Usefulness of Preoperative Surgical Simulation with Three-Dimensional Fusion Images for Resection of Cerebral Cavernous Malformations Near Broca's Area.

Treating subcortical brain lesions in or near eloquent areas is challenging not only because lesions must be resected while preserving brain tissue involved in essential functions, but also because lesions often cannot be easily identified from the surface of the brain. Here, we report 2 cases of cerebral cavernous malformations near Broca's area. In both cases, lesions were surgically removed by utilizing three-dimensional fusion images created using preoperative magnetic resonance imaging and computed tomography data. Excisions were completed without any worsening of speech function, and the use of presurgical simulations was found to be useful in the design and execution of the actual operations. The technique described in this report serves as a useful tool in simulating surgical strategies by using brain gyri and sulci as surgical landmarks. Furthermore, in contrast to other intraoperative techniques, this method can aid in shortening the duration of surgery and can help limit damage to eloquent areas of the brain.

Natural dissociation of olivine to (Mg,Fe)SiO3 perovskite and magnesiowustite in a shocked Martian meteorite.

We report evidence for the natural dissociation of olivine in a shergottite at high-pressure and high-temperature conditions induced by a dynamic event on Mars. Olivine (Fa(34-41)) adjacent to or entrained in the shock melt vein and melt pockets of Martian meteorite olivine-phyric shergottite Dar al Gani 735 dissociated into (Mg,Fe)SiO(3) perovskite (Pv)+magnesiowüstite (Mw), whereby perovskite partially vitrified during decompression. Transmission electron microscopy observations reveal that microtexture of olivine dissociation products evolves from lamellar to equigranular with increasing temperature at the same pressure condition. This is in accord with the observations of synthetic samples recovered from high-pressure and high-temperature experiments. Equigranular (Mg,Fe)SiO(3) Pv and Mw have 50-100 nm in diameter, and lamellar (Mg,Fe)SiO(3) Pv and Mw have approximately 20 and approximately 10 nm in thickness, respectively. Partitioning coefficient, K(Pv/Mw) = [FeO/MgO]/[FeO/MgO](Mw), between (Mg,Fe)SiO(3) Pv and Mw in equigranular and lamellar textures are approximately 0.15 and approximately 0.78, respectively. The dissociation of olivine implies that the pressure and temperature conditions recorded in the shock melt vein and melt pockets during the dynamic event were approximately 25 GPa but 700 °C at least.

Severe parkinsonism following endoscopic third ventriculostomy for non-communicating hydrocephalus--case report.

A 23-year-old male with non-communicating hydrocephalus caused by intraventricular hemorrhage from an arteriovenous malformation was treated by endoscopic third ventriculostomy (ETV) after repeated ventricular cerebrospinal fluid drainage and removal of ventriculoperitoneal shunt due to infection. Postoperatively, the patient developed robust rigidity and akinesia with mutism, suggesting secondary parkinsonism. These symptoms showed marked improvement after administration of levodopa, and were not aggravated after discontinuation. The pathophysiology of this case might involve dysfunction of the dopaminergic system caused by repeated compression and release of the paraventricular white matter. Careful perioperative management not leading to excessive dilation of the the ventricles should be considered for ETV for non-communicating hydrocephalus to avoid this unexpected complication.

Source analysis of the magnetic field evoked during self-paced finger movements.

OBJECTIVE: The aim of this study is to investigate a source of cortical magnetic fields evoked by index finger movements. METHODS: We analysed both movement-related cortical fields (MRCFs) and somatosensory-evoked fields (SEFs) by single equivalent current dipole (ECD) method in six healthy subjects. Dipole locations were superimposed on MR images of each individual subject. RESULTS: The first component after finger movement (movement-evoked field I, MEFI) was observed in all subjects. The dipole of MEFI was oriented posteriorly, and was located on the posterior wall of the central sulcus of the hemisphere contralateral to the movement. The SEFs showed three major components: N20m, P30m and P60m. The dipoles of P30m and P60m were orientated posteriorly, similarly to the MEFI dipole, while that of N20m was orientated anteriorly. The dipole location of MEFI was closely located to P60m, not to N20m and P30m. The mean location of the MEFI dipole was significantly (p<0.05) superior to N20m. CONCLUSION: These findings suggest that MEFI would be generated in the sensory area (area 3b) affected by multiple afferents and activities, and that the source of the MEFI is not identical to that of the N20m component.

[A case of carotid stenting via the transbrachial approach in the bovine arch].

