TB-8 Genetic and molecular properties of long-term proliferating tumorsphere -forming glioma derived cells

Long-term proliferating tumorsphere-forming glioma derived cells (LTP-TS-GDCs) and patient derived xenografts (PDXs) are essential tools for translational research for glioma. However, only small subsets of glioma samples are established as LTP-TS and/or PDXs and little is known about the genetics and molecular properties of LTP-TS -forming GDCs and PDX. In this study, we aim to analyze the characteristics of LTP-TS -forming GDCs and PDXs. We tried primary sphere cultures from 56 glioma patient-derived samples and established 11 LTP-TS-GDCs out of 45 glioblastoma samples and no long-term sphere culture was isolated from grade3 and grade 2 gliomas. LTP-TS-GDCs had self-renewal ability and possessed certain multipotency. However, they significantly less expressed SOX1 FOXG1 and TUBB3, whereas they expressed LGALS1 and EN1 significantly higher than normal neural stem/progenitor cells. In addition, we found that LTP-TS-GDCs shared the same genetic profiles with original patients’ tumors. Furthermore, we investigated the genetic differences between the glioma tissues which were successfully established as LTP-TS-GDCs and those which were not. We found that glioma tissues with TERT promotor mutations and triple copy number alteration (CNA) [EGFR, CDKN2A, and PTEN loci] are significantly established as LTP-TS-GDCs. Lastly, we next investigated in vivo characteristics of glioma PDXs. We have injected glioma PDXs lines into immunodeficient mice brains and histopathologically analyzed the characteristics of xenografts. Each xenograft well recapitulated histological features of original patients’ tumors and tumor cells remarkably invade through subventricular zone. In conclusion, each LTP-TS-GDCs and PDXs had various gene expression profiles, reflecting intratumoral and interpatient heterogeneities of glioma. In addition, TERT promotor mutations and triple CNA significantly correlated with success rate of LTP-TS-GDCs. These findings will be of use and advance the preclinical and translational researches of glioma.

TMOD-05. GENETIC AND MOLECULAR PROPERTIES OF LONG-TERM PROLIFERATING TUMORSPHERE -FORMING GLIOMA DERIVED CELLS

Long-term proliferating tumorsphere (LTP-TS)-forming glioma derived cells (GDCs) and patient derived xenografts (PDXs) are essential tools for translational research for glioma. However, only small subsets of glioma samples are established as LTP-TS and/or PDXs and little is known about the genetics and molecular properties of LTP-TS -forming GDCs and PDX. In this study, we aim to analyze the characteristics of LTP-TS -forming GDCs and PDXs. We tried primary sphere cultures from 56 glioma patient-derived samples and established 14 LTP-TS -forming GDCs out of 48 glioblastoma samples and no long-term sphere culture was isolated from grade3 and grade 2 gliomas. LTP-TS -forming GDCs had self-renewal ability and possessed certain multipotency. However, they significantly less expressed SOX1 FOXG1 and TUBB3, whereas they expressed LGALS1 significantly higher than normal neural stem/progenitor cells. In addition, we found that LTP-TS -forming GDCs shared the same genetic profiles with original patients’ tumors. Furthermore, we investigated the genetic differences between the glioma tissues which were successfully established as LTP-TS -forming GDCs and those which were not. We found that glioma tissues with TERT promotor mutations and triple CNA (EGFR, CDKN2A, and PTEN loci) are significantly established as LTP-TS -forming GDCs. Lastly, we next investigated in vivo characteristics of glioma PDXs. We have injected glioma PDXs lines into immunodeficient mice and histopathologically analyzed the characteristics of xenografts. Each xenograft well recapitulated histological features of original patients’ tumors and tumor cells remarkably invade through subventricular zone. In conclusion, each LTP-TS -forming GDCs and PDXs had various gene expression profiles, reflecting intratumoral and interpatient heterogeneities of glioma. In addition, TERT promotor mutations and triple CNA significantly correlated with success rate of LTP-TS -forming GDCs. These findings will be of use and advance the preclinical and translational researches of glioma.

Specific Oscillatory Power Changes and Their Efficacy for Determining Laterality in Mesial Temporal Lobe Epilepsy: A Magnetoencephalographic Study

Appropriate determination of the epileptic focus and its laterality are important for the diagnosis of mesial temporal lobe epilepsy (MTLE). The aims of this study are to establish a specific oscillatory distribution and laterality of the oscillatory power in unilateral MTLE with frequency analysis of magnetoencephalography (MEG), and to confirm their potential to carry significant information for determining lateralization of the epileptic focus. Thirty-five patients with MTLE [left (LtMTLE), 16; right (RtMTLE), 19] and 102 healthy control volunteers (CTR) were enrolled. Cortical oscillatory powers were compared among the groups by contrasting the source images using a one-way ANOVA model for each frequency band. Further, to compare the lateralization of regional oscillatory powers between LtMTLEs and RtMTLEs, the laterality index (LI) was calculated for four brain regions (frontal, temporal, parietal, and occipital) in each frequency band, which were compared between patient groups (LtMTLE, RtMTLE, and CTR), and used for machine learning prediction of the groups with support vector machine (SVM) with linear kernel function. Significant oscillatory power differences between MTLE and CTR were found in certain areas. In the theta to high-frequency oscillation bands, there were marked increases in the parietal lobe, especially on the left side, in LtMTLE. In the theta, alpha, and high-gamma bands, there were marked increases in the parietal lobe, especially on the right side in RtMTLE. Compared with CTR, LIs were significantly higher in 24/28 regions in LtMTLE, but lower in 4/28 regions and higher in 10/28 regions in RtMTLE. LI at the temporal lobe in the theta band was significantly higher in LtMTLE and significantly lower in RtMTLE. Comparing LtMTLE and RtMTLE, there were significant LI differences in most regions and frequencies (21/28 regions). In all frequency bands, there were significant differences between LtMTLE and RtMTLE in the temporal and parietal lobes. The leave-one-out cross-validation of the linear-SVM showed the classification accuracy to be over 91%, where the model had high specificity over 96% and mild sensitivity ~68–75%. Using MEG frequency analysis, the characteristics of the oscillatory power distribution in the MTLE were demonstrated. Compared with CTR, LIs shifted to the side of the epileptic focus in the temporal lobe in the theta band. The machine learning approach also confirmed that LIs have significant predictive ability in the lateralization of the epileptic focus. These results provide useful additional information for determining the laterality of the focus.

Diagnostic Performance of [11C]Methionine Positron Emission Tomography in Newly Diagnosed and Untreated Glioma Based on the Revised World Health Organization 2016 Classification

BACKGROUND

The relationship between uptake of amino acid tracer with positron emission tomography (PET) and glioma subtypes/gene status is still unclear.

OBJECTIVE

To assess the relationship between uptake of [¹¹C]methionine using PET and pathology, IDH (isocitrate dehydrogenase) mutation, 1p/19q codeletion, and TERT (telomerase reverse transcriptase) promoter status in gliomas.

