Clinical characteristics and prognosis of Glioblastoma patients with infratentorial recurrence.

BACKGROUND: Glioblastoma (GBM) infrequently recurs in the infratentorial region. Such Infratentorial recurrence (ITR) has some clinically unique characteristics, such as presenting unspecific symptoms and providing patients a chance to receive additional radiotherapy. However, the clinical significances of ITR are not well studied. METHODS: We reviewed newly diagnosed isocitrate dehydrogenase (IDH)-wildtype GBM patients treated at our institution between October 2008 and December 2018. ITR was defined as any type of recurrence in GBM, including dissemination or distant recurrence, which primarily developed in the supratentorial region and recurred in the infratentorial region. RESULTS: Of 134 patients with newly diagnosed IDH-wildtype GBM, six (4.5%) were classified as having ITR. There was no significant difference in median duration from the first surgery to ITR development between patients with and without ITR (12.2 vs. 10.2 months, P = 0.65). The primary symptoms of ITR were gait disturbance (100%, n = 6), dizziness (50.0%, n = 3), nausea (33.3%, n = 2), and cerebellar mutism (16.7%, n = 1). In four cases (66.7%), symptoms were presented before ITR development. All patients received additional treatments for ITR. The median post-recurrence survival (PRS) of ITR patients was significantly shorter than that of general GBM patients (5.5 vs. 9.1 months, P = 0.023). However, chemoradiotherapy contributed to palliating symptoms such as nausea. CONCLUSIONS: ITR is a severe recurrence type in GBM patients. Its symptoms are neurologically unspecific and can be overlooked or misdiagnosed as side effects of treatments. Carefully checking the infratentorial region, especially around the fourth ventricle, is essential during the GBM patient follow-up.

The clinical characteristics and outcomes of incidentally discovered glioblastoma.

OBJECTIVE: With an increase in the number of imaging examinations and the development of imaging technology, a small number of glioblastomas (GBMs) are identified by incidental radiological images. These incidentally discovered glioblastomas (iGBMs) are rare, and their clinical features are not well understood. Here, we investigated the clinical characteristics and outcomes of iGBM. METHODS: Data of newly diagnosed iGBM patients who were treated at our institution between August 2005 and October 2019 were reviewed. An iGBM was defined as a GBM without a focal sign, discovered on radiological images obtained for reasons unrelated to the tumor. Kaplan-Meier analysis was performed to calculate progression-free survival (PFS) and overall survival (OS). RESULTS: Of 315 patients with newly diagnosed GBM, four (1.3%) were classified as having iGBM. Health screening was the most common reason for tumor discovery (75.0%). The preoperative Karnofsky performance status score was 100 in three patients. Tumors were found on the right side in three cases. The mean volume of preoperative enhanced tumor lesion was 16.8 cm3. The median duration from confirmation of an enhanced lesion to surgery was 13.5 days. In all cases, either total (100%) or subtotal (95-99%) resections were achieved. The median PFS and OS were 10.5 and 20.0 months, respectively. CONCLUSIONS: The iGBMs were often small and in the right non-eloquent area, and the patients had good performance status. We found that timely therapeutic intervention provided iGBM patients with favorable outcomes. This report suggests that early detection of GBM may lead to a better prognosis.

Assessment of radiographic and prognostic characteristics of programmed death-ligand 1 expression in high-grade gliomas.

