a pediatric brain tumor with highly advanced molecular genetics, remains unclear. Therefore, this study aimed to clarify the significance and functional role of ALCAM expression in MB. ALCAM expression in 45 patients with MB was evaluated by immunohistochemical analysis of formalin-fixed paraffin-embedded clinical specimens and the relationship between ALCAM expression and pathological type/molecular subgroup, such as WNT, SHH, Group 3, and Group 4, was examined. Eight ALCAM positive (18%), seven partially positive (16%), and 30 negative (67%) cases were detected. All seven cases of the WNT molecular subgroup were ALCAM positive and ALCAM expression strongly correlated with this subgroup (P < 0.0001). In addition, functional studies using MB cell lines revealed ALCAM expression affected proliferation and migration as a positive regulator in vitro. However, ALCAM silencing did not affect survival or the formation of leptomeningeal dissemination in an orthotopic mouse model, but did induce a malignant phenotype with increased tumor cell invasion at the dissemination sites (P = 0.0029). In conclusion, our results revealed that ALCAM exhibited highly specific expression in the WNT subgroup of MB. Furthermore, we demonstrated that the cell kinetics of MB cell lines can be altered by the expression of ALCAM.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0243272PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7714159PMC
January 2021

Retrosigmoid Approach in the Supine Position Using ORBEYE: A Consecutive Series of 14 Cases.

Neurol Med Chir (Tokyo) 2021 Jan 26;61(1):55-61. Epub 2020 Nov 26.

Department of Neurosurgery, Kansai Rosai Hospital.

One of the merits of recently introduced exoscopes, including ORBEYE, is that they are superior to a conventional microscope in terms of ergonomic features. Taking advantage of it, the retrosigmoid approach can be performed in the supine position using ORBEYE. We report a consecutive series of 14 operations through the retrosigmoid approach in the supine position using ORBEYE. Fourteen consecutive patients who underwent surgery through the retrosigmoid approach for cerebellopontine (CP) angle lesions in the supine position using ORBEYE were targeted, and surgical outcomes and complications were examined. We evaluated the posture of the operator and the surgical field during this approach compared with those using a conventional microscope. In all 14 cases, all operative procedures were accomplished only using the ORBEYE. There were no operative complications due to this approach. Using ORBEYE, even when the angle of the operative visual axis was horizontal, the operators could manipulate in a comfortable posture. They were not forced to be in an uncomfortable posture that extended their arms, as is often the case with a conventional microscope. Therefore, they could use shorter surgical instruments. As the cerebellum shifted downward with gravity even using slight retraction during this approach, the working space of the surgical field was easily secured. Through this approach, the operators can perform stable microsurgery of CP angle lesions in a comfortable posture. This approach can reduce the burden on the operator and the patient, leading to a refined surgical procedure.
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http://dx.doi.org/10.2176/nmc.tn.2020-0277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7812308PMC
January 2021

TERT promoter mutation confers favorable prognosis regardless of 1p/19q status in adult diffuse gliomas with IDH1/2 mutations.

Acta Neuropathol Commun 2020 11 23;8(1):201. Epub 2020 Nov 23.

Department of Neurosurgery, Dokkyo Medical University, 880, Kitakobayashi, Mibu-City, Tochigi, 321-0293, Japan.

TERT promoter mutations are commonly associated with 1p/19q codeletion in IDH-mutated gliomas. However, whether these mutations have an impact on patient survival independent of 1p/19q codeletion is unknown. In this study, we investigated the impact of TERT promoter mutations on survival in IDH-mutated glioma cases. Detailed clinical information and molecular status data were collected for a cohort of 560 adult patients with IDH-mutated gliomas. Among these patients, 279 had both TERT promoter mutation and 1p/19q codeletion, while 30 had either TERT promoter mutation (n = 24) or 1p/19q codeletion (n = 6) alone. A univariable Cox proportional hazard analysis for survival using clinical and genetic factors indicated that a Karnofsky performance status score (KPS) of 90 or 100, WHO grade II or III, TERT promoter mutation, 1p/19q codeletion, radiation therapy, and extent of resection (90-100%) were associated with favorable prognosis (p < 0.05). A multivariable Cox regression model revealed that TERT promoter mutation had a significantly favorable prognostic impact (hazard ratio = 0.421, p = 0.049), while 1p/19q codeletion did not have a significant impact (hazard ratio = 0.648, p = 0.349). Analyses incorporating patient clinical and genetic information were further conducted to identify subgroups showing the favorable prognostic impact of TERT promoter mutation. Among the grade II-III glioma patients with a KPS score of 90 or 100, those with IDH-TERT co-mutation and intact 1p/19q (n = 17) showed significantly longer survival than those with IDH mutation, wild-type TERT, and intact 1p/19q (n = 185) (5-year overall survival, 94% and 77%, respectively; p = 0.032). Our results demonstrate that TERT promoter mutation predicts favorable prognosis independent of 1p/19q codeletion in IDH-mutated gliomas. Combined with its adverse effect on survival among IDH-wild glioma cases, the bivalent prognostic impact of TERT promoter mutation may help further refine the molecular diagnosis and prognostication of diffuse gliomas.
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http://dx.doi.org/10.1186/s40478-020-01078-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685625PMC
November 2020

[Two Cases of Venous Malformation of the Orbit Treated by Endoscopic Endonasal Surgery].