METHODS

The participants were 68 patients with newly diagnosed and untreated glioma who underwent surgical excision and preoperative [¹¹C]methionine PET examination at Osaka City University Hospital between July 2011 and March 2018. Clinical and imaging studies were reviewed retrospectively based on the medical records at our institution.

RESULTS

The mean lesion/contralateral normal brain tissue (L/N) ratio of diffuse astrocytomas was significantly lower than that of anaplastic astrocytomas (P = 0.00155), glioblastoma (P < 0.001), and oligodendrogliomas (P = 0.0157). The mean L/N ratio of IDH mutant gliomas was significantly lower than that of IDH wild-type gliomas (median 1.75 vs. 2.61; P = 0.00162). A mean L/N ratio of 2.05 provided the best sensitivity and specificity for distinguishing between IDH mutant and IDH wild-type gliomas (69.2% and 76.2%, respectively). The mean L/N ratio of TERT promoter mutant gliomas was significantly higher than that of TERT promoter wild-type gliomas (P = 0.0147). Multiple regression analysis showed that pathologic diagnosis was the only influential factor on L/N ratio.

CONCLUSIONS

Distinguishing glioma subtypes based on the revised 2016 World Health Organization classification of the central nervous system tumors on the basis of [¹¹C]methionine PET alone seems to be difficult. However, [¹¹C]methionine PET might be useful for predicting the IDH mutation status in newly diagnosed and untreated gliomas noninvasively before tumor resection.

NIMG-29. DEVELOPING AUTOMATIC SEGMENTATION METHOD FOR BRAIN TUMOR MR IMAGES THAT CAN BE USED AT MULTIPLE FACILITIES

BACKGROUND

Manual segmentation of brain tumor images from a large volume of MR images generated in clinical routines is difficult and time-consuming. Hence, it is imperative to develop a machine learning model for automated segmentation of brain tumor images.

PURPOSE

Machine learning models for automated MR image segmentation of gliomas may be useful. However, the image differences among facilities cause performance degradation and impede successful automatic segmentation. In this study, we proposed a method to solve this issue.

METHODS

We used the data from the Multimodal Brain Tumor Image Segmentation Benchmark (BraTS) and the Japanese cohort (JC) datasets collected from 10 facilities. Three models for tumor segmentation were developed. The BraTS model was trained on the BraTS dataset, and the JC model was trained on the JC dataset; whereas, the Fine-tuning model was a fine-tuned BraTS model using the JC dataset.

RESULTS

MR images of 544 patients were obtained for the JC dataset. Half of the JC dataset was used for independent testing. The Dice coefficient score of the JC model for the JC dataset was 0.779± 0.137, whereas that of the BraTS model was remarkably lower (0.717 ± 0.207). The mean of the Fine-tuning models for the JC dataset was 0.769 ± 0.138. There was a significant difference between the BraTS and JC models (P &lt; 0.0001) and the BraTS and Fine-tuning models (P = 0.002); however, no significant difference was observed between the JC and Fine-tuning models (P = 0.673).

CONCLUSIONS

Application of the BraTS model to heterogeneous datasets can significantly reduce its performance; however, fine-tuning can solve this issue. Since our fine-tuning method only requires less than 20 cases, this methodology is particularly useful for a facility where there are a few glioma cases.

Molecular characteristics and clinical outcomes of elderly patients with IDH-wildtype glioblastomas: comparative study of older and younger cases in Kansai Network cohort

Aging is a known negative prognostic factor in glioblastomas (GBM). Whether particular genetic backgrounds are a factor in poor outcomes of elderly patients with GBM warrants investigation. We aim to elucidate any differences between older and younger adult patients with IDH-wildtype GBM regarding both molecular characteristics and clinical outcomes. We collected adult cases diagnosed with IDH-wildtype GBM from the Kansai Network. Clinical and pathological characteristics were analyzed retrospectively and compared between older (≥ 70 years) and younger (≤ 50 years) cases. Included were 92 older vs. 33 younger cases. The older group included more patients with preoperative Karnofsky performance status score < 70 and had a shorter survival time than the younger group. MGMT promoter was methylated more frequently in the older group. TERT promoter mutation was more common in the older group. There were significant differences in DNA copy-number alteration profiles between age groups in PTEN deletion and CDK4 amplification/gain. In the older group, no molecular markers were identified, but surgical resection was an independent prognostic factor. Age-specific survival difference was significant in the MGMT methylated and TERT wildtype subgroup. Elderly patients have several potential factors in poor prognosis of glioblastomas. Varying molecular profiles may explain differing rates of survival between generations.

[A Case of Primary Central Nervous System Lymphomatoid Granulomatosis that was Completely Ameliorated by Corticosteroid Treatment]

Lymphomatoid granulomatosis (LYG) is an angiocentric, angiodestructive lymphoreticular proliferative disease that usually affects the lungs but it has been speculated to also effect the central nervous system (CNS). However, unique primary LYG of the CNS has rarely been reported in the literature. Herein, we describe a clinical case of a 37-year-old female patient with grade 1 primary CNS-LYG having a good prognosis owing to corticosteroid treatment. The aforesaid patient, presented with a headache and left leg weakness with no evidence of a systemic disease. MRI revealed multiple small enhancing nodules in the right hemisphere with diffuse high-intensity lesions on T₂/ FLAIR image. A brain biopsy showed lymphohistiocytic cells with blood vessels infiltrated with CD3+ and CD20+. The Epstein-Barr virus encoded small RNA-ISH test was negative. Based on the above findings, grade 1 primary CNS-LYG was diagnosed. Following the administration of oral corticosteroids, a systemic high-dose corticosteroid therapy was administrated. Complete remission was achieved and maintained for 24 months following treatment. Grade 1 primary CNS-LYG is a rare disease that is not apparently associated with the Epstein-Barr virus (EBV) and possibly yields much better prognosis than the frequently EBV-positive systemic LYG with CNS localization. (Received November 5, 2019; Accepted November 20, 2019; Published February 1, 2020).

Prediction of IDH and TERT promoter mutations in low-grade glioma from magnetic resonance images using a convolutional neural network

Identification of genotypes is crucial for treatment of glioma. Here, we developed a method to predict tumor genotypes using a pretrained convolutional neural network (CNN) from magnetic resonance (MR) images and compared the accuracy to that of a diagnosis based on conventional radiomic features and patient age. Multisite preoperative MR images of 164 patients with grade II/III glioma were grouped by IDH and TERT promoter (pTERT) mutations as follows: (1) IDH wild type, (2) IDH and pTERT co-mutations, (3) IDH mutant and pTERT wild type. We applied a CNN (AlexNet) to four types of MR sequence and obtained the CNN texture features to classify the groups with a linear support vector machine. The classification was also performed using conventional radiomic features and/or patient age. Using all features, we succeeded in classifying patients with an accuracy of 63.1%, which was significantly higher than the accuracy obtained from using either the radiomic features or patient age alone. In particular, prediction of the pTERT mutation was significantly improved by the CNN texture features. In conclusion, the pretrained CNN texture features capture the information of IDH and TERT genotypes in grade II/III gliomas better than the conventional radiomic features.