PURPOSE: Gliomas are characterized by immunosuppressive features. Programmed death-ligand 1 (PD-L1) is overexpressed and plays an important role in the immunosuppressive tumor microenvironments of gliomas. However, the radiographical and prognostic significance of PD-L1 expression remains unclear. METHODS: Using tissue microarrays, we evaluated PD-L1 expression and the presence of tumor-infiltrating CD4+ and CD8+T cells and CD204+macrophages using immunohistochemical analysis. Contrast enhancement area and fluid-attenuated inversion recovery (FLAIR) hyperintensity area were evaluated by two-dimensional analysis. Kaplan-Meier analysis was performed to evaluate the overall survival time in 44 patients with isocitrate dehydrogenase (IDH)-wildtype glioblastoma. RESULTS: We evaluated 71 patients with newly diagnosed high-grade gliomas who were treated between October 1998 and April 2012. PD-L1 expression was observed in 15 patients (21.1%). A significant association of PD-L1 expression with the CD4+ and CD8+ T cell densities, but not with CD204+ macrophage densities, was observed (p = 0.025, p = 0.0098, and p = 0.19, respectively). The FLAIR-to-enhancement ratio was significantly higher in PD-L1+ tumors than in PD-L1- tumors (p = 0.0037). PD-L1 expression did not show a significant association with the median survival time (PD-L1 + vs. PD-L1-: 19.2 vs 14.9 months; p = 0.39). CONCLUSION: PD-L1 expression was associated with CD4+ and CD8+ T cell infiltration, indicating a significant interplay between PD-L1 and immune cells. The positive correlation of PD-L1 expression with an increased FLAIR-to-enhancement ratio suggested that radiographical characteristics could reflect the immunological status. Our results did not support the prognostic impact of PD-L1 in patients with IDH-wildtype glioblastomas.

MGMT gene promoter methylation by pyrosequencing method correlates volumetric response and neurological status in IDH wild-type glioblastomas.

PURPOSE: Although the usefulness of O6-methylguanine DNA methyltransferase (MGMT) promoter methylation analysis for predicting response to chemoradiotherapy and the prognosis of patients with glioblastoma has been widely reported, there is still no consensus regarding how to define MGMT promoter methylation percentage (MGMTpm%) cutoffs by pyrosequencing method. The aim of this study was to determine the optimal cutoff value of MGMT promoter methylation status using volumetric analysis focused on the tumor volume ratio (TVR) measured by MRI. METHODS: This retrospective study included newly diagnosed IDH wild-type glioblastoma patients with residual tumor after surgery, followed by local radiotherapy with temozolomide. TVR was defined as the tumor volume at 6 months after the initial chemoradiotherapy administration divided by the tumor volume before the start of therapy. The mean MGMTpm% of 16 CpG islands (74-89) was analyzed using pyrosequencing. We statistically analyzed the correlation between MGMTpm%, TVR, and change in Karnofsky performance status. RESULTS: The study included 44 patients with residual tumors. Thirteen (92.9%) of 14 patients with MGMTpm% ≥ 23.9% showed 50% or more volumetric response, leading to prolonged survival, and 17 (70.8%) of 24 patients with MGMTpm% < 8.2% had progressive disease after initial chemoradiotherapy administration. Three (50.0%) of six patients with MGMTpm% 8.2% to < 23.9% had stable disease or partial response. CONCLUSION: Evaluation of MGMTpm% by pyrosequencing is important in predicting the volumetric response and prognosis of glioblastoma patients with residual tumors.

Continuing maintenance temozolomide therapy beyond 12 cycles confers no clinical benefit over discontinuation at 12 cycles in patients with IDH1/2-wildtype glioblastoma.

OBJECTIVE: The optimal duration of maintenance temozolomide therapy is controversial. We aimed to examine the clinical benefits of continuing temozolomide therapy beyond 12 cycles in patients with glioblastoma. METHODS: We included 41 patients with isocitrate dehydrogenase 1/2-wildtype glioblastoma, who received 12 or more cycles of temozolomide therapy between June 2006 and December 2019. We evaluated the outcome between 16 patients who continued temozolomide therapy beyond 12 cycles up to 24 cycles (≥13 cycles group) and 25 patients wherein temozolomide therapy was discontinued at 12 cycles (12 cycles group). RESULTS: The median progression-free survival and survival time after completing 12 cycles (residual progression-free survival and residual overall survival) did not differ between the 12 cycles group and ≥13 cycles group (residual progression-free survival: 11.3 vs. 9.2 months, P = 0.61, residual overall survival: 25.7 vs. 30.2 months, P = 0.76). Multivariate analysis including temozolomide therapy beyond 12 cycles, age at 12 cycles, Karnofsky performance status at 12 cycles, residual tumor at 12 cycles, maintenance therapy regimen and O-6-methylguanine deoxyribonucleic acid methyltransferase promoter methylation status revealed that extended temozolomide therapy beyond 12 cycles was not correlated with residual progression-free survival and residual overall survival (P = 0.80 and P = 0.41, respectively) but Karnofsky performance status at 12 cycles ≥80 was significantly associated with increased residual overall survival (P = 0.0012). CONCLUSIONS: Continuing temozolomide beyond 12 cycles confers no clinical benefit over the discontinuation of temozolomide at 12 cycles. Karnofsky performance status at 12 cycles ≥80 may serve as a novel predictive factor for long-term survival.