We report our experience in carotid stenting via the transbrachial approach in patients with anomalous origin of the left common carotid artery, the so-called bovine arch, in which both the right common carotid artery and the left common carotid artery arise from the brachiocephalic artery. Via percutaneous access to the right brachial artery, a 6Fr Shuttle sheath is advanced into the aortic arch to cannulate the left common carotid artery. A Guardwire distal-protection balloon is positioned within the left internal carotid artery distal to the stenosis. The lesion is dilated, followed by satisfactory deployment and dilation of a 6Fr Precise stent. Carotid stenting via the brachial artery in bovine arch appears feasible as an alternative to standard femoral access.

Motor-related intracortical steal phenomenon detected by multichannel functional near-infrared spectroscopy imaging.

BACKGROUND: Patients with severe cerebral ischemia may lose autoregulation to increase cerebral blood flow following neural activity. Although the steal phenomenon under conventional cerebral blood flow study has been known as a high-risk factor for stroke, the cerebral oxygen hemodynamics in ischemic patients during functional activation has not been thoroughly investigated. In this study, we present rare cases with intracortical steal phenomenon during motor tasks detected by multichannel functional near-infrared spectroscopy before and after surgery. METHODS: The relative concentration change of oxygenated, deoxygenated and total hemoglobin in and around the primary sensorimotor cortex during contralateral hand grasping was investigated in 11 patients with severe internal carotid artery stenosis. RESULTS: In 3 patients, the concentration of total hemoglobin around the primary sensorimotor cortex significantly decreased in response to motor stimulation and returned to baseline soon after termination of the motor task. This phenomenon partially disappeared postoperatively in all patients who underwent surgery. The remaining 8 patients showed no signs of total hemoglobin decrease in and around the sensorimotor cortex. In 9 patients, lack of decrease in deoxygenated hemoglobin in the center of the primary motor cortex during the motor task was observed and 3 of them showed significant increase in deoxygenated hemoglobin. CONCLUSIONS: We have demonstrated that in some patients with severe ischemia, an abnormal motor-related steal phenomenon can be observed. This phenomenon can be modulated by surgical intervention and might imply the severity of ischemia.

HAADF-STEM study on the early stage of precipitation in aged Al-Ag alloys.

We report on the structure of Ag precipitates in aged Al-Ag alloys using transmission electron microscopy and high-angle annular detector darkfield scanning transmission electron microscopy (HAADF-STEM). Irregularly shaped small Ag particles of 1-2 nm dominate the alloy annealed at 140 degrees C for 10 h. These particles are present also within large precipitates (10-50 nm), which are often characterized by their {100} and {110} facets. In addition, atomic-resolution HAADF-STEM images revealed that Ag atoms tend to form {111} planar clusters, which criss-cross a colony of the irregularly shaped small Ag precipitates.

Recovery of audition after favorable resection of vagal schwannoma.

Two patients with vagal schwannoma manifesting as deafness with no lower cranial nerve paresis were treated surgically. A 42-year-old male underwent partial resection of the tumor, which was tightly adhered to the cranial nerves, to prevent lower cranial nerve paresis. A 29-year-old female underwent total removal of the tumor without complications. The patients recovered useful audition with no postoperative deficit.

Incommensurate modulation in the microporous silica SSZ-24.

A detailed investigation of the structure of microporous silica, SSZ-24, is presented. It is shown by X-ray powder diffraction and (29)Si MAS NMR experiments that the structure deviates from the previously proposed AlPO(4)-5-type structure. At room temperature, electron diffraction (ED) patterns exhibit extra diffraction spots, which can be attributed to an incommensurate structural modulation along the c axis. This in turn results in a pleat pattern in real space with two different intervals arranged aperiodically along the c axis, as observed with high-resolution electron microscopy (HREM). The modulated structure may easily turn into a disordered one through excessive electron irradiation or heat-treatment. In order to understand the origin of the modulation, soft phonon-modes of the ideal premodulated structure were analyzed by the use of the rigid-unit-mode model. The distribution of soft modes in reciprocal space might correspond roughly to diffuse streaks that could be observed in the diffraction patterns at higher temperatures. It was found that several phonon branches soften at specific wave vectors, which are incommensurate with respect to the original period and might be responsible for the modulation. We present a simple analytic treatment to deduce the wave vectors and associated displacement eigenvectors for the incommensurate soft-modes.

Gliofibrous nodule in the cerebello-medullary fissure.

An extra-axial nodule in the cerebello-medullary fissure is described, occurring in a 27-year-old-woman. MRI and CT scans revealed the lesion was a non-enhanced round mass, which was associated with mild atrophy of the surrounding cerebellum, but with no perifocal edema. In the surgical observation, the mass was white, elastic and hard, well demarcated and localized in the cerebello-medullary fissure. Histologically, the lesion was composed of astrocytes and collagen-producing fibroblasts with no anaplasia. These findings suggested that the lesion was hamartomatous, but not neoplastic. This type of gliofibrous nodule has not been previously reported.