ACT-10 TREATMENT FOR GLIOBLASTOMA RECURRED AFTER CONCOMITANT CHEMORADIATION THERAPY WITH TEMOZOLOMIDE AND THEIR PROGNOSIS

There are few data about treatment for glioblastoma recurred after concomitant chemoradiation therapy with temozolomide (TMZ). We retrospectively examined treatment and prognosis of recurred glioblastoma patients who registered Kansai molecular diagnosis network for central nervous system tumors, and whose clinical information were available. One hundred and fifty-seven patients that were clinically diagnosed as recurrence between November 2007 and April 2019 were included. Their median age at primary diagnosis was 52 years old and median KPS was 80%. Proportion of methylated MGMT promoter was 43.3% (65 patients), and mutated IDH was 5.4% (8 patients). Median overall survival after recurrence (mSAR) was 8.2 months. One hundred and sixteen patients (73.9%) were received any anticancer treatment and their mSAR was 10.5m. Combination of TMZ and bevacizumab (Bev) were most frequently used for 33 patients, followed by Bev monotherapy for 17 patients, surgery + TMZ + Bev for 15 patients, surgery + TMZ for 12 patients, and TMZ monotherapy for ten. Their mSAR were 8.0m, 7.5m, 10.5m, 13.0m, and 8.0m, respectively. Using univariate analysis, MGMT promoter methylation (p=0.0007), TMZ (p=0.00933), surgery (p=0.0126), re-radiation (p=0.0367), and surgery+TMZ+Bev (p=0.0493) significantly affected prognosis. By multivariate analysis, MGMT promoter methylation, TMZ, and re-radiation were statistically significant (p=0.000138, 0.00161, 0.00403, respectively). These data showed that relatively young patients with good performance status would receive anti-cancer treatment beyond progression and MGMT promoter methylation might be one of prognostic factor for longer survival. In this cohort, re-radiation was performed for few patients and nitrosourea such as nimustine was almost not used. Further study would be needed whether these treatments have any positive effect or not.

ACT-13 RESPONSE TO SEIZURE AND TUMOR-PROGRESSION BY TREATMENT WITH PERAMPANEL IN PATIENTS WITH GLIOMAS

BACKGROUND

Increased extracellular glutamate level activates AMPA type glutamate receptors (AMPA-receptor) and induces seizures. Antagonistic activation of AMPA-receptors inhibits epilepsy and glioma progression in vivo and in vitro studies.

PATIENTS AND METHODS

(1) We tested perampanel (PER), an AMPA-receptor antagonist, in fifteen glioma patients with uncontrolled epilepsy. Seizure response, PER concentration, and tumor volume were assessed. (2) We tested PER in thirteen glioma patients (gr 2- 3 cases, gr 3- 4 cases, and gr 4- 4cases) after the initial treatment of surgery and RT (and CT).

RESULTS

(1) An objective seizure response was observed in 13 analyzed patients (100%) with 8 cases (62%) of seizure-freedom. Median plasma concentration of PER was 232 ng/ml in patients with 4mg/day PER and 518 ng/ml in patients with 8mg/day PER. High intensity lesions of MRI-FLAIR images were assessed volumetrically to analyze the tumor size. The volume reduction was detected during the 6 months period in correlation with the plasma PER levels. (2) All the 13 cases treated with PER after the initial treatment was seizure free. Two cases of gr 4 were died at 18 and 20 months after the surgical treatment. Other 11 cases are survival-free.

CONCLUSION

PER treatment was effective in uncontrolled epilepsy with gliomas. MRI images showed the inhibition of tumor-progression. PER may effective for the inhibition of tumor progression.

TB-08 PATIENT DERIVED XENOGRAFT’S BIOBANK FROM KANSAI MOLECULAR DIAGNOSIS NETWORK FOR CENTRAL NERVOUS SYSTEM TUMORS

Patient-derived xenografts (PDXs) are essential tools for translational research for brain tumors. However, it is sometimes difficult for each institution to establish PDXs because it needs experiences and techniques and it also takes a lot of works to establish them. Thus we aim to establish patient derived xenograft’s biobank among institutions of Kansai Molecular Diagnosis Network for Central Nervous System (CNS) Tumors, Osaka, Japan. We have already began sharing two anaplastic astrocytoma PDXs, twelve glioblastoma IDH wild type PDXs, two medulloblastoma Shh subgroup PDXs, one atypical teratoid/rhabdoid tumor (AT/RT) PDX, and three metastatic brain tumor PDXs. Furthermore these PDXs can also be cultured in vitro, except 2 medulloblastoma SHH subgroup PDXs, 1 AT/RT PDX. However, we have not yet established any PDXs from low grade glioma, ependymoma, primary central nervous system lymphoma (PCNSL), diffuse intrinsic pontine glioma (DIPG).

We began sharing these PDXs among the institutions of Kansai Molecular Diagnosis Network for CNS Tumors, Osaka, Japan. However, further improvement is necessary to succeed in establishing PDX from low grade glioma, PCSNL, DIPG, etc. and get enough number of PDXs so we can share PDXs from almost all of the brain tumors.

TMOD-01. CHARACTERIZATION OF PATIENT-DERIVED PRIMARY CELL LINES AND XENOGRAFTS FOR GLIOBLASTOMA

Patient-derived primary cell culture and xenograft are essential tools for translational research for glioblastoma. However, characteristics of each patient derived cell line and xenograft is not extensively studied. In this study, we aim to analyze the characteristics of our glioblastoma patient-derived cell lines and xenografts based on cell surface markers and their differentiation patterns. We have established 20 glioblastoma primary cell culture lines by serum free medium containing EGF and bFGF and found that primary cell culture lines could be classified based on the expression of CD133 and CD44. Four cell lines had high expression of both CD133 and CD44. Eleven cell lines had high expression of only CD44, three cell lines had high expression of only CD133, two cell lines had low expression of both CD133 and CD44. In addition when we induce differentiation, these cell lines showed differentiation to both glial and neuronal differentiation, but differentiation patterns were different depending on each cell line. Four cell lines showed predominant neuronal differentiation and others showed predominant glial differentiation. We next investigated in vivo characteristics of glioblastoma patient derived xenografts from these established cell lines. We have injected these cell lines into NOD/Shi-scid IL2Rγ KO mouse and histopathologically analyzed characteristics of xenografts. Each xenograft well recapitulated histological features of original patients’ tumors and tumor cells remarkably invade through subventricular zone. These results suggest that glioblastoma patient derived primary cell lines and xenografts have different characteristics of cell surface marker expressions and differentiation patterns, thus can classify these cell lines depending on cell surface marker expressions and differentiation patterns. Further analysis is needed to examine the biological importance of the differences in cell surface marker expressions and differentiation patterns.