Outcomes of salvage fractionated re-irradiation combined with bevacizumab for recurrent high-grade gliomas that progressed after bevacizumab treatment*.

BACKGROUND: There is no standard treatment for patients with recurrent high-grade gliomas who progress after bevacizumab treatment. We evaluated the outcomes of re-irradiation combined with bevacizumab for patients refractory to bevacizumab. METHODS: Between January 2015 and September 2019, patients with progression after bevacizumab treatment were treated with re-irradiation combined with bevacizumab (25 Gy in five fractions). RESULTS: Fourteen patients [glioblastoma, isocitrate dehydrogenase (IDH) wild type (N = 6), glioblastoma, IDH mutant (N = 4), anaplastic astrocytoma, IDH wild type (N = 1), anaplastic astrocytoma, IDH mutant (N = 1), glioblastoma, not otherwise specified (N = 1) and radiologically diagnosed brainstem glioma (N = 1)] were included in this study. The median survival and progression-free survival times after re-irradiation combined with bevacizumab were 6.1 and 3.8 months, respectively. The 6-month survival and progression-free survival rates were 54.5 and 15.7%, respectively. Patients with a Karnofsky performance status of ≥70 tended to have longer median survival time (9.3 vs. 5.4 months, respectively; P = 0.058) and had a significantly longer median progression-free survival time (4.2 vs. 3.7 months, respectively; P = 0.046) than those with a Karnofsky performance status of <70. Four patients (28.6%) achieved a complete or partial radiological response, and three patients (21.4%) had an improved Karnofsky performance status after re-irradiation combined with bevacizumab. Grade 3/4 toxicities included leukopenia in four patients (28.6%), hypertension in three (21.4%), proteinuria in one (7.1%) and gastrointestinal hemorrhage in one (7.1%). CONCLUSIONS: Re-irradiation combined with bevacizumab for patients with recurrent high-grade gliomas who progress after bevacizumab treatment was feasible. Re-irradiation combined with bevacizumab is a potential treatment option, especially for patients with a Karnofsky performance status of ≥70.

[Intrameatal Aneurysm of Distal Anterior Inferior Cerebellar Artery Manifesting a Subarachnoid Hemorrhage:A Report of 2 Cases].

Two female patients presented with a subarachnoid hemorrhage because of ruptured intrameatal aneurysms of the distal anterior inferior cerebellar artery, which is extremely rare. Each patient underwent microsurgical direct neck clipping or trapping, as needed, by a retrosigmoid craniectomy with an unroofing of the internal auditory meatus. After the surgery, both patients manifested low hearing ability. In recent years, an endovascular therapy or occipital artery-anterior inferior cerebellar artery bypass with aneurysm trapping are being employed to treat intrameatal aneurysms. We present a review of literature, and referred features and treatment techniques for intrameatal aneurysms.

Pyriproxyfen enhances the immunoglobulin G immune response in mice.

Pyriproxyfen is a juvenile hormone mimic of vital importance for insect development with little risk to humans. This study was performed to investigate whether large doses of pyriproxyfen affect the immune response in mammals. Mice were immunized thrice with ovalbumin in 5% ethanol, with or without pyriproxyfen or alum. Large doses of pyriproxyfen (9 or 15 mM) significantly enhanced specific total IgG immune response. This enhancement was no longer present 24 hr after treatment with pyriproxyfen. These results suggest that pyriproxyfen is a safe chemical. Moreover, pyriproxyfen induced higher titers of IgG2a and enhanced tumor necrosis factor-alpha and gamma-interferon responses whereas alum induced IgG1 with enhanced interleukin-4 and -10. These observations indicate that the mechanism of immune enhancement by pyriproxyfen may differ from that of alum.

Combination of asleep and awake craniotomy as a novel strategy for resection in patients with butterfly glioblastoma: Two case reports.

