Suguru Inao

Dynamics of cerebral blood flow and metabolism in patients with cranioplasty as evaluated by 133Xe CT and 31P magnetic resonance spectroscopy.

OBJECTIVE--Prolonged improvement in neurological and mental disorders has been seen after only cranioplasty in patients initially treated with external decompression for high intracranial pressure. The objective was to evaluate, using 133Xe CT and 31P magnetic resonance spectroscopy (MRS), how restoring the bone itself can influence cerebral blood flow and cerebral energy metabolism after high intracranial pressure is attenuated. METHODS--Seven patients (45-65 years old) who had undergone external decompression to prevent uncontrollable intracranial hypertension after acute subarachnoid haemorrhage were evaluated. Cerebral blood flow and metabolic changes were evaluated before and after cranioplasty. RESULTS--The ratio of phosphocreatine to inorganic phosphate (PCr/Pi), which is a sensitive index of cerebral energy depletion, was calculated and beta-ATP was measured. The cerebral blood flow value in the thalamus was normalised, from 44 (SD 9) to 56 (SD 8) ml/100 g/min (P < 0.01) and the value in the hemisphere increased from 26 (SD 3) to 29 (SD 4) ml/100 g/min on the side with the bone defect. The PCr/Pi ratio improved greatly from 2.53 (SD 0.45) to 3.01 (SD 0.24) (P < 0.01). On the normal side, the values of cerebral blood flow and PCr/Pi increased significantly (P < 0.01) after cranioplasty, possibly due to transneural suppression. The pH of brain tissue was unchanged bilaterally after cranioplasty. CONCLUSION--Cranioplasty should be carried out as soon as oedema has disappeared, because a bone defect itself may decrease cerebral blood flow and disturb energy metabolism.

Expression and Distribution of Beta Amyloid Precursor Protein and Beta Amyloid Peptide in Reactive Astrocytes After Transient Middle Cerebral Artery Occlusion

Summary Background. In the brains of Alzheimers disease patients, beta amyloid protein is the major component of senile plaque. In ischemic stress, beta amyloid precursor protein (APP) and beta amyloid peptide are reported to be upregulated. Method. Using Male Wistar-ST rats, expression and distribution of APP and beta amyloid peptide were examined immunohistochemically after transient ischemia induced by a 2-h middle cerebral artery occlusion (MCAO). After reperfusion for 3, 7, 14, 30 and 60 days, brains were removed and immunostaining was performed. Findings. The reactive astrocytes with APP were observed in the periphery of infarct from 3 days to 60 days post-occlusion. The immunoreactivity of beta amyloid peptide was also localized in the reactive astrocytes in the peripheral zone of infarct at 7, 14, and 30 days post-occlusion. However, beta amyloid expression was not identified at 3 days or 60 days post MCAO. Transient ischemia temporarily induced beta amyloid peptide expression in reactive astrocytes, but this expression peaked at 30 days and disappeared at 60 days. Interpretation. These findings suggested that beta amyloid peptide was derived from the processing of APP produced in the same reactive astrocytes and the production of the peptide stopped within 60 days after the ischemic stress.

Human visual motion areas determined individually by magnetoencephalography and 3D magnetic resonance imaging

We used magnetoencephalography to study inter‐individual locational difference in the extrastriate region which responds to visual motion. Magnetic responses to visual motion onset from the right temporo‐occipital area were recorded from 12 subjects. All the subjects had clear responses to apparent or random dot coherent motion. The origins of these responses was investigated by use of the single equivalent current dipole model. The nearest scalp to the origin also was identified for each subject, which may be useful in transcranial stimulation studies. Although the magnetic responses of all the subjects should have the same functional properties; be related to neural activities synchronized exclusively to the onset of motion, the estimated origins varied greatly among the subjects. The location of origin could be classified as one of three types: temporo‐occipital, occipital, or parietal, according to the sulcal anatomy investigated in the individuals three‐dimensional magnetic resonance image. Temporo‐occipital types were found for seven subjects, and anatomically the regions were around human MT/V5. Two subjects had the occipital type, with regions posterior to the anatomical MT/V5 and corresponding to V3A anatomically. The other three subjects had origins classified as the parietal type dorso‐rostral to the anatomical MT/V5, with regions around the posterior end of the superior temporal sulcus. Although all these cortical regions appear to be related to the neural process of visual motion, whether they correspond functionally to the same names or migrated MT/V5 must now be determined. Hum. Brain Mapping 11:33–45, 2000.

