西山 悠也

BACKGROUND: In >70% of patients with hemifacial spasm (HFS), the offending artery is either the anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA), without a tortuous vertebrobasilar artery (VBA). We hypothesized that anchoring perforators around the root exit zone (REZ) of the AICA or PICA might induce vascular deviation and compression. We investigated the occurrence of these perforators from the AICA or PICA and the extent of VBA tortuosity to reveal the pathology of vascular compression. METHODS: This retrospective review included 110 patients after excluding those with vertebral artery (VA) compression alone. The occurrence of perforators was determined according to operative findings within 5 mm of the REZ, and VBA tortuosity was evaluated using MATLAB. We analyzed the association between perforators, VBA tortuosity, and the surgical implications. RESULTS: The occurrence of perforators from the offending AICA or PICA around the REZ was significantly higher in the group without VA compression (Group A) than in the group with VA compression (Group B). VBA tortuosity was significantly lower in Group A. VBA tortuosity was inversely correlated with the presence of AICA or PICA perforators in all 110 patients. Operative results were similar between the groups, although patients with low VBA tortuosity tended to require interposition in decompression procedures. CONCLUSIONS: Anchoring perforators around the REZ play a crucial role in vascular compression for patients with less tortuous VBAs. Moreover, surgeons should be prepared to deal with multiple perforators in a more complicated surgery in cases of less tortuous VBA.

Abstract Background In glioma surgery, both of functional preservation and maximal safe resection are critical, however, neoadjuvant strategy has never been used because of difficulty of tissue sampling without craniotomy. Method In Keio University Hospital, oligodendrogliomas, i.e., diffuse gliomas with IDH mutation and 1p/19q codeletion, with incomplete initial resection have been treated by upfront chemotherapy and subsequent resection after tumor volume decrease (second look resection, SLR) since 2006 (J Neurooncol 124:127-35, 2015). At first, initial radiotherapy was prescribed immediately after chemotherapy or SLR only for the cases with aggressive clinical course or subarachnoid infiltration, however, cases with residual FLAIR abnormality after upfront chemotherapy or SLR were also subjected to initial radiotherapy since 2018. Cases 1) with IDH mutation and 1p/19q codeletion, and 2) without history of either chemotherapy or radiotherapy, and 3) treated with upfront chemotherapy and subsequent resection strategy, were included. Results Thirty nine cases of oligodendroglioma have been treated with the above strategy since 2006. Tumor volume decrease following upfront chemotherapy was 30-35% (median), and 19 tumors underwent SLR. Among the total 39 cases, PFS and OS after initiation of upfront chemotherapy were 81 months and not reached, respectively, and were 64 months and not reached, respectively, among the 32 cases with deferred radiotherapy. Importantly, the majority of tumor recurrence occurred at the residual FLAIR abnormality following upfront chemotherapy. Conclusions Treatment of oligodendrogliomas utilizing neoadjuvant strategy enables 1) decrease of resection volume as compared with initial maximal safe resection, 2) more precise resection, 3) confirmation of the necessity of initial radiotherapy based on the observed efficacy of chemotherapy. Moreover, the study also suggested that 4) invasion front of oligodendroglioma likely withdraw by alkylating agents, and 5) cases with residual FLAIR abnormality following chemotherapy may be appropriate subjects for initial radiotherapy.

Meningiomas are a common pathology in the central nervous system requiring complete surgical resection. However, in cases of recurrence and post-irradiation, accurate identification of tumor remnants and a dural tail under bright light remains challenging. We aimed to perform real-time intraoperative visualization of the meningioma and dural tail using a delayed-window indocyanine green (ICG) technique with microscopy. Fifteen patients with intracranial meningioma received 0.5 mg/kg ICG a few hours before observation during the surgery. We used near-infrared (NIR) fluorescence to identify the tumor location. NIR fluorescence could visualize meningiomas in 12 out of 15 cases. Near-infrared visualization during the surgery ranged from 1 to 4 h after the administration of ICG. The mean signal-to-background ratio (SBR) of the intracranial meningioma in delayed-window ICG (DWIG) was 3.3 ± 2.6. The ratio of gadolinium-enhanced T1 tumor signal to the brain (T1BR) (2.5 ± 0.9) was significantly correlated with the tumor SBR (p = 0.016). K^trans, indicating blood–brain barrier permeability, was significantly correlated with tumor SBR (p < 0.0001) and T1BR (p = 0.013) on dynamic contrast-enhanced magnetic resonance imaging (MRI). DWIG demonstrated a sensitivity of 94%, specificity of 38%, positive predictive value (PPV) of 76%, and negative predictive value (NPV) of 75% for meningiomas. This is the first pilot study in which DWIG fluorescence-guided surgery was used to visualize meningioma and dural tail intraoperatively with microscopy. DWIG is comparable with second-window ICG in terms of mean SBR. Gadolinium-enhanced T1 tumor signal may predict NIR fluorescence of the intracranial meningioma. Blood–brain barrier permeability as shown by K^trans on dynamic contrast-enhanced MRI can contribute to gadolinium enhancement on MRI and to ICG retention and tumor fluorescence by NIR.