No Shinkei Geka 2020 Nov;48(11):1043-1049

Department of Neurosurgery, Graduate School of Medicine, Osaka University.

Venous malformation of the orbit(VMO), previously called orbital cavernous hemangioma, has been classified as a vascular malformation according to the International Society for the Study of Vascular Anomalies. Among various surgical approaches for VMO, endoscopic endonasal surgery(EES)has recently been developed, especially for those in the inferomedial quadrant of the orbit. Two 67-year-old and 69-year-old women presented with decreased visual acuity and visual field deficit, respectively. Their CT and MRI scans revealed retrobulbar masses, suggestive of the inferomedial type of VMO. The first case was diagnosed as an intraconal VMO, and subtotal removal was achieved through binostril EES using a two-surgeon four-handed technique after palliative partial resection through a prior frontal craniotomy. In the second case, diagnosed as an extraconal VMO, total en bloc removal was achieved using the same surgical technique as above. In both cases, the visual functions improved after the procedures, with uneventful postoperative courses. Although the inferomedial VMO is an uncommon type, EES is well indicated for this condition. The international consensus of surgical techniques and staging from a surgical point of view should be established in the near future.
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http://dx.doi.org/10.11477/mf.1436204318DOI Listing
November 2020

Burst Spinal Cord Stimulation for the Treatment of Cervical Dystonia with Intractable Pain: A Pilot Study.

Brain Sci 2020 Nov 7;10(11). Epub 2020 Nov 7.

Department of Neurosurgery, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.

Pain is the most common and disabling non-motor symptom in patients with cervical dystonia. Here, we report four patients with painful cervical dystonia in whom burst spinal cord stimulation (SCS) in the cervical region produced sustained and significant improvements in both dystonic pain and motor symptoms. Further studies need to be performed to investigate the clinical efficacy of burst SCS for patients with cervical dystonia.
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http://dx.doi.org/10.3390/brainsci10110827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694959PMC
November 2020

Technical Aspects of SEEG and Its Interpretation in the Delineation of the Epileptogenic Zone.

Neurol Med Chir (Tokyo) 2020 Dec 6;60(12):565-580. Epub 2020 Nov 6.

Department of Neurosurgery, Osaka University Graduate School of Medicine.

Stereo-electroencephalography (SEEG) has gained global popularity in recent years. In Japan, a country in which invasive studies using subdural electrodes (SDEs) have been the mainstream, SEEG has been approved for insurance coverage in 2020 and is expected to gain in popularity. Some concepts supporting SEEG methodology are fundamentally different from that of SDE studies. Clinicians interested in utilizing SEEG in their practice should be aware of those aspects in which they differ. Success in utilizing the SEEG methodology relies heavily on the construction of an a priori hypothesis regarding the putative seizure onset zone (SOZ) and propagation. This article covers the technical and theoretical aspects of SEEG, including the surgical techniques and precautions, hypothesis construction, and the interpretation of the recording, all with the aim of providing an introductory guide to SEEG.
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http://dx.doi.org/10.2176/nmc.st.2020-0176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7803703PMC
December 2020

Transnasal flow reduction in endovascular treatment for anterior cranial fossa dural arteriovenous fistula.

J Surg Case Rep 2020 Oct 20;2020(10):rjaa327. Epub 2020 Oct 20.

Department of Neurosurgery, Osaka University Graduate School of Medicine, Osaka, Japan.

Transarterial embolization (TAE) is a useful option for anterior cranial fossa-dural arteriovenous fistula (ACF-dAVF) as endovascular devices have progressed. Liquid agents are usually injected via a microcatheter positioned just proximal to the shunt pouch beyond the ophthalmic artery; however, high blood flow from the internal maxillary artery (IMA) often impedes penetration of embolic materials into the shunt pouch. Therefore, reducing blood flow from the IMA before embolization can increase the success rate. In the present case, to reduce blood flow from branches of the IMA, we inserted surgical gauze infiltrated with xylocaine and epinephrine into bilateral nasal cavities. Using this method, we achieved curative TAE with minimal damage to the nasal mucosa. Transnasal flow reduction is an easy, effective and minimally invasive method. This method should be considered in the endovascular treatment of ACF-dAVF, especially in patients with high blood flow from theIMA.
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http://dx.doi.org/10.1093/jscr/rjaa327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7573859PMC
October 2020

Surgical Treatment of Brain Metastasis of Extramammary Paget's Disease: A Case Report.