Background: Several studies have reported that gross total resection contributes to improved prognosis in patients with butterfly glioblastoma (bGBM). However, it sometimes damages the corpus callosum and cingulate gyrus, leading to severe neurological complications. Case Description: We report two cases of bGBM that was safely and maximally resected using brief and exact awake mapping after general anesthesia. Two patients had butterfly tumors in both the frontal lobes and the genu of the corpus callosum. Tumor resection was first performed on the nondominant side under general anesthesia to shorten the resection time and maintain patient concentration during awake surgery. After that, awake surgery was performed for the lesions in the dominant frontal lobe and genu of the corpus callosum. Tumor resection was performed through minimal cortical incisions in both frontal lobes. Postoperative magnetic resonance imaging showed gross total resection, and the patients had no chronic neurological sequelae, such as akinetic mutism and abulia. Conclusion: bGBM could be safely and maximally resected by a combination of asleep and brief awake resection, which enabled patients to maintain their attention to the task without fatigue, somnolence, or decreased attention. The bilateral approach from a small corticotomy can avoid extensive damage to the cingulate gyrus.

Assessment of therapeutic outcome and role of reirradiation in patients with radiation-induced glioma.

BACKGROUND: We sought to clarify the optimal follow-up, therapeutic strategy, especially the role of reirradiation, and the diagnostic impact of isocitrate dehydrogenase (IDH) 1 and 2 mutation status in patients with radiation-induced glioma (RIG). METHODS: We retrospectively reviewed the clinical characteristics and treatment outcomes of 11 patients with high-grade glioma who satisfied Cahan's criteria for RIG in our database during 2001-2021. IDH 1/2 mutations were analyzed by Sanger sequencing and/or pyrosequencing. RESULTS: The RIGs included glioblastoma with IDH 1/2 wild-type (n = 7), glioblastoma not otherwise specified (n = 2), anaplastic astrocytoma with IDH1/2 wild-type (n = 1), and anaplastic astrocytoma not otherwise specified (n = 1). The median period from primary disease and RIG diagnosis was 17 years (range: 9-30 years). All patients underwent tumor removal or biopsy, 5 patients postoperatively received reirradiation combined with chemotherapy, and 6 patients were treated with chemotherapy alone. The median progression-free and survival times were 11.3 and 28.3 months. The median progression-free survival time of patients treated with reirradiation and chemotherapy (n = 5) tended to be longer than that of patients that received chemotherapy alone (n = 6) (17.0 vs 8.1 months). However, the median survival time was similar (29.6 vs 27.4 months). Local recurrence was observed in 5 patients treated with chemotherapy alone, whereas in 2 patients among 4 patients treated with reirradiation and chemotherapy. None of the patients developed radiation necrosis. In one case, the primary tumor was diffuse astrocytoma with IDH2 mutant, and the secondary tumor was glioblastoma with IDH 1/2 wild-type. Based on the difference of IDH2 mutation status, the secondary tumor with IDH 1/2 wild-type was diagnosed as a de novo tumor that was related to the previous radiation therapy. CONCLUSIONS: RIG can occur beyond 20 years after successfully treating the primary disease using radiotherapy; thus, cancer survivors should be informed of the long-term risk of developing RIG and the need for timely neuroimaging evaluation. Reirradiation combined with chemotherapy appears to be feasible and has favorable outcomes. Determining the IDH1/2 mutational status is useful to establish RIG diagnosis when the primary tumor is glioma.

Clinical Application of Comprehensive Genomic Profiling Tests for Diffuse Gliomas.