Distribution differences in prognostic copy number alteration profiles in IDH-wild-type glioblastoma cause survival discrepancies across cohorts

The diagnosis and prognostication of glioblastoma (GBM) remain to be solely dependent on histopathological findings and few molecular markers, despite the clinical heterogeneity in this entity. To address this issue, we investigated the prognostic impact of copy number alterations (CNAs) using two population-based IDH-wild-type GBM cohorts: an original Japanese cohort and a dataset from The Cancer Genome Atlas (TCGA). The molecular disproportions between these cohorts were dissected in light of cohort differences in GBM. The Japanese cohort was collected from cases registered in Kansai Molecular Diagnosis Network for CNS tumors (KNBTG). The somatic landscape around CNAs was analyzed for 212 KNBTG cases and 359 TCGA cases. Next, the clinical impacts of CNA profiles were investigated for 140 KNBTG cases and 152 TCGA cases treated by standard adjuvant therapy using temozolomide-based chemoradiation. The comparative profiling indicated unequal distribution of specific CNAs such as EGFR, CDKN2A, and PTEN among the two cohorts. Especially, the triple overlap CNAs in these loci (triple CNA) were much higher in frequency in TCGA (70.5%) than KNBTG (24.3%), and its prognostic impact was independently validated in both cohorts. The KNBTG cohort significantly showed better prognosis than the TCGA cohort (median overall survival 19.3 vs 15.6 months). This survival difference between the two cohorts completely resolved after subclassifying all cases according to the triple CNA status. The prognostic significance of triple CNA was identified in IDH-wild-type GBM. Distribution difference in prognostic CNA profiles potentially could cause survival differences across cohorts in clinical studies.

Significance of molecular classification of ependymomas: C11orf95-RELA fusion-negative supratentorial ependymomas are a heterogeneous group of tumors

Extensive molecular analyses of ependymal tumors have revealed that supratentorial and posterior fossa ependymomas have distinct molecular profiles and are likely to be different diseases. The presence of C11orf95-RELA fusion genes in a subset of supratentorial ependymomas (ST-EPN) indicated the existence of molecular subgroups. However, the pathogenesis of RELA fusion-negative ependymomas remains elusive. To investigate the molecular pathogenesis of these tumors and validate the molecular classification of ependymal tumors, we conducted thorough molecular analyses of 113 locally diagnosed ependymal tumors from 107 patients in the Japan Pediatric Molecular Neuro-Oncology Group. All tumors were histopathologically reviewed and 12 tumors were re-classified as non-ependymomas. A combination of RT-PCR, FISH, and RNA sequencing identified RELA fusion in 19 of 29 histologically verified ST-EPN cases, whereas another case was diagnosed as ependymoma RELA fusion-positive via the methylation classifier (68.9%). Among the 9 RELA fusion-negative ST-EPN cases, either the YAP1 fusion, BCOR tandem duplication, EP300-BCORL1 fusion, or FOXO1-STK24 fusion was detected in single cases. Methylation classification did not identify a consistent molecular class within this group. Genome-wide methylation profiling successfully sub-classified posterior fossa ependymoma (PF-EPN) into PF-EPN-A (PFA) and PF-EPN-B (PFB). A multivariate analysis using Cox regression confirmed that PFA was the sole molecular marker which was independently associated with patient survival. A clinically applicable pyrosequencing assay was developed to determine the PFB subgroup with 100% specificity using the methylation status of 3 genes, CRIP1, DRD4 and LBX2. Our results emphasized the significance of molecular classification in the diagnosis of ependymomas. RELA fusion-negative ST-EPN appear to be a heterogeneous group of tumors that do not fall into any of the existing molecular subgroups and are unlikely to form a single category.

Lesion location implemented magnetic resonance imaging radiomics for predicting IDH and TERT promoter mutations in grade II/III gliomas

Molecular biological characterization of tumors has become a pivotal procedure for glioma patient care. The aim of this study is to build conventional MRI-based radiomics model to predict genetic alterations within grade II/III gliomas attempting to implement lesion location information in the model to improve diagnostic accuracy. One-hundred and ninety-nine grade II/III gliomas patients were enrolled. Three molecular subtypes were identified: IDH1/2-mutant, IDH1/2-mutant with TERT promoter mutation, and IDH-wild type. A total of 109 radiomics features from 169 MRI datasets and location information from 199 datasets were extracted. Prediction modeling for genetic alteration was trained via LASSO regression for 111 datasets and validated by the remaining 58 datasets. IDH mutation was detected with an accuracy of 0.82 for the training set and 0.83 for the validation set without lesion location information. Diagnostic accuracy improved to 0.85 for the training set and 0.87 for the validation set when lesion location information was implemented. Diagnostic accuracy for predicting 3 molecular subtypes of grade II/III gliomas was 0.74 for the training set and 0.56 for the validation set with lesion location information implemented. Conventional MRI-based radiomics is one of the most promising strategies that may lead to a non-invasive diagnostic technique for molecular characterization of grade II/III gliomas.

Characteristics and outcomes of elderly patients with diffuse gliomas: a multi-institutional cohort study by Kansai Molecular Diagnosis Network for CNS Tumors

Introduction

This study investigates the current state of clinical practice and molecular analysis for elderly patients with diffuse gliomas and aims to elucidate treatment outcomes and prognostic factors of patients with glioblastomas.

Methods

We collected elderly cases (≥ 70 years) diagnosed with primary diffuse gliomas and enrolled in Kansai Molecular Diagnosis Network for CNS Tumors. Clinical and pathological characteristics were analyzed retrospectively. Various factors were evaluated in univariate and multivariate models to examine their effects on overall survival.

Results

Included in the study were 140 elderly patients (WHO grade II: 7, III: 19, IV: 114), median age was 75 years. Sixty-seven patients (47.9%) had preoperative Karnofsky Performance Status score of ≥ 80. All patients underwent resection (gross-total: 20.0%, subtotal: 14.3%, partial: 39.3%, biopsy: 26.4%). Ninety-six of the patients (68.6%) received adjuvant treatment consisting of radiotherapy (RT) with temozolomide (TMZ). Seventy-eight of the patients (75.0%) received radiation dose of ≥ 50 Gy. MGMT promoter was methylated in 68 tumors (48.6%), IDH1/2 was wild-type in 129 tumors (92.1%), and TERT promoter was mutated in 78 of 128 tumors (60.9%). Median progression-free and overall survival of grade IV cases was 8.2 and 13.6 months, respectively. Higher age (≥ 80 years) and TERT promoter mutated were associated with shorter survival. Resection and adjuvant RT + TMZ were identified as independent factors for good prognosis.

