A new method for producing temporary complete cerebral ischemia in rats.

A new model of temporary complete cerebral ischemia was developed and tested in 64 rats. With use of microsurgical techniques, both pterygopalatine and external carotid arteries were occluded and the basilar artery was coagulated to reduce potential collateral CBF during ischemia. After this preliminary five-vessel occlusion, temporary global ischemia was induced by occluding the common carotid arteries (CCAs) with microclips. To validate the method, CBF was measured autoradiographically in 24 anatomical regions at death after 5 min of ischemia or after 15 min of ischemia followed by 5 min of reperfusion. Mean arterial blood pressure and arterial blood gases remained stable under controlled endotracheal ventilation and anesthesia (halothane, 70% N2O, and 30% O2) throughout the CBF experiments, except for a 10-15% increase in mean arterial blood pressure for 1-5 min after bilateral CCA occlusion. After the initial five-vessel occlusion, the EEG did not change, and local CBF levels were comparable to those in anesthetized non-surgical controls. When the CCAs were occluded, the EEG flattened rapidly; after 5 min of ischemia, autoradiography showed no detectable blood flow in the forebrain and cerebellum. The local CBF levels measured after 15 min of temporary global ischemia and 5 min of reperfusion demonstrated relatively homogeneous postischemic hyperperfusion; only two of eight rats had several 1- to 3-mm areas of no-reflow. Survival studies showed increasing motor impairment after 10, 15, 30, and 60 min of temporary CCA occlusion. Ischemic neuronal damage was observed histologically in the hippocampus and basal ganglia 24 