Background: Cerebral amyloid angiopathy-related inflammation (CAA-I) presents with slowly progressive nonspecific neurological symptoms, such as headache, cognitive function disorder, and seizures. Pathologically, the deposition of amyloid-β proteins at the cortical vascular wall is a characteristic and definitive finding. Differential diagnoses include infectious encephalitis, neurosarcoidosis, primary central nervous system lymphoma, and glioma. Here, we report a case of CAA-I showing acute progression, suggesting a glioma without enhancement, in which a radiological diagnosis was difficult using standard magnetic resonance imaging. Case Description: An 80-year-old woman was admitted due to transient abnormal behavior. Her initial imaging findings were similar to those of a glioma. She presented with rapid progression of the left hemiplegia and disturbance of consciousness for 6 days after admission and underwent emergent biopsy with a targeted small craniotomy under general anesthesia despite her old age. Intraoperative macroscopic findings followed by a pathological study revealed CAA-I as the definitive diagnosis. Steroid pulse therapy with methylprednisolone followed by oral prednisolone markedly improved both the clinical symptoms and imaging findings. Conclusion: Differential diagnosis between CAA-I and nonenhancing gliomas may be difficult using standard imaging studies in cases presenting with acute progression. A pathological diagnosis under minimally invasive small craniotomy may be an option, even for elderly patients.

BACKGROUND: We investigated the ability of magnetic resonance imaging (MRI) to distinguish primary central nervous system vasculitis (PCNSV) from glioblastoma to facilitate the development of an appropriate treatment for PCNSV. METHODS: We enrolled patients who were treated for PCNSV or glioblastoma at our center between January 2007 and August 2018. We compared the diagnoses of the 2 conditions by retrospectively reviewing patients' data for contrast-enhanced MRI, perfusion MRI, flow-sensitive black-blood (FSBB) imaging, and 1H-magnetic resonance spectroscopy (MRS). RESULTS: We evaluated 108 patients (6 PCNSV; 102 glioblastoma). We found a statistically significant correlation between diagnosis and the contrast pattern on MRI. Perivascular enhancement was observed in all cases of PCNSV as follows: ring-like, homogeneous, and irregular patterns were observed in 53 (60%), 18 (20%), and 17 (19%) cases of glioblastoma, respectively. We identified a statistically significant correlation between diagnosis and cerebral blood volume (CBV) in 3 patients with PCNSV who underwent perfusion MRI; and all had low CBVs. Among the 55 patients with glioblastoma who underwent perfusion MRI, low and high CBVs were detected in 3 and 52 patients, respectively. There was no significant correlation between diagnosis and FSBB findings. Evaluation of 1H-MRS data showed statistically significant differences between PCNSV and glioblastoma as functions of neuronal amino acid levels on long echo time MRS, with a slightly different amino acid profile, including glutamine + glutamate on short echo time MRS. CONCLUSIONS: Contrast-enhanced MRI, perfusion MRI, and quantitative analysis of 1H-MRS are valuable techniques for distinguishing PCNSV from glioblastoma before surgery.

Digital subtraction angiography (DSA) assesses the necessity of preoperative embolization in meningioma cases but entails complication risks. Previous studies evaluating meningiomas' angiographic vascularity using perfusion-weighted imaging (PWI) have performed subjective visual assessments, not managing to assess the need for preoperative embolization. We objectively assessed the angiographic stain of meningiomas and examined the usefulness of two parameters of dynamic susceptibility contrast (DSC)-PWI, normalized cerebral blood volume (nCBV) and cerebral blood flow (nCBF), in predicting vascularity and the necessity of preoperative embolization. We retrospectively examined 52 patients who underwent surgery for primary meningioma and preoperative DSA and DSC-PWI. We calculated the normalized luminance (nLum) of the tumor stain in DSA. In 29 meningioma cases with a single feeding artery, we determined the DSC-PWI parameter that correlated with meningioma angiographic vascularity and predicted the necessity of preoperative embolization. We also compared vascularity between meningiomas with single and multiple feeding arteries and between convexity and skull-base meningiomas. nCBF (cut off: 3.66, P = 0.03, area under the curve [AUC] = 0.80) alone could predict the necessity of preoperative embolization and was more significantly correlated with the nLum than nCBV (P = 0.08, AUC = 0.73). Vascularity did not differ between meningiomas with single and multiple feeding arteries; skull-base meningiomas were more vascularized than convexity meningiomas (P = 0.0027). Our objective, quantitative assessments revealed nCBF as the most suitable parameter for evaluating meningioma vascularity. Tumor vascularity assessment using nCBF values and CBF images may aid predicting the necessity of preoperative DSA.