Conclusions

This community-based study reveals characteristics and outcomes of elderly glioma patients in a real-world setting. Elderly patients have several potential factors for poor prognosis, but resection followed by RT + TMZ could lengthen duration of survival.

Electronic supplementary material

The online version of this article (10.1007/s11060-018-2957-7) contains supplementary material, which is available to authorized users.

Diagnostic Performance and Safety of Positron Emission Tomography Using 18F-Fluciclovine in Patients with Clinically Suspected High- or Low-grade Gliomas: A Multicenter Phase IIb Trial

OBJECTIVES

The study objective was to assess the diagnostic performance of positron emission tomography (PET) for gliomas using the novel tracer 18F-fluciclovine (anti-[18F]FACBC) and to evaluate the safety of this tracer in patients with clinically suspected gliomas.

METHODS

Anti-[18F]FACBC was administered to 40 patients with clinically suspected high- or low-grade gliomas, followed by PET imaging. T1-weighted, contrast-enhanced T1-weighted, and fluid-attenuated inversion recovery (or T2-weighted) magnetic resonance imaging (MRI) scans were obtained to plan for the tissue collection. Tissues were collected from either "areas visualized using anti-[18F]FACBC PET imaging but not using contrast-enhanced T1-weighted imaging" or "areas visualized using both anti-[18F]FACBC-PET imaging and contrast-enhanced T1-weighted imaging" and were histopathologically examined to assess the diagnostic accuracy of anti-[18F]FACBC-PET for gliomas.

RESULTS

The positive predictive value of anti-[18F]FACBC-PET imaging for glioma in areas visualized using anti-[18F]FACBC-PET imaging, but not visualized using contrast-enhanced T1-weighted images, was 100.0% (26/26), and the value in areas visualized using both contrast-enhanced T1-weighted imaging and anti-[18F]FACBC-PET imaging was 87.5% (7/8). Twelve adverse events occurred in 7 (17.5%) of the 40 patients who received anti-[18F]FACBC. Five events in five patients were considered to be adverse drug reactions; however, none of the events were serious, and all except one resolved spontaneously without treatment.

CONCLUSION

This Phase IIb trial showed that anti-[18F]FACBC-PET imaging was effective for the detection of gliomas in areas not visualized using contrast-enhanced T1-weighted MRI and the tracer was well tolerated.

MEG Frequency Analysis Depicts the Impaired Neurophysiological Condition of Ischemic Brain

PURPOSE

Quantitative imaging of neuromagnetic fields based on automated region of interest (ROI) setting was analyzed to determine the characteristics of cerebral neural activity in ischemic areas.

METHODS

Magnetoencephalography (MEG) was used to evaluate spontaneous neuromagnetic fields in the ischemic areas of 37 patients with unilateral internal carotid artery (ICA) occlusive disease. Voxel-based time-averaged intensity of slow waves was obtained in two frequency bands (0.3-4 Hz and 4-8 Hz) using standardized low-resolution brain electromagnetic tomography (sLORETA) modified for a quantifiable method (sLORETA-qm). ROIs were automatically applied to the anterior cerebral artery (ACA), anterior middle cerebral artery (MCAa), posterior middle cerebral artery (MCAp), and posterior cerebral artery (PCA) using statistical parametric mapping (SPM). Positron emission tomography with 15O-gas inhalation (15O-PET) was also performed to evaluate cerebral blood flow (CBF) and oxygen extraction fraction (OEF). Statistical analyses were performed using laterality index of MEG and 15O-PET in each ROI with respect to distribution and intensity.

RESULTS

MEG revealed statistically significant laterality in affected MCA regions, including 4-8 Hz waves in MCAa, and 0.3-4 Hz and 4-8 Hz waves in MCAp (95% confidence interval: 0.020-0.190, 0.030-0.207, and 0.034-0.213), respectively. We found that 0.3-4 Hz waves in MCAp were highly correlated with CBF in MCAa and MCAp (r = 0.74, r = 0.68, respectively), whereas 4-8 Hz waves were moderately correlated with CBF in both the MCAa and MCAp (r = 0.60, r = 0.63, respectively). We also found that 4-8 Hz waves in MCAp were statistically significant for misery perfusion identified on 15O-PET (p<0.05).

CONCLUSIONS

Quantitatively imaged spontaneous neuromagnetic fields using the automated ROI setting enabled clear depiction of cerebral ischemic areas. Frequency analysis may reveal unique neural activity that is distributed in the impaired vascular metabolic territory, in which the cerebral infarction has not yet been completed.

A combination of TERT promoter mutation and MGMT methylation status predicts clinically relevant subgroups of newly diagnosed glioblastomas

The prognostic impact of TERT mutations has been controversial in IDH-wild tumors, particularly in glioblastomas (GBM). The controversy may be attributable to presence of potential confounding factors such as MGMT methylation status or patients' treatment. This study aimed to evaluate the impact of TERT status on patient outcome in association with various factors in a large series of adult diffuse gliomas. We analyzed a total of 951 adult diffuse gliomas from two cohorts (Cohort 1, n = 758; Cohort 2, n = 193) for IDH1/2, 1p/19q, and TERT promoter status. The combined IDH/TERT classification divided Cohort 1 into four molecular groups with distinct outcomes. The overall survival (OS) was the shortest in IDH wild-type/TERT mutated groups, which mostly consisted of GBMs (P < 0.0001). To investigate the association between TERT mutations and MGMT methylation on survival of patients with GBM, samples from a combined cohort of 453 IDH-wild-type GBM cases treated with radiation and temozolomide were analyzed. A multivariate Cox regression model revealed that the interaction between TERT and MGMT was significant for OS (P = 0.0064). Compared with TERT mutant-MGMT unmethylated GBMs, the hazard ratio (HR) for OS incorporating the interaction was the lowest in the TERT mutant-MGMT methylated GBM (HR, 0.266), followed by the TERT wild-type-MGMT methylated (HR, 0.317) and the TERT wild-type-MGMT unmethylated GBMs (HR, 0.542). Thus, patients with TERT mutant-MGMT unmethylated GBM have the poorest prognosis. Our findings suggest that a combination of IDH, TERT, and MGMT refines the classification of grade II-IV diffuse gliomas.

Glioblastoma in long-term survivors of acute lymphoblastic leukemia: Report of two cases

Acute lymphoblastic leukemia (ALL) is the most common form of cancer in children. Second neoplasms as late effects of therapy for ALL have been recognized as a significant clinical issue given the increasing number of long-term survivors of ALL, because they can be the cause of death in such cases. In contrast, glioblastoma (GBM) is the most common primary brain tumor in adults. It is a malignant brain tumor that most often occurs in elderly patients, and GBM in young adults or adolescents appears to be rare. Here, we describe our experience of two cases of GBM in young long-term survivors of ALL, and emphasize the necessity of careful follow up of patients treated for ALL for the potential occurrence of central nervous system second neoplasms, especially when the patients have previously undergone cranial radiotherapy.