Neural Activation of the Brain with Hemodynamic Insufficiency

Little is known about how ischemia affects hemodynamic responses to neural activation in the brain. We compare the effects of a motor activation task and a cerebral vasodilating agent, acetazolamide (ACZ), on regional cerebral blood flow (rCBF) in primary sensorimotor cortex (PSM) in six patients with major cerebral artery steno-occlusive lesions without paresis of the upper extremities. Quantitative rCBF was measured in all patients using H215 O autoradiographic method and positron emission tomography. The CBF was determined at rest, during a bimanual motor activation task, and 10 minutes after ACZ administration. With bimanual motor activation, rCBF increased significantly in both PSM compared with at rest (P < 0.01 on lesion side, and P < 0.02 on contralateral side). However, rCBF did not increase after ACZ injection in the PSM on the lesion side, whereas rCBF increased significantly in the contralateral PSM after ACZ injection compared with the level at rest. This result suggests that despite a decreased hemodynamic reserve, there is a nearly normal flow response to neural activation, indicating that the mechanism of vasodilation responsible for perfusion change is different for acetazolamide and neural activation. The relations among neural activation, hemodynamic status, and cerebral metabolism in the ischemic stroke patients are discussed.

Malignant transformation-related genes in meningiomas: allelic loss on 1p36 and methylation status of p73 and RASSF1A.

OBJECT Analysis of meningiomas supports the suggestion that loss of heterozygosity (LOH) of chromosome arm 1p plays an important role in malignancy. The aim of this study was to identify genes related to meningioma progression from the benign state to the atypical and anaplastic states by examining 1p LOH and the promoter methylation of RASSF1A and p73. METHODS The authors studied 40 surgical specimens (22 WHO Grade I, 11 Grade II, and seven Grade III) obtained in 37 patients with meningioma. The LOH at 1p36 was analyzed using microsatellite markers, and promoter methylation of p73 and RASSFIA was analyzed using methylation-specific polymerase chain reaction. RESULTS No 1p LOH was detected in the Grade I tumors, whereas it was detected in more than 80% of the Grade II and III tumors. Methylation of the p73 promoter was observed in 81.8 and 71.4% of the Grade II and III tumors, respectively, but it was not observed in any of the Grade I tumors; methylation of the RASSF1A promoter was observed in 18.2, 63.6, and 42.9% of the Grade I, II, and III tumors, respectively. Interestingly, 1p LOH and p73 promoter hypermethylation were detected in the malignantly transformed tumors but not in the lower-grade primary ones. CONCLUSIONS Based on the hypothesis that meningiomas cumulatively acquire genetic alterations and thus progress from the benign to the atypical and anaplastic states, genetic alterations in the methylation status of p73 or RASSF1A along with 1p LOH may result in the malignant transformation of a meningioma. This type of genetic fingerprint may play both diagnostic and therapeutic roles.

BALANCED IRRIGATION-SUCTION TECHNIQUE WITH A MULTIFUNCTIONAL SUCTION CANNULA AND ITS APPLICATION FOR INTRAOPERATIVE HEMORRHAGE IN ENDOSCOPIC EVACUATION OF INTRACEREBRAL HEMATOMAS: TECHNICAL NOTE

OBJECTIVEEndoscopic evacuation of intraoperative hemorrhage is proving to be increasingly useful and effective. For general agreement that endoscopic evacuation has advantages over craniotomy, secure hemostatic procedures are crucial. TECHNIQUEThis technical note focuses on hemostatic procedures for managing intraoperative hemorrhage. Handling of the multifunctional suction cannula and its application for balanced irrigation-suction are fully explained in this report. resultsNearly complete evacuation of hematoma was achieved in all 15 cases. In 9 cases of intraoperative arterial bleeding, secure hemostatis has been accomplished. No surgical complications or rebleeding occurred. CONCLUSIONEven careful atraumatic evacuation of a hematoma can sometimes result in intraoperative hemorrhage. Repeated irrigation and point suctioning may be necessary to keep the operating field clear. A multifunctional suction cannula would be useful for maintaining irrigation and suction balance. Coagulation of a bleeding artery can be performed under clear visualization. A balanced irrigation-suction technique results in secure hemostasis.

