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Objectives: This study noninvasively examined the electrical conductivity (σ) characteristics of diffuse gliomas using MRI and tested its validity.Methods: MRI including a 3D steady-state free precession (3D SSFP) sequence was performed on 30 glioma patients. The σ maps were reconstructed from the phase images of the 3D SSFP sequence. The σ histogram metrics were extracted and compared among the contrast-enhanced (CET) and noncontrast-enhanced tumour components (NCET) and normal brain parenchyma (NP). Difference in tumour σ histogram metrics among tumour grades and correlation of σ metrics with tumour grades were tested. Validity of σ measurement using this technique was tested by correlating the mean tumour σ values measured using MRI with those measured ex vivo using a dielectric probe.Results: Several σ histogram metrics of CET and NCET of diffuse gliomas were significantly higher than NP (Bonferroni-corrected p ≤ .045). The maximum σ of NCET showed a moderate positive correlation with tumour grade (r = .571, Bonferroni-corrected p = .018). The mean tumour σ measured using MRI showed a moderate positive correlation with the σ measured ex vivo (r = .518, p = .040).Conclusions: Tissue σ can be evaluated using MRI, incorporation of which may better characterise diffuse gliomas.Key Points: • This study tested the validity of noninvasive electrical conductivity measurements by MRI. • This study also evaluated the electrical conductivity characteristics of diffuse glioma. • Gliomas have higher electrical conductivity values than the normal brain parenchyma. • Noninvasive electrical conductivity measurement can be helpful for better characterisation of glioma. [ABSTRACT FROM AUTHOR]

A 5-year-old boy underwent biopsy of an intra-axial calcified tumor in the hypothalamus, which was incidentally found. Based on the presence of ganglion-like cells combined with glial cell element, the pathological diagnosis was ganglioglioma. Because the tumor grew gradually in size over the next 2 years, he underwent chemotherapy with temozolomide. However, at 8 years of age, the boy developed hydrocephalus and the cystic lesion had re-grown. Endoscopic cyst fenestration and tumor biopsy was performed, and pathological diagnosis was tentatively oligodendroglioma based on the presence of tumor cells with a perinuclear halo. At 10 years of age, hydrocephalus recurred and the cystic lesion had re-grown. A second round of endoscopic cyst fenestration and tumor biopsy led to a pathological diagnosis of pilocytic astrocytoma due to a biphasic appearance with areas of dense tumor cells and microcystic areas, tumor cells with eosinophilic processes, and the presence of an eosinophilic granular body. Genetic analysis of the first biopsy successfully identified the BRAF V600E mutation. Because pathological diagnosis of diencephalic low-grade glioma harboring BRAF V600E would be sometimes difficult due to pathological variations, pathological diagnosis should be performed under the consideration of molecular diagnosis of BRAF V600E for optimal diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Purpose: Metabolic activity and hypoxia are both important factors characterizing tumor aggressiveness. Here, we used F-18 fluoromisonidazole (FMISO) and F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) to define metabolically active hypoxic volume, and investigate its clinical significance in relation to progression free survival (PFS) and overall survival (OS) in glioblastoma patients. Experimental Design: Glioblastoma patients ( n = 32) underwent FMISO PET, FDG PET, and magnetic resonance imaging (MRI) before surgical intervention. FDG and FMISO PET images were coregistered with gadolinium-enhanced T1-weighted MR images. Volume of interest (VOI) of gross tumor volume (GTV) was manually created to enclose the entire gadolinium-positive areas. The FMISO tumor-to-normal region ratio (TNR) and FDG TNR were calculated in a voxel-by-voxel manner. For calculating TNR, standardized uptake value (SUV) was divided by averaged SUV of normal references. Contralateral frontal and parietal cortices were used as the reference region for FDG, whereas the cerebellar cortex was used as the reference region for FMISO. FDG-positive was defined as the FDG TNR ≥1.0, and FMISO-positive was defined as FMISO TNR ≥1.3. Hypoxia volume (HV) was defined as the volume of FMISO-positive and metabolic tumor volume in hypoxia (hMTV) was the volume of FMISO/FDG double-positive. The total lesion glycolysis in hypoxia (hTLG) was hMTV × FDG SUVmean. The extent of resection (EOR) involving cytoreduction surgery was volumetric change based on planimetry methods using MRI. These factors were tested for correlation with patient prognosis. Results: All tumor lesions were FMISO-positive and FDG-positive. Univariate analysis indicated that hMTV, hTLG, and EOR were significantly correlated with PFS ( p = 0.007, p = 0.04, and p = 0.01, respectively) and that hMTV, hTLG, and EOR were also significantly correlated with OS ( p = 0.0028, p = 0.037, and p = 0.014, respectively). In contrast, none of FDG TNR, FMISO TNR, GTV, HV, patients' age, or Karnofsky performance scale (KPS) was significantly correlated with PSF or OS. The hMTV and hTLG were found to be independent factors affecting PFS and OS on multivariate analysis. Conclusions: We introduced hMTV and hTLG using FDG and FMISO PET to define metabolically active hypoxic volume. Univariate and multivariate analyses demonstrated that both hMTV and hTLG are significant predictors for PFS and OS in glioblastoma patients. [ABSTRACT FROM AUTHOR]

Background: Bevacizumab (BEV), a humanized monoclonal antibody, become a currently important chemotherapeutic option for the patients with recurrent glioma. The aim of this retrospective study is to investigate whether 18F-Fluoromisonidazole (FMISO) PET have the potential to detect BEV-resistant gliomas in the early-stage. Methods: We reviewed the FMISO PET and MRI appearances before and 3 to 4 courses after BEV treatment on 18 recurrent glioma patients. FMISO accumulation was assessed by visual inspection and semi-quantitative values which were tumor-to-normal (T/N) ratio and hypoxic volume. MRI responses were evaluated based on RANO (Response Assessment in Neuro-Oncology) criteria. The prognostic analysis was performed in relation to the response assessment by FMISO PET and MRI using overall survival (OS) after BEV application. Results: After BEV application, MRI revealed partial response in 14 of 18 patients (78%), of which 9 patients also demonstrated decreased FMISO accumulation. These 9 patients (50%) were classified as “MRI-FMISO double responder”. As for the other 5 patients (28%), FMISO accumulation volumes increased or remained stable after BEV treatment although partial responses were achieved on MRI. Therefore, these cases were classified as “MRI-only responder”. The remaining 4 patients (22%) did not show treatment response on FMISO PET or MRI (“non-responder”). MRI-FMISO double responders showed significantly longer OS than that in other groups (median 12.4 vs 5.7 months; P < 0.001), whereas there were no overall survival difference between MRI-only responders and non-responders (median OS, 5.7 and 4.8 months; P = 0.58). Among the pre-treatment clinical factors, high FMISO T/N ratio was a significant prognostic factor of overall survival in these patients under the assessment of Cox proportional hazard model. Conclusions: Recurrent gliomas with decreasing FMISO accumulation after short-term BEV application could derive a survival benefit from BEV treatment. Change in FMISO PET appearance can identify BEV-resistant gliomas in early-stage regardless of MRI findings in a comprehensible way. [ABSTRACT FROM AUTHOR]