Anatomic Understanding of Vertical Hemispherotomy With Cadaveric Brains and Intraoperative Photographs

BACKGROUND

Vertical hemispherotomy is performed in hemispheric epilepsy to disconnect commissural fibers, projecting fibers, and limbic system from the affected side of the brain with minimal parenchyma removal. However, anatomic understanding of this surgery is generally difficult.

OBJECTIVE

To present the vertical hemispherotomy procedures using cadaveric brains and intraoperative photographs.

METHODS

Two formalin-fixed adult cadaveric brains were used to demonstrate vertical hemispherotomy. Intraoperative photographs were taken of a 19-year-old man with intractable epilepsy due to head trauma in infancy.

RESULTS

After coronal skin incision along the coronal suture, bifrontal craniotomy and a C-shaped dural incision from lateral to medial to the midline are performed. The interhemispheric fissure is dissected from anterior to posterior. Interhemispheric total corpus callosotomy is performed to disconnect commissural fibers. Corticotomy on the cingulate gyrus is performed to approach the lateral ventricle. The lateral border of the thalamus is cut from posterior to anterior until exposing the inferior horn of the lateral ventricle and hippocampal head to disconnect projecting fibers. At the anteromedial side of the hippocampus, the inferior part of the amygdala and uncal gyrus is removed, exposing the basal cistern to disconnect the hippocampus and amygdala. The posterior column of the fornix at the trigone of the lateral ventricle is resected to disconnect the limbic system. Projecting fibers from the anterior frontal lobe are disconnected.

CONCLUSION

A step-by-step procedure using cadaveric brains and intraoperative photographs provide a better anatomic understanding of vertical hemispherotomy.

A prospective, multicentre, single-arm clinical trial of bevacizumab for patients with surgically untreatable, symptomatic brain radiation necrosis†

Background

Brain radiation necrosis (BRN) can be a complication of radiotherapy for primary and secondary brain tumors, as well as head and neck tumors. Since vascular endothelial growth factor (VEGF) is also a vascular permeability factor in the brain, bevacizumab, a humanized antibody that inhibits VEGF, would be expected to reduce perilesional edema that often accompanies BRN.

Methods

Patients with surgically untreatable, symptomatic BRN refractory to conventional medical treatments (eg, corticosteroid, anticoagulants, or hyperbaric oxygen therapy) were enrolled. We judged that a major cause of perilesional edema with a lesion-to-normal brain ratio ≤1.8 on ¹¹C-methionine or ≤2.5 on ¹⁸F-boronophenylalanine PET was BRN, not tumor recurrence, and 6 cycles of biweekly bevacizumab (5 mg/kg) were administered. The primary endpoint was a ≥30% reduction from the patients' registration for perilesional edema continuing for ≥1 month.

Results

Of the 41 patients enrolled, 38 were fully eligible for the response assessment. The primary endpoint was achieved in 30 of the 38 (78.9%) patients at 3.0 months (median) after enrollment. Sixteen patients (42.1%) experienced improvement of their Karnofsy Performance Score. Corticosteroid use could be reduced in 29 patients (76.3%). Adverse events at grade ≥3 occurred in 10 patients (24.4%).

Conclusions

Bevacizumab treatment offers certain clinical benefits for patients with surgically untreatable, symptomatic BRN. The determination of BRN using amino-acid PET, not biopsy, is adequate and less invasive for determining eligibility to receive bevacizumab.

Embryonal tumor with abundant neuropil and true rosettes in the brainstem: case report

Embryonal tumor with abundant neuropil and true rosettes (ETANTR) is rarely seen in the brainstem, and there are few case reports of brainstem ETANTR in the literature. Accordingly, the characteristics and the role of surgical treatment of this rare entity remain unclear. The authors present a case of brainstem ETANTR involving a 33-month-old boy along with a review of the literature and discuss the role of surgical removal in the treatment of this entity. In the authors' case, the tumor was surgically treated with subtotal resection, which resulted in improvement of the patient's preoperative symptoms. Chemotherapy was initiated but did not appear to be effective, radiotherapy was declined, and the boy died 6 months after the operation. Based on their analysis of 10 previously reported cases and their own case, the authors conclude that, with respect to survival, surgery may be beneficial even in cases of ETANTR in the brainstem. They note, however, that further studies with a large number of cases are needed to validate the role of surgical treatment in brainstem ETANTR.

Qualitative analysis of spinal intramedullary lesions using PET/CT

OBJECT Although the usefulness of PET for brain lesions has been established, few reports have examined the use of PET for spinal intramedullary lesions. This study investigated the diagnostic utility of PET/CT for spinal intramedullary lesions. METHODS l-[methyl-¹¹C]-methionine (MET)- or [¹⁸F]-fluorodeoxyglucose (FDG)-PET/CT was performed in 26 patients with spinal intramedullary lesions. The region of interest (ROI) within the spinal cord parenchyma was placed manually in the axial plane. Maximum pixel counts in the ROIs were normalized to the maximum standardized uptake value (SUV_max) using subject body weight. For FDG-PET the SUV_max was corrected for lean body mass (SUL_max) to exclude any influence of the patient's body shape. Each SUV was analyzed based on histopathological results after surgery. The diagnostic validity of the SUV was further compared with the tumor proliferation index using the MIB-1 monoclonal antibody (MIB-1 index). RESULTS A total of 16 patients underwent both FDG-PET and MET-PET, and the remaining 10 patients underwent either FDG-PET or MET-PET. Pathological diagnoses included high-grade malignancy such as glioblastoma multiforme, anaplastic astrocytoma, or anaplastic ependymoma in 5 patients; low-grade malignancy such as hemangioblastoma, diffuse astrocytoma, or ependymoma in 12 patients; and nonneoplastic lesion including cavernous malformation in 9 patients. Both FDG and MET accumulated significantly in high-grade malignancy, and the SUL_max and SUV_max correlated with the tumor proliferation index. Therapeutic response after chemotherapy or radiation in high-grade malignancy was well monitored. However, a significant difference in SUL_max and SUV_max for FDG-PET and MET-PET was not evident between low-grade malignancy and nonneoplastic lesions. CONCLUSIONS Spinal PET/CT using FDG or MET for spinal intramedullary lesions appears useful and practical, particularly for tumors with high-grade malignancy. Differentiation of tumors with low-grade malignancy from nonneoplastic lesions may still prove difficult. Further technological refinement, including the selection of radiotracer or analysis evaluation methods, is needed.

Efficacy of arachnoid plasty with collagen sheets and fibrin glue: An in vitro experiment and a case review

Background:

Postoperative subdural fluid collection sometimes occurs after clipping of cerebral aneurysms. Arachnoid plasty is used to prevent such postoperative complications; however, the optimal materials for arachnoid plasty remain unclear. In this study, we aimed to clarify the optimal materials for arachnoid plasty and report our experience of arachnoid plasty after clipping of unruptured aneurysms.