Next-generation sequencing-based comprehensive genomic profiling test (CGPT) enables clinicians and patients to access promising molecularly targeted therapeutic agents. Approximately 10% of patients who undergo CGPT receive an appropriate agent. However, its coverage of glioma patients is seldom reported. The aim of this study was to reveal the comprehensive results of CGPT in glioma patients in our institution, especially the clinical actionability. We analyzed the genomic aberrations, tumor mutation burden scores, and microsatellite instability status. The Molecular Tumor Board (MTB) individually recommended a therapeutic agent and suggested further confirmation of germline mutations after considering the results. The results of 65/104 patients with glioma who underwent CGPTs were reviewed by MTB. Among them, 12 (18.5%) could access at least one therapeutic agent, and 5 (7.7%) were suspected of germline mutations. A total of 49 patients with IDH-wildtype glioblastoma showed frequent genomic aberrations in the following genes: TERT promoter (67%), CDKN2A (57%), CDKN2B (51%), MTAP (41%), TP53 (35%), EGFR (31%), PTEN (31%), NF1 (18%), BRAF (12%), PDGFRA (12%), CDK4 (10%), and PIK3CA (10%). Since glioma patients currently have very limited standard treatment options and a high recurrence rate, CGPT might be a facilitative tool for glioma patients in terms of clinical actionability and diagnostic value.

Feasibility of Using a Pocket-Sized Ultrasound Device to Measure the Inferior Vena Cava Diameter of Patients With Heart Failure in the Community Setting: A Pilot Study.

Background: The incidence of heart failure as well as its treatment costs and rehospitalization rates are increasing worldwide. Physical assessment of elderly patients with heart failure living in their homes is challenging for community nurses. Pocket-sized echocardiographs will be useful for assessing the condition of the patients with heart failure during home-visit care. Objectives: This pilot study aimed to examine the feasibility of measuring the inferior vena cava (IVC) diameter using a pocket-sized ultrasound device. Methods: Nursing students were trained to use the pocket-sized ultrasound device (PUSD) for measuring the inferior vena cava diameter of a healthy subject. We evaluated the accuracy and rapidity of the nursing students' measurements compared with those of an expert sonographer. Results: In total, 83.3% of the participants accurately visualized the IVC using the PSUD. There was no significant difference in the mean IVC diameter between that measured by the students and the sonographer. In total, 25% of the participants accurately measured the IVC diameter. The mean measurement time was 201 seconds. Conclusion: Our training program allowed the participants to accurately visualize the IVC using the PSUD. However, these results on accuracy and measurement time still need to be improved before community nurses can use the PSUD during home visits.

Treatment of Fourth Ventricle Arachnoid Cyst via Anterior Hone of Lateral Ventricle Using Flexible Endoscope.

BACKGROUND: Arachnoid cysts are common anomalies in the intracranial region. However, an intraventricular arachnoid cyst is rare, and occurrence within the fourth ventricle is especially uncommon; only 16 cases have been described in the literature. Arachnoid cysts in the fourth ventricle may cause obstructive hydrocephalus or cerebellar ataxia or cranial nerve palsy. Treatment of a fourth ventricular arachnoid cyst is complete or partial resection via a midline suboccipital approach. Recently, endoscopic fenestration has become the procedure of choice in the treatment of arachnoid cysts in supratentorial locations, but as yet there has been no report of treating a fourth ventricle arachnoid cyst using a flexible endoscope. CASE DESCRIPTION: We present the case of a 43-year-old man who suffered a recurrence of an arachnoid cyst in the fourth ventricle that had been partially excised 8 years previously using midline suboccipital craniectomy. Because of concerns of adhesions following the previous craniectomy, we decided to perform endoscopic treatment via the anterior horn of the lateral ventricle. CONCLUSIONS: As per our knowledge, this is the first case reporting the treatment of an arachnoid cyst of the fourth ventricle using a flexible endoscope via the anterior horn of the lateral ventricle. This method can be used to treat arachnoid cysts of the fourth ventricle.

Real-time spectrum quantification of tumor-related fluorescence during neurosurgery: A preliminary report.

