The marked heterogeneity in glioblastoma (GBM) may be induced through dynamic differentiation and dedifferentiation process of glioma cells. The hypothesis that environmental stimuli induce these phenotypic changes, including dedifferentiation into the stem cell phenotype which contributes to the high invasiveness and resultant poor outcome in GBM patients, is recently being proven. In the process of cancer invasion and metastasis, the phenotypic change has also been described as epithelial-mesenchymal transition (EMT). This biological process is mainly dependent on hypoxic stimuli and also on transforming growth factor-β (TGF-β) released from glioma stem cells, mesenchymal stem cells, and myeloid cells recruited by hypoxia. The tumor microenvironment, especially hypoxia, inducing such dynamic phenotypic changes can be a good therapeutic target in the treatment of GBM.

The aim of this study was to evaluate the importance of pre- and post-operative volumetric measurement of the cerebellopontine angle (CPA) using 3 Tesla (3T) magnetic resonance imaging (MRI). Between April 2012 and December 2015, a total of 87 consecutive patients underwent microvascular decompression (MVD) for trigeminal neuralgia (TN), of whom 51 with primary TN caused by arterial compression were enrolled in this study. Bilateral CPA cistern volume was evaluated using 3T MRI before and after surgery; the Cistern Deviation Index was used to represent the degree of deviation of the CPA cistern. The relationships between CPA cistern volume and the etiology of TN were assessed, and post-operative changes in anatomical parameters were examined to determine differences between recurrent and non-recurrent patients with TN. The mean volume of the CPA cistern on the affected side was significantly smaller than the unaffected side (P < 0.001). Five of 51 (10%) patients experienced TN recurrence. The recurrent cases demonstrated significantly lower pre-operative Cistern Deviation Index scores than non-recurrent cases (P = 0.035). On the unaffected side—but not the affected side—post-operative volume reduction was significantly greater in the recurrence group than in the non-recurrence group (P = 0.004). The pre-operative Cistern Deviation Index was a useful parameter to predict the recurrence of TN. In recurrent patients, post-operative inflammatory reaction may extend to not only the operated side but also the healthy side and reduce the volume of the CPA cistern.

We investigated the safety and efficacy of consciousness sedation with dexmedetomidine (DEX) during the endovascular treatment of patients with acute cerebral infarction. Between April 2014 and November 2016, 38 stroke patients underwent endovascular thrombectomy (EVT) under local anesthesia and DEX consciousness sedation. The continuous intravenous administration of low-dose DEX (0.3–0.4 μg/kg/h) was started before entering the operating room. Patients not completely immobilized received an iv bolus of pentazocine (PTZ) and/or DEX (0.5–0.6 μg/kg/h). EVT was performed using a stent retriever and/or direct thrombo-aspiration. DEX sedation was stopped as soon as the operation was finished. A stent retriever was used in 8 (21.1%), direct thrombo-aspiration in 10 (26.3%), a stent retriever plus thrombo-aspiration in 14 (36.8%), and other devices in 6 patients (15.8%). Reperfusion exceeding 50% (thrombolysis in cerebral infarction >2b) was obtained in 30 patients (78.9%). DEX sedation alone immobilized 24 patients (63.2%), 14 (36.8%) required the additional injection of DEX or PTZ when EVT devices were navigated to the lesion. The administration of DEX and PTZ elicited no significant respiratory depression or cardiac dysfunction interfering with the procedures. Consciousness sedation by DEX was effective during the endovascular treatment of acute stroke patients. Under DEX sedation and the injection of PTZ, EVT was possible without significantly changing the patients’ vital signs.

Indocyanine green (ICG) emits fluorescence in the far-red domain under light excitation. ICG video angiography (ICG-VA) has been established as a useful method to evaluate blood flow in the operative field. We report the usefulness of ICG-VA for Sylvian fissure dissection in patients with subarachnoid hemorrhage (SAH). Subjects comprised 7 patients who underwent ICG-VA before opening the Sylvian fissure during neck clipping for ruptured cerebral aneurysm. We observed contrasted Sylvian veins before opening the Sylvian fissure using surgical microscopes. This procedure was termed “Sylvian ICG”. We observed ICG fluorescence quickly in all cases. Sylvian veins that appeared unclear in the standard microscopic operative field covered with subarachnoid hemorrhage were extremely clearly depicted. These Sylvian ICG findings were helpful in identifying entry points and the dissecting course of the Sylvian fissure. At the time of clipping, no residual fluorescence from Sylvian ICG was present, and aneurysm clipping was not impeded. Sylvian ICG for SAH patients is a novel technique to facilitate dissection of the Sylvian fissure. We believe that this technique will contribute to improved safety of clipping surgery for ruptured aneurysms.

Lumbar spondylolysis usually occurs as a stress fracture in the pars interarticularis of the vertebra. It is a prevalent sports-related disorder and a common cause of low back pain. We encountered five athletes (4 males, 1 female) with severe low back pain. Mean age was 14.5 years. All five patients were found to have bilateral pars fracture. In all cases, staging based on the findings from computed tomography scan of the right and left pars fracture was different. On short tau inversion recovery magnetic resonance imaging (STIR-MRI) of the comparatively newer more recently injured side, high signal intensity changes were obvious and dominant at the intra- and extraosseous area, which would indicate tissue edema and/or bleeding. Furthermore, the imaging findings corresponded to the side of the low back pain. In conclusion, STIR-MRI can effectively distinguish between painful pars fracture and painless pars fracture.

Intravascular lymphoma (IVL) has been characterized in many case reports by multiple white matter lesions reflecting ischemic changes. In contrast, there are very few case reports of cerebral or cerebellar hemorrhage resulting from IVL. A 56-year-old woman was referred to our department with two-week history of headache, nausea, and poor appetite. Gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) showed dilated veins on the cerebellar surface. No ischemic lesions were detected on diffusion-weighted images. Three days after admission, the patient had a large cerebellar hemorrhage, prompting emergency surgery. Unfortunately, the patient died on the 11th postoperative day. Massive CD20-positive lymphoma cells were recognized in the cerebellar veins, but not in the arteries or the parenchyma of the brain. This is the rare case report of a cerebellar hemorrhage complication from IVL that might have been caused by venous congestion. The dilated veins on the cerebellar surface recognized from the Gd-enhanced T1-weighted images were specific clues in this case.