Methods:

In an in vitro experiment, adhesive strengths of three materials permitted for use in the intradural space, such as collagen sheets, gelatin sponge, and oxidized cellulose sheets, were measured by assessing their water pressure resistance. Then, 80 consecutive cases surgically treated unruptured cerebral aneurysms were retrospectively reviewed to examine the occurrence rate of postoperative subdural fluid collection.

Results:

The collagen sheet exhibited the greatest adhesive strength, so we used collagen sheets for the arachnoid plasty procedures. In all of these cases, arachnoid plasty was performed with fibrin glue-soaked collagen sheets. No postoperative subdural fluid collection, inflammation, or allergic reactions occurred in any case.

Conclusions:

The present study suggests that collagen sheet might be one of the optimal materials for arachnoid plasty. This technique is simple and may be effective to prevent subdural fluid collection after clipping.

Imaging the passionate stage of romantic love by dopamine dynamics

Using [¹¹C]raclopride, a dopamine D₂/D₃ receptor antagonist, we undertook a positron emission tomography (PET) study to investigate the involvement of the dopaminergic neurotransmitter system when subjects viewed the pictures of partners to whom they were romantically attached. Ten subjects viewed pictures of their romantic partners and, as a control, of friends of the same sex for whom they had neutral feelings during the PET study. We administered [¹¹C]raclopride to subjects using a timing for injecting the antagonist which had been determined in previous studies to be optimal for detecting increases in the amount of dopamine released by stimulation. The results demonstrated statistically significant activation of the dopaminergic system in two regions, the medial orbitofrontal cortex (mOFC) and medial prefrontal cortex, the former of which has been strongly implicated in a variety of rewarding experiences, including that of beauty and love. A positive correlation was obtained in mOFC between excitement levels and dopaminergic activation only in the love but not in the control condition.

Twelve-year-old girl with intracranial epidural abscess and sphenoiditis

We report the case of a 12-year-old girl with an intracranial epidural abscess and sphenoiditis. Although she had no history of sinusitis, she developed acute severe headache, fever, and vomiting. Emergent CT and MRI showed a spherical space-occupying lesion of diameter 3 cm in the right cranial fossa with rim enhancement. The lesion was thought to be an epidural abscess adjacent to the right sphenoiditis. On the basis of the MRI findings, we performed emergent surgery to drain the abscess and sinusitis because of severe and rapidly worsening headaches. The patient showed great improvement the day after the operation. Intravenous antibiotics were administered for 8 days. She has completely recovered, with neither sequelae nor recurrence at 7 months after the operation. We believe that this report will be a useful reference for cases of acute onset headache and may be helpful in diagnosis and treatment decisions for severe sinusitis-related intracranial abscess in childhood.

Neural decoding of single vowels during covert articulation using electrocorticography

The human brain has important abilities for manipulating phonemes, the basic building blocks of speech; these abilities represent phonological processing. Previous studies have shown change in the activation levels of broad cortical areas such as the premotor cortex, the inferior frontal gyrus, and the superior temporal gyrus during phonological processing. However, whether these areas actually convey signals to representations related to individual phonemes remains unclear. This study focused on single vowels and investigated cortical areas important for representing single vowels using electrocorticography (ECoG) during covert articulation. To identify such cortical areas, we used a neural decoding approach in which machine learning models identify vowels. A decoding model was trained on the ECoG signals from individual electrodes placed on the subjects' cortices. We then statistically evaluated whether each decoding model showed accurate identification of vowels, and we found cortical areas such as the premotor cortex and the superior temporal gyrus. These cortical areas were consistent with previous findings. On the other hand, no electrodes over Broca's area showed significant decoding accuracies. This was inconsistent with findings from a previous study showing that vowels within the phonemic sequence of words can be decoded using ECoG signals from Broca's area. Our results therefore suggest that Broca's area is involved in the processing of vowels within phonemic sequences, but not in the processing of single vowels.

Analysis of progression and recurrence of meningioma using (11)C-methionine PET

OBJECTIVE

The recurrence rate of meningioma after surgery is high, and progression is often observed. The risk factors for recurrence and progression are not clear. We evaluated the risk factors for recurrence and progression in meningioma using (11)C-methionine (MET) positron emission tomography (PET).

METHODS

Thirty-seven patients (mean follow-up, 80 months) with an intracranial meningioma were enrolled. MET PET was performed before treatment between 1995 and 2010, and patients were followed up in an out-patient clinic. Surgery was performed in 33 patients, and a wait-and-see approach was taken in four patients. We evaluated the extent of tumor resection, location, WHO grade, Ki-67 labeling index, and lesion to normal ratio (LN ratio) of MET uptake.

RESULTS

Six of the surgical cases had a recurrence, and two of the observation-only patients had tumor progression. A high LN ratio of MET uptake was a significant risk factor for recurrence and progression with univariate analysis. The area under the curve of receiver operating characteristic curve for the LN ratio of MET uptake was 0.754, and the optimal cutoff value was 3.18 (sensitivity 63 %, specificity 79 %). With multivariate analysis, a high LN ratio of MET uptake, non-gross total resection, and a high WHO grade were significant risk factors for progression and recurrence.

CONCLUSION

A high LN ratio of MET uptake was a risk factor for tumor progression and recurrence. The advantage of MET PET is that it is not invasive and can easily be used to evaluate the whole tumor.

Normal variation of diffusion tensor parameters of the spinal cord in healthy subjects at 3.0-Tesla

AIMS

The purposes of the present study were to clarify the normal variation and to determine the normal reference values of diffusion tensor (DT) parameters (mean diffusivity [MD] and fractional anisotropy [FA]) of the spinal cord in single-shot fast spin-echo-based sequence at 3.0-Tesla (3T).

MATERIALS AND METHODS

Thirty healthy subjects (mean age = 44.2 years, range = 20-72 years) were enrolled for this study. Mean values of MD and FA in six spinal levels (C2/3, C3/4, C4/5, C5/6, C6/7, and C7/Th1) were measured. Mean values, variances, and distributions of the MD and FA in each spinal level were analyzed. Age-dependent change of MD and FA as well as correlation between MD and FA was also analyzed.

RESULTS

At all spinal levels, the values can be considered to be Gaussian distribution in MD but not in FA. A significant statistical negative correlation was observed between aging and the values of MD (r = 0.429, P = 0.018), but insignificant between the values of FA (P = 0.234). A slight significant statistical negative correlation was observed between the values of MD and FA (r = 0.156, P = 0.037). One way repeated measures analysis of variance indicated the significant difference between the spinal levels in both MD (P = 0.003) and FA (P < 0.0001).

CONCLUSIONS

The analyzed data in the present study would be helpful for comparison when investigating the spinal condition of spinal disorders.