Abstract Background: Although high dose-methotrexate therapy has been performed for primary central nervous system malignant lymphoma (PCNSL), R-MPV (rituximab, methotrexate (MTX), procarbazine and vincristine) therapy is currently the first line therapy for (PCNSL) in our hospital. This study examines the results of R-MPV therapy comparing with past treatment. Method/Subjects: Thirty-seven patients treated at our hospital from 2009 to 2020 were included. Overall survival time, progression free survival time, and toxicities were evaluated. Results: The average age of patients was 65.7 years. Patients included 21 males and 16 females. Thirty-six patients were diagnosed DLBCL by resected brain tumor tissues, and one was diagnosed DLBCL by vitreous biopsy. As initial treatment, rituximab±HD-MTX therapy (R±MTX group) was performed in 20 cases, HD-MTX therapy plus radiation (R±MTX+RT group) was performed in 12 cases, and RMPV therapy was performed in 5 cases (R-MPV group). Median OS of all cases was 69 months and median PFS was 38 months. Median OS was 69 months in R±MTX group and could not be calculated in R±MTX+RT, and R-MPV groups. Median PFS was 16 months and 56 months in R±MTX group and R±MTX+RT, respectively, and could not be calculated in the R-MPV group. Although the R-MPV group had a short follow-up period, the results were considered to be comparable to those of the R±MTX+RT group. On the other hand, grade 3/4 adverse events occurred in 50%, 25%, and 100%, respectively. Conclusion: R-MPV therapy may delay the timing of radiation and reduce the amount of radiation. On the other hand, the frequency of adverse events is high, and more strict management of treatment is required.

BACKGROUND: The extent of resection has been reported to be associated with overall survival in gliomas. The use of 5-aminolevulinic acid (5-ALA) has been recognized to increase the extent of tumor resection. OBJECTIVE: To evaluate what factors affect the intraoperative fluorescence after administration of 5-ALA in gliomas. METHODS: Correlation of intraoperative fluorescence and several clinical, radiographic, molecular biologic, and histopathologic characters was retrospectively evaluated in 104 patients (53 males and 51 females; mean age 54.2 yr) with gliomas at our institution. To clarify the mechanisms that mutant isocitrate dehydrogenase (IDH) affect the intraoperative fluorescence, in Vitro experiments using genetically engineered glioma cells harboring mutant IDH1 were performed. RESULTS: Intraoperative fluorescence was observed in 82 patients (78.8%). In addition to age, magnetic resonance imaging enhancement, World Health Organization grades, and MIB-1 index, the status of IDH was revealed to be correlated with intraoperative fluorescence. In Vitro assay revealed that mutant IDH indirectly reduced the amount of exogenous 5-ALA-derived protoporphyrinogen IX in glioma cells by increasing activity of ferrochelatase and heme oxygenase 1. CONCLUSION: Mutant IDH1/2-induced metabolite changes of exogenous 5-ALA were suggested to contribute to the lesser intraoperative fluorescence in gliomas with mutant IDH1/2 than in those without.

Seizures occurring after clipping of unruptured cerebral aneurysms have rarely been documented in the literature. The objective of this retrospective study is to clarify whether the frequency of early seizures, i.e., seizures occurring within 14 days of surgery, is influenced by patient- or aneurysm-specific characteristics. Data on 1,000 consecutive patients who underwent clipping of unruptured anterior circulation aneurysms were reviewed. They consisted of 387 men and 613 women with mean age of 59.8 ± 9.7 years. Fifty-one patients (5.1 %) developed early seizures. Interestingly, the frequency was similar to that occurring after clipping of unruptured posterior circulation aneurysms (n = 20, 5.0 %). Multivariate regression analysis revealed that younger age was correlated with early seizures (odds ratio (OR) 0.902; 95 % confidence interval (CI) 0.891-0.989). However, other variables, including aneurysm size and operation length, were not correlated. Although patients with history of epilepsy exhibited relatively high frequency of early seizures, the difference was not statistically significant. The frequency was unaffected by location or multiplicity of aneurysms. Thirty-one patients (61 %) developed seizures within 24 h of clipping. Regarding seizure types, 34 (67 %) developed generalized seizures and the other 17 (33 %) experienced partial seizures. Patients with generalized seizures were significantly more likely to harbor an iatrogenic brain lesion than those with partial seizures (47 vs. 18 %; OR 4.148; 95 % CI 1.005-17.113). Among 40 patients with follow-up period >12 months, seizures were temporary without recurrence in 38 (95 %). Although early seizures are mostly benign, a small possibility of them becoming a permanent morbidity needs to be explained to patients undergoing elective clipping.