NMC Case Rep J 2020 Sep 17;7(4):189-193. Epub 2020 Sep 17.

Department of Neurosurgery, Osaka National Hospital, National Hospital Organization, Osaka, Osaka, Japan.

Extramammary Paget's disease (EMPD) is a rare form of neoplasm. Metastasis of EMPD to locations other than lymph nodes and intra-epithelial regions is rare; there are a limited number of case reports of metastases to the liver, lung, bone, and brain. We present a rare case of EMPD that metastasized to the brain and was treated with surgical resection. A 66-year-old man presented with a small palpable mass in the scrotum. After 5 years of observation, he was diagnosed with EMPD that metastasized to the lymph nodes and lung. Tumor resection and postoperative chemotherapy were performed. Six months after the last chemotherapy treatment, he presented with a right temporal lobe tumor and underwent surgical resection. Histopathological analysis revealed brain metastasis of EMPD. Three months after surgery, magnetic resonance imaging (MRI) showed local tumor recurrence, and intensity modulated radiation therapy (IMRT) (45 Gy/15 Fr) was performed. Although the metastatic brain tumor was well controlled, the primary tumor progressed. He was provided best supportive care and died 5 months after brain tumor resection. In this report, we present a rare case of brain metastasis of EMPD, treated with surgical resection, and histopathologically confirmed to be metastatic EMPD.
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http://dx.doi.org/10.2176/nmccrj.cr.2019-0292DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7538455PMC
September 2020

Mechanical thrombectomy in acute ischemic stroke patients with left ventricular assist device.

J Neurol Sci 2020 Nov 17;418:117142. Epub 2020 Sep 17.

Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan. Electronic address:

Objectives: As the number of patients with left ventricular assist device (LVAD) implantation has been increasing, treatment of LVAD-related ischemic stroke is becoming a critical issue. We sought to clarify the features of mechanical thrombectomy in LVAD-related stroke with large vessel occlusion.

Methods: In a multi-center, retrospective case-control study, we compared 20 LVAD-related strokes with 33 non-LVAD strokes, all of which had large vessel occlusion in the anterior circulation treated with mechanical thrombectomy. A comparative histopathological examination of the retrieved thrombi was also performed.

Results: Successful reperfusion was achieved in 75% of the LVAD-related strokes. The time from onset to reperfusion was similar to that of non-LVAD strokes, but the total number of device passes required for reperfusion (median, 2.5 versus 1, P = 0.01) and the incidences of post-procedural parenchymal and subarachnoid hemorrhage (25% versus 3%, P = 0.02 and 55% versus 15%, P = 0.01, respectively) were higher in LVAD-related strokes. Symptomatic intracranial hemorrhage occurred in 4 patients (20%) with LVAD-related strokes. The histopathological analysis revealed that the ratio of erythrocyte components was significantly lower in thrombi retrieved from patients with LVAD-related stroke than in those with non-LVAD stroke (19 ± 6% versus 41 ± 17%, P = 0.01).

Conclusions: Mechanical thrombectomy is feasible in patients with LVAD-related stroke. However, repetitive device passes are needed to achieve successful reperfusion mainly because of the structurally organized thrombi, and the higher risk of hemorrhagic complications should be considered, while offering this therapeutic alternative.
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http://dx.doi.org/10.1016/j.jns.2020.117142DOI Listing
November 2020

A Swallowing Decoder Based on Deep Transfer Learning: AlexNet Classification of the Intracranial Electrocorticogram.

Int J Neural Syst 2020 Sep 16:2050056. Epub 2020 Sep 16.

Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan.

To realize a brain-machine interface to assist swallowing, neural signal decoding is indispensable. Eight participants with temporal-lobe intracranial electrode implants for epilepsy were asked to swallow during electrocorticogram (ECoG) recording. Raw ECoG signals or certain frequency bands of the ECoG power were converted into images whose vertical axis was electrode number and whose horizontal axis was time in milliseconds, which were used as training data. These data were classified with four labels (Rest, Mouth open, Water injection, and Swallowing). Deep transfer learning was carried out using AlexNet, and power in the high-[Formula: see text] band (75-150[Formula: see text]Hz) was the training set. Accuracy reached 74.01%, sensitivity reached 82.51%, and specificity reached 95.38%. However, using the raw ECoG signals, the accuracy obtained was 76.95%, comparable to that of the high-[Formula: see text] power. We demonstrated that a version of AlexNet pre-trained with visually meaningful images can be used for transfer learning of visually meaningless images made up of ECoG signals. Moreover, we could achieve high decoding accuracy using the raw ECoG signals, allowing us to dispense with the conventional extraction of high-[Formula: see text] power. Thus, the images derived from the raw ECoG signals were equivalent to those derived from the high-[Formula: see text] band for transfer deep learning.
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http://dx.doi.org/10.1142/S0129065720500562DOI Listing
September 2020