OBJECTIVES: The fluorescent dye, 5-aminolevulinic acid (5-ALA), is currently applied for fluorescence-guided resections of high-grade gliomas. Present limitations of this technique are qualitative and subjective analyses, which show little of the background structures. This paper describes the intraoperative quantitative analysis of fluorescence intensity, hot-spot enhancement by frame averaging, and observation of surrounding structures by using 1000-nm lighting in real time. PATIENTS AND METHODS: A sample of diluted protoporphyrin IX (PpIX) in a bottle and 37 samples from nine patients with brain lesions were involved in this study. In this preliminary study, we determined appropriate conditions for image averaging and filters and selected the most sensitive spectrometer. In addition, we utilized a 1000-nm lighting system to visualize surrounding structures with no interference from PpIX fluorescence. RESULTS: The novel system permitted the real-time quantitative analysis of PpIX fluorescence in operative fields by illuminating structures with 1000-nm-lighting. The real-time quantification provided subjective evaluations for surgical decision-making. We found good correlations between the fluorescence and PpIX contents in brain tissue. Furthermore, 1000-nm lighting visualized the anatomical structures and PpIX fluorescence simultaneously. CONCLUSION: The combination of spectroscopy and a 1000-nm lighting system could enable surgeons to create a spectrogram of targets of interest while observing background structures. The spectrometer that we selected is highly sensitive to PpIX fluorescence and enables us to perform intraoperative real-time tissue mapping. By using a real-time system, we can perform quantitative and objective evaluations to achieve maximal tumor resection.

Changes in elastic modulus of adhesive and adhesive-infiltrated dentin during storage in water.

The purpose of this study was to determine the elastic modulus of components at the resin-dentin interface with the use of an ultrasound device. Dentin slabs were obtained from freshly extracted bovine incisors shaped into a rectangular form. After demineralization, the dentin specimens were immersed in adhesives and polymerized. Adhesives were also polymerized and trimmed into the same shape as the dentin slabs. The specimens were then immersed in distilled water at 37 degrees C for up to one year. The ultrasound equipment employed in this study was a Pulser-Receiver, transducers and an oscilloscope. By measuring the longitudinal and shear wave sound velocities, the elastic modulus was determined. When the elastic modulus of adhesive resin-infiltrated demineralized dentin was compared with that of adhesives, slightly but significantly lower values were found for adhesives used in a self-etching primer system. On the other hand, a higher elastic modulus was observed for resin-infiltrated dentin than for an adhesive used in an etch and rinse system. The elastic modulus of the resin-infiltrated dentin prepared with the etch and rinse system was affected by long-term storage in distilled water.

Disconnection of the pathological connectome for multifocal epilepsy surgery.

OBJECTIVERecent neuroimaging studies suggest that intractable epilepsy involves pathological functional networks as well as strong epileptogenic foci. Combining cortico-cortical evoked potential (CCEP) recording and tractography is a useful strategy for mapping functional connectivity in normal and pathological networks. In this study, the authors sought to demonstrate the efficacy of preoperative combined CCEP recording, high gamma activity (HGA) mapping, and tractography for surgical planning, and of intraoperative CCEP measures for confirmation of selective pathological network disconnection.METHODSThe authors treated 4 cases of intractable epilepsy. Diffusion tensor imaging-based tractography data were acquired before the first surgery for subdural grid implantation. HGA and CCEP investigations were done after the first surgery, before the second surgery was performed to resect epileptogenic foci, with continuous CCEP monitoring during resection.RESULTSAll 4 patients in this report had measurable pathological CCEPs. The mean negative peak-1 latency of normal CCEPs related to language functions was 22.2 ± 3.5 msec, whereas pathological CCEP latencies varied between 18.1 and 22.4 msec. Pathological CCEPs diminished after complete disconnection in all cases. At last follow-up, all of the patients were in long-term postoperative seizure-free status, although 1 patient still suffered from visual aura every other month.CONCLUSIONSCombined CCEP measurement, HGA mapping, and tractography greatly facilitated targeted disconnection of pathological networks in this study. Although CCEP recording requires technical expertise, it allows for assessment of pathological network involvement in intractable epilepsy and may improve seizure outcome.

Influence of air-powder polishing on bond strength and surface-free energy of universal adhesive systems.

The influences of air-powder polishing with glycine or sodium bicarbonate powders on shear bond strengths (SBS) and surface-free energies of universal adhesives were examined. Scotchbond Universal Adhesive (SU, 3M ESPE), G-Premio Bond (GP, GC), Adhese Universal (AU, Ivoclar Vivadent), and All-Bond Universal (AB, Bisco) were used in this study. Bovine dentin surfaces were air polished with glycine or sodium bicarbonate powders prior to the bonding procedure, and resin pastes were bonded to the dentin surface using universal adhesives. SBSs were determined after 24-h storage in distilled water at 37°C. Surface-free energy was then determined by measuring contact angles using three test liquids on dentin surfaces. Significantly lower SBSs were observed for dentin that was air-powder polished and surface-free energies were concomitantly lowered. This study indicated that air-powder polishing influences SBSs and surface-free energies. However, glycine powder produced smaller changes in these surface parameters than sodium bicarbonate.

