Predicting Isocitrate Dehydrogenase Status in Non-Contrast-Enhanced Adult-Type Astrocytic Tumors Using Diffusion Tensor Imaging and 11C-Methionine, 11C-Choline, and 18F-Fluorodeoxyglucose PET.

We aimed to differentiate the isocitrate dehydrogenase (IDH) status among non-enhanced astrocytic tumors using preoperative MRI and PET. We analyzed 82 patients with non-contrast-enhanced, diffuse, supratentorial astrocytic tumors (IDH mutant [IDH-mut], 55 patients; IDH-wildtype [IDH-wt], 27 patients) who underwent MRI and PET between May 2012 and December 2022. We calculated the fractional anisotropy (FA) and mean diffusivity (MD) values using diffusion tensor imaging. We evaluated the tumor/normal brain uptake (T/N) ratios using 11C-methionine, 11C-choline, and 18F-fluorodeoxyglucose PET; extracted the parameters with significant differences in distinguishing the IDH status; and verified their diagnostic accuracy. Patients with astrocytomas were significantly younger than those with glioblastomas. The following MRI findings were significant predictors of IDH-wt instead of IDH-mut: thalamus invasion, contralateral cerebral hemisphere invasion, location adjacent to the ventricular walls, higher FA value, and lower MD value. The T/N ratio for all tracers was significantly higher for IDH-wt than for IDH-mut. In a composite diagnosis based on nine parameters, including age, 84.4% of cases with 0-4 points were of IDH-mut; conversely, 100% of cases with 6-9 points were of IDH-wt. Composite diagnosis using all parameters, including MRI and PET findings with significant differences, may help guide treatment decisions for early-stage gliomas.

Posttraumatic epilepsy in chronic disorders of consciousness due to severe traumatic brain injury after traffic accidents.

PURPOSE: To evaluate the clinical state of posttraumatic epilepsy (PTE) in patients with chronic disorders of consciousness (CDC) due to severe traumatic brain injury (STBI) after traffic accidents and clarify the risk factors for seizure occurrence in such patients. METHODS: Two hundred ninety-three patients with CDC due to STBI (mean age at admission [±standard deviation]: 36.4 ± 17.9 years; men: 71.7 %; mean duration of injury to admission: 416 ± 732 days; mean hospitalization time: 899 ± 319 days) were enrolled in this study. We retrospectively investigated the relationship between seizure conditions (type and frequency) and clinical data, including age, sex, pathological types of brain injury, with/without surgical intervention, degree of CDC, and administration of antiseizure medications (ASMs). RESULTS: Overall, 52.9 % (n = 155/293) and 64.2 % of the patients (n = 183/of 285 patients surviving at discharge) were administered ASMs at admission and discharge, respectively. One hundred thirty-two patients (45.1 %) experienced epileptic seizures during hospitalization, and the mean seizure frequency was 4.0 ± 0.4 times per year. In multivariate analysis, significant and independent risk factors of seizure occurrence were revealed to be male sex, high National Agency for Automotive Safety and Victims' Aid score, hypoxic encephalopathy, and history of the neurosurgical operations. CONCLUSION: The high prevalence of PTE in patients with CDC due to STBI, and the significant and independent risk factors for seizure occurrence in the chronic clinical phase were revealed. We expect that this study will aid toward improving clinical assessment and management of epileptic seizures in the population.

Resection of positive tissue on methionine-PET is associated with improved survival in glioblastomas.

BACKGROUND AND PURPOSE: The volume of excised tumor in contrast-enhanced areas evaluated via magnetic resonance imaging is known to have a strong influence on the survival of patients with glioblastoma (GBM). In this study, we investigated the effect of tumor resection on the survival of patients with GBM in the 11 C-methionine (MET) accumulation area using MET-positron emission tomography (MET-PET). METHODS: A total of 26 patients (median age, 69 years; 15 males) who had undergone tumor resection and MET-PET before and after surgery, after being newly diagnosed with GBM, were included in the study. MET-PET before and after tumor resection were compared. The association between the decrease in the maximum standardized uptake value (SUV) of the tumor divided by the normal cortical mean SUV (%; ΔT/N), the MET extent of resection (MET-EOR) from the % reduction in the MET accumulation area (%), and residual MET accumulation area (in cm3 ; MET-residual tumor volume [RTV]), as well as the survival time of patients with GBM, were evaluated via univariate analysis. RESULTS: ΔT/N were positively associated with survival (hazard ratio [HR], 0.98 [95% confidence interval (CI), 0.97-0.99], p = .02). MET-RTV revealed a negative association with survival (HR, 1.02 [95% CI, 1.01-1.04], p = .04). Additionally, MET-EOR showed a strong trend with survival (HR, 0.99 [95% CI, 0.97-1.01], p = .06). CONCLUSIONS: Surgical resection of MET-accumulated areas in GBM significantly prolongs the survival of patients with GBM. However, a prospective large-scale multicenter study is needed to confirm our findings.