Extension of Quantifiable Modification of sLORETA for Induced Oscillatory Changes in Magnetoencephalography

Quantifiable modification of standardized low-resolution brain electromagnetic tomography (sLORETA-qm), which is one of the non-adaptive beamformer spatial filtering techniques, has been applied to source localization and quantification of evoked field or oscillatory changes in magnetoencephalography (MEG). Here, we extended this technique to induced oscillatory brain activity changes, so-called event-related desynchronization or event-related synchronization. For localizing of significantly activated brain areas at the whole-brain level, permutation tests and multiple comparison corrections with false discovery rate were applied. Induced β- and γ-band oscillatory changes by right hand clenching task were demonstrated as an example of simple induced brain activity.

Analysis of venous drainage from sylvian veins in clinoidal meningiomas

OBJECTIVE

To categorize clinoidal meningiomas according to their venous drainage patterns, and use each category as a guideline to establish an appropriate surgical strategy.

METHODS

We performed a retrospective analysis of 22 consecutive surgically treated patients with clinoidal meningioma who underwent preoperative digital subtraction angiography to examine the characteristics of the venous drainage system. These patients were categorized into: 1) cortical type in which the sylvian vein did not drain medially but drained to cortical veins, 2) sphenobasal type in which the sylvian vein drained into the pterygoid plexus, or 3) cavernous type in which the sylvian vein drained into the cavernous sinus directly through the sphenoparietal sinus. We tailored the surgical strategy to preserve these draining veins.

RESULTS

Preoperative angiographic evaluation demonstrated 14 patients (63.6%) with cortical type, 6 patients (27.3%) with sphenobasal type, and 2 patients (9.1%) with the cavernous type. In most cases, no restriction from the venous structure was observed because the sylvian vein belonged to the cortical type. However, in the case of the sphenobasal or sphenoparietal type, the surgical strategy seemed to be tailored to preserve the venous drainage system.

CONCLUSIONS

The surgical risk from venous complication in the treatment of clinoidal meningiomas appears to be low; however, there are likely to be patients that require a tailored surgical approach to avoid venous complications. Detailed preoperative assessment of anatomic structure and consideration of the optimal surgical strategy are critical to improve treatment outcomes.

Tentorial schwannoma mimicking meningioma

A 58-year-old woman presented with a rare tentorial schwannoma manifesting as a chief complaint of headache. Magnetic resonance imaging showed an infratentorial extra-axial mass lesion with both cystic and solid components and dural tail sign. The tumor was easily separated from the surrounding structures, and the origin was apparently the tentorial branch of the trigeminal nerve. Tentorial schwannoma should be considered in the differential diagnosis of mixed cystic and solid mass lesions associated with the tentorium around the ambient cistern.

Medulloblastoma manifesting as sudden sensorineural hearing loss

We present a rare case of medulloblastoma which presented with unilateral sudden sensorineural hearing loss as an initial symptom. A 19-year-old man was admitted to our hospital with a chief complaint of dizziness and facial numbness on the right side. His illness had begun two years previously with sudden hearing loss on the right side, for which he had been treated as an idiopathic sudden hearing loss. Magnetic resonance imaging demonstrated abnormal signals located mainly in the right middle cerebellar peduncle. We performed partial resection of the tumor by suboccipital craniotomy. The histopathological diagnosis was medulloblastoma. Intrinsic brain tumor is an extremely rare cause of sudden sensorineural hearing loss and is therefore easily overlooked as was in the present case. The present case highlights not only the need to evaluate patients with sudden sensorineural hearing loss by magnetic resonance imaging but also the importance of paying attention to intrinsic lesions involving the brainstem. Although this condition like the presented case might be rare, intrinsic brain tumor should be considered as a potential cause of sudden sensorineural hearing loss, as it may be easily missed leading to a delay in appropriate treatment.

Surgical management of petroclival chordomas: report of eight cases

In the management of skull base chordomas, surgical treatment is essential to achieve long-term control. A petroclival chordoma growing laterally in the skull base is one of the most challenging tumors for neurosurgeons. We have treated petroclival chordomas based on the principle of maximal surgical resection of the tumor with minimal morbidity. Lateral skull base approaches were used to approach petroclival chordomas in eight patients. The surgical procedure involved removal of soft tumor tissue and extensive drilling of adjacent bony structures. Gross total resection of the tumor was achieved in six patients. Subtotal resection in the remaining two patients was associated with acceptable morbidity. In cases of petroclival chordomas, lateral skull base approaches can be used as a primary procedure, although those approaches may be associated with high rates of morbidity and mortality.

Focal adhesive arachnoiditis of the spinal cord: Imaging diagnosis and surgical resolution

Background:

Although adhesive arachnoiditis of the spinal cord can cause progressive symptoms associated with syringomyelia or myelomalacia, its surgical resolution based on the imaging diagnosis is not well characterized. This study aims to describe the use of imaging for the diagnosis of focal adhesive arachnoiditis of the spinal cord and its surgical resolution using microsurgical arachnoidolysis.

Materials and Methods:

Four consecutive patients with symptomatic syringomyelia or myelomalacia caused by focal adhesive arachnoiditis underwent microsurgical arachnoidolysis. Comprehensive imaging evaluation using constructive interference in steady-state (CISS) magnetic resonance imaging (MRI) or myelographic MR imaging using true fast imaging with steady-state precession (TrueFISP) sequences was included before surgery to determine the surgical indication.

Results:

In all four patients a focal adhesion was identified at the cervical or thoracic level of the spinal cord, a consequence of infection or trauma. Three patients showed modest or minor improvement in neurological function, and one patient was unchanged after surgery. The syringomyelia or myelomalacia resolved after surgery and no recurrence was noted within the follow-up period, which ranged from 5 months to 30 months.

Conclusions:

MRI diagnosis of focal adhesive arachnoiditis is critical to determine the surgical indication. Microsurgical arachnoidolysis appears to be a straightforward method for stabilizing the progressive symptoms, though the procedure is technically demanding.

Non-normalized individual analysis of statistical parametric mapping for clinical fMRI

BACKGROUND

Pre-operative evaluation to localize function within the cerebral cortices is essential before brain surgery. Blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) has been used for this purpose.

AIMS

To obtain clearer and more understandable functional images.

PATIENTS AND METHODS

Ten patients with brain tumors underwent fMRI including hand-gripping and word generation tasks. The statistical parametric mapping (SPM) approach was used for subsequent analysis to localize the motor or language functions. SPM includes image pre-processing, statistical computation, and significance testing. In order to demonstrate a spatial relationship between the lesions and a functioning area in the individual structural MR images, normalization to the Montreal Neurological Institute coordinates was intentionally not performed.

RESULTS

In seven cases out of 10, the patient's motor area was clearly visualized. Language areas were also demonstrated in seven cases.

CONCLUSIONS

We conclude that application of SPM (version 8) analysis to non-normalized individual data for the purpose of performing pre-operative fMRI is a useful method for investigation of functional localization.