Passive language mapping combining real-time oscillation analysis with cortico-cortical evoked potentials for awake craniotomy.

OBJECTIVE Electrocortical stimulation (ECS) is the gold standard for functional brain mapping; however, precise functional mapping is still difficult in patients with language deficits. High gamma activity (HGA) between 80 and 140 Hz on electrocorticography is assumed to reflect localized cortical processing, whereas the cortico-cortical evoked potential (CCEP) can reflect bidirectional responses evoked by monophasic pulse stimuli to the language cortices when there is no patient cooperation. The authors propose the use of "passive" mapping by combining HGA mapping and CCEP recording without active tasks during conscious resections of brain tumors. METHODS Five patients, each with an intraaxial tumor in their dominant hemisphere, underwent conscious resection of their lesion with passive mapping. The authors performed functional localization for the receptive language area, using real-time HGA mapping, by listening passively to linguistic sounds. Furthermore, single electrical pulses were delivered to the identified receptive temporal language area to detect CCEPs in the frontal lobe. All mapping results were validated by ECS, and the sensitivity and specificity were evaluated. RESULTS Linguistic HGA mapping quickly identified the language area in the temporal lobe. Electrical stimulation by linguistic HGA mapping to the identified temporal receptive language area evoked CCEPs on the frontal lobe. The combination of linguistic HGA and frontal CCEPs needed no patient cooperation or effort. In this small case series, the sensitivity and specificity were 93.8% and 89%, respectively. CONCLUSIONS The described technique allows for simple and quick functional brain mapping with higher sensitivity and specificity than ECS mapping. The authors believe that this could improve the reliability of functional brain mapping and facilitate rational and objective operations. Passive mapping also sheds light on the underlying physiological mechanisms of language in the human brain.

Novel techniques of real-time blood flow and functional mapping: technical note.

There are two main approaches to intraoperative monitoring in neurosurgery. One approach is related to fluorescent phenomena and the other is related to oscillatory neuronal activity. We developed novel techniques to visualize blood flow (BF) conditions in real time, based on indocyanine green videography (ICG-VG) and the electrophysiological phenomenon of high gamma activity (HGA). We investigated the use of ICG-VG in four patients with moyamoya disease and two with arteriovenous malformation (AVM), and we investigated the use of real-time HGA mapping in four patients with brain tumors who underwent lesion resection with awake craniotomy. Real-time data processing of ICG-VG was based on perfusion imaging, which generated parameters including arrival time (AT), mean transit time (MTT), and BF of brain surface vessels. During awake craniotomy, we analyzed the frequency components of brain oscillation and performed real-time HGA mapping to identify functional areas. Processed results were projected on a wireless monitor linked to the operating microscope. After revascularization for moyamoya disease, AT and BF were significantly shortened and increased, respectively, suggesting hyperperfusion. Real-time fusion images on the wireless monitor provided anatomical, BF, and functional information simultaneously, and allowed the resection of AVMs under the microscope. Real-time HGA mapping during awake craniotomy rapidly indicated the eloquent areas of motor and language function and significantly shortened the operation time. These novel techniques, which we introduced might improve the reliability of intraoperative monitoring and enable the development of rational and objective surgical strategies.

Dentin bonding: influence of bonded surface area and crosshead speed on bond strength.

This study investigated the influence of the bonded surface area and the crosshead speed on the dentin bond strengths of self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and the facial surfaces were wet ground with #600 silicon carbide (SiC) paper. The dentin surfaces were treated according to the manufacturer's instructions. Adhesives were applied, and the resin composites were condensed into molds (2.4 or 4.0 mm in internal diameter), placed on to the dentin, and then light activated. Ten samples per test group were shear tested at crosshead speeds of 0.1, 0.5, 1.0, 5.0, and 10.0 mm/min. The results showed that higher crosshead speeds were associated with higher dentin bond strengths. This relationship was more significant for specimens with a smaller dentin bonding surface area.