Differentiation of astrocytoma between grades II and III using a combination of methionine positron emission tomography and magnetic resonance spectroscopy.

Objective: This study aimed to establish a method for differentiating between grades II and III astrocytomas using preoperative imaging. Methods: We retrospectively analyzed astrocytic tumors, including 18 grade II astrocytomas (isocitrate dehydrogenase (IDH)-mutant: IDH-wildtype = 8:10) and 56 grade III anaplastic astrocytomas (37:19). We recorded the maximum methionine (MET) uptake ratios (tumor-to-normal: T/N) on positron emission tomography (PET) and three MRS peak ratios: choline (Cho)/creatine (Cr), N-acetyl aspartate (NAA)/Cr, and Cho/NAA, between June 2015 and June 2020. We then evaluated the cut-off values to differentiate between grades II and III. We compared the grading results between contrast enhancement effects on MR and combinational diagnostic methods (CDM) on a scatter chart using the cutoff values of the T/N ratio and MRS parameters. Results: The IDH-mutant group showed significant differences in the Cho/NAA ratio between grades II and III using univariate analysis; however, multiple regression analysis results negated this. The IDH-wildtype group showed no significant differences between the groups. Contrast enhancement effects also showed no significant differences in IDH status. Accordingly, regardless of the IDH status, no statistically independent factors differentiated between grades II and III. However, CDMs showed higher sensitivity and negative predictive value in distinguishing them than MRI contrast examinations for both IDH statuses. We demonstrated a significantly higher diagnostic rate of grade III than of grade II with CDM, which was more striking in the IDH-mutant group than in the wild-type group. Conclusions: CDM could be valuable in differentiating between grade II and III astrocytic tumors.

Combining methionine-PET and MRI fluid-attenuated inversion-recovery mismatch to determine glioma molecular subtype.

BACKGROUND AND PURPOSE: 11 C-methionine (MET)-PET is a useful tool in neuro-oncology. The T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign on MRI is a characteristic finding in lower grade gliomas with isocitrate dehydrogenase (IDH) mutations and the absence of the 1p/19q codeletion; however, the T2-FLAIR mismatch sign has low sensitivity in differentiating gliomas and does not aid in identifying glioblastomas with IDH mutations. We therefore investigated the efficacy of the combination of the T2-FLAIR mismatch sign and MET-PET for accurately determining the molecular subtype of gliomas of all grades. METHODS: The present study comprised 208 adult patients diagnosed with supratentorial glioma confirmed by molecular genetics and histopathology. The ratio of the maximum lesion MET accumulation to the mean normal frontal cortex MET accumulation (T/N) was measured. The presence or absence of the T2-FLAIR mismatch sign was determined. The presence or absence of the T2-FLAIR mismatch sign and the MET T/N ratio were compared between glioma subtypes to evaluate individual and combined utility in identifying gliomas with IDH mutations and no 1p/19q codeletion (IDHmut-Noncodel) or gliomas with IDH mutations (IDHmut). RESULTS: The addition of MET-PET to MRI for the presence of the T2-FLAIR mismatch sign improved diagnostic accuracy, with the area under the curve values increasing from .852 to .871 for IDHmut-Noncodel and from .688 to .808 for IDHmut. CONCLUSIONS: The combination of the T2-FLAIR mismatch sign and MET-PET may provide improved diagnostic utility in differentiating gliomas according to molecular subtype, particularly in determining IDH mutation status.

A case of segmental arterial mediolysis with subarachnoid hemorrhage due to anterior cerebral artery dissection followed by internal carotid artery dissection.