COMPARISON OF VASODILATORY EFFECT OF CARBON DIOXIDE INHALATION AND INTRAVENOUS ACETAZOLAMIDE ON BRAIN VASCULATURE USING POSITRON EMISSION TOMOGRAPHY

Carbon dioxide (CO2) and acetazolamide are increasingly being used as vasodilators to detect cerebrovascular reserve capacity in patients of chronic cerebrovascular disease. The functional cerebrovascular reserve or ability of cerebral vessels to lower their resistance in response to decrease in cerebral perfusion pressure is expressed as change in cerebral blood flow from baseline under a vasodilatory stimuli. Theoretically a vasodilator causing maximum vasodilation, and thereby expressing complete reserve capacity would be more suitable for such a purpose. We quantitatively compared the vasodilating effect of 5% CO2 inhalation and 1 g of intravenous acetazolamide by positron emission tomography. Cerebrovascular reserve was quantified in six patients with chronic cerebrovascular disease in the same sitting, using oxygen-15 labeled water (H2(15)O) positron emission tomography at rest, during 5% CO2 inhalation and after 1 g intravenous acetazolamide. A significant linear correlation in both nonlesion hemisphere (r = 0.701, p < 0.001) and in lesion hemisphere (r = 0.626, p < 0.005) was found between CO2 and acetazolamide for cerebrovascular reserve capacity. This correlation improved by considering cerebrovascular reserve per unit change in arterial carbon dioxide (r = 0.744, p < 0.001 in nonlesion hemisphere and r = 0.721, p < 0.001 in lesion hemisphere). The quantitative value of global reserve capacity was different by CO2 stimuli (5.2%) and acetazolamide (49.7%). Though a similar vasodilatory response is elicited by both vasodilators, acetazolamide seems to be more potent and therefore should be preferred to detect patients with exhausted cerebrovascular reserve capacity.

Primary intraosseous orbital hemangioma : a case report and review of the literature

Primary intraosseous orbital hemangiomas are rare tumors. Only 25 cases have been reported in the literature. Very few of them have multiple orbital bone involvement. We report a case with extensive involvement of the orbital roof, the medial and lateral walls of the orbit, and the lesser and greater wings of the sphenoid, and describe a unilateral extradural frontotemporal approach to excise the tumor and decompress the right superior orbital fissure and both optic nerves. A brief clinical and radiological review of the literature is presented.

Early Recovery and Better Evacuation Rate in Neuroendoscopic Surgery for Spontaneous Intracerebral Hemorrhage Using a Multifunctional Cannula: Preliminary Study in Comparison With Craniotomy

Neuroendoscopy is a promising therapeutic option for spontaneous intracerebral hemorrhage (ICH). We sought to compare the clinical outcomes between neuroendoscopic surgery and craniotomy for spontaneous ICH. We retrospectively analyzed the clinical and radiographic data of 43 patients treated with 23 neuroendoscopic procedures (endoscopy group) and 20 microsurgical procedures (craniotomy group). Rebleeding rate, surgical complications, and/or death were identified as primary clinical endpoints during the 2-month postoperative follow-up period. Evacuation rate, Glasgow Coma Scale (GCS) score at day 7, and Glasgow Outcome Scale (GOS) score were compared as well. A composite primary endpoint was observed in 5 cases (11.6%), including 1 postoperative death in the endoscopy group (4.3%) and 4 postoperative deaths in the craniotomy group (20.0%). No rebleeding was observed in the endoscopy group. The evacuation rate was significantly higher in the endoscopy group compared with the craniotomy group (99.0% vs 95.9%; P < .01). Mean GCS score at day 7 was 12 for the endoscopy group and 9.1 for the craniotomy group (P < .05). The mean change in GCS score was +4.8 for the endoscopy group and -0.1 for the craniotomy group (P < .001). Our data indicate that in patients with ICH, endoscopic surgery is safe and feasible, and may promote earlier recovery. Our results warrant a future prospective, randomized, controlled efficacy trial.

Assessment of T1 time course changes and tissue-blood ratios after Gd-DTPA administration in brain tumors

Sequential T1 changes in brain tumor tissue after Gd-DTPA administration were investigated in 10 patients, including 4 meningiomas, 2 gliomas, 3 metastatic cerebral tumors and 1 brain abscess. T1 values were measured serially for 60 minutes following Gd-DTPA injection using a magnetic focusing technique. In vitro T1 of the whole blood samples was also comparatively examined. Time processes in the tissue-blood ratio (TBR) were calculated from two-point relaxation rates at 5 and 30 minutes. The obtained ratios of TBR were ranged from 1.0 to 3.0, probably depending on histological types of brain tumor (the value of 1.0 to 1.5 for meningioma and 1.5 to 3.0 for glioma and metastatic tumor). No significant changes in the T1 value were observed in the examined normal tissue and peritumoral edema. These results indicate that Gd-DTPA plays an important role not only as an image enhancer for tumor tissue but also as an indicator for estimating the blood-brain barrier function.