BACKGROUND: Segmental arterial mediolysis (SAM) causes subarachnoid hemorrhage (SAH) due to intracranial aneurysm rupture and arterial dissection. We encountered a case of SAM-related SAH due to ruptured dissection of the A1 segment of the anterior cerebral artery concomitant with internal carotid artery (ICA) dissection. CASE DESCRIPTION: A 53-year-old man presented with SAH due to a ruptured right A1 dissecting aneurysm. The aneurysm was trapped; however, 7 days after the onset of SAH, he experienced right hemiparesis and aphasia. Angiography showed left ICA dissection; urgent carotid artery stenting was performed, leading to symptom improvement. Abdominal computed tomography angiography showed aneurysms of the celiac and superior mesenteric arteries. He was diagnosed with SAM based on clinical, imaging, and laboratory findings. CONCLUSION: In the acute phase of SAM-related SAH, cerebral ischemia could occur due to both cerebral vasospasm and intracranial or cervical artery dissection.

Vascular events from carotid artery atherosclerosis after radiation therapy for laryngeal and hypopharyngeal cancer: the incidence and risk factors.

In this retrospective cohort study, we evaluated the incidence of vascular events from carotid artery atherosclerosis after radiotherapy indication for laryngeal and hypopharyngeal cancer. From January 2007 to December 2016, we investigated 111 laryngeal/hypopharyngeal cancer patients who underwent curative radiotherapy and were followed up for ≥1 year (median follow-up duration, 60 months). We evaluated the incidence of vascular events from carotid artery atherosclerosis, defined as a transient ischemic attack or an atherothrombotic cerebral infarction, or from undergoing treatment such as carotid artery stenting for carotid artery stenosis. The median radiation dose was 66 Gy (range, 60-74); 48 patients (43.2%) received concurrent chemotherapy. The 5-year overall survival was 86.2%. Six patients required treatment for carotid artery disease. Carotid stenting was performed in three patients with carotid artery stenosis; three patients developed atherosclerotic cerebral infarction and received medical treatment, with a median of 51.7 months (range, 0.3-78.3) after radiotherapy initiation. The vascular event occurrence rate was 5.4% within 5 years and 10.7% within 8 years. In the univariate analysis, dyslipidemia, diabetes mellitus, and carotid calcification were significant factors for event occurrence. Because three out of six cases occurred out of the irradiated field, no carotid artery or carotid bulb dosimetric parameters showed significant correlation. As laryngeal/hypopharyngeal cancer patients, particularly with complications including dyslipidemia and diabetes mellitus, are at a high risk of carotid artery stenosis after radiotherapy, long-term carotid artery evaluation is necessary. Early intervention by stroke specialists can reduce the risk of fatal cerebral infarction.

In-stent hypodense area at two weeks following carotid artery stenting predicts neointimal hyperplasia after two years.

Introduction It has not been reported how long the follow-up study after carotid artery stenting (CAS) should be continued. The purpose of the present study is to clarify the dynamic change of the in-stent neointimal layer and residual arterial lumen by two years following CAS using three-dimensional computed tomography angiography (3D CTA) with volume rendering. Methods Thirty-six stented carotid arteries in 34 consecutive patients were examined by 3D CTA with volume rendering at two weeks and 3, 6, 12, 24 months of follow-up. Results An in-stent hypodense area could be detected in 10 of 36 (27.8%) carotid arteries at two weeks after CAS. In-stent hypodense areas gradually declined thereafter by three months. In the course of longer follow-up, the layer of the in-stent hypodense area (neointimal hyperplasia) continued to grow in size for up to 24 months. Patients with an in-stent hypodense area at two weeks have a thicker layer of neointimal hyperplasia at 24 months than patients without in-stent hypodense area at two weeks' follow-up. The predictive factors for growing neointimal hyperplasia at 24 months in multiple regression analysis are ulcer formation in pretreatment stenosis and the thickness of in-stent hypodense area at two weeks following CAS. Conclusion Our results suggest that follow-up study should be continued for a longer period even if in-stent restenosis could not be detected at one year following CAS. Especially in cases with ulcer formation in pretreatment stenosis and with a subacute in-stent hypodense area after CAS, longer follow-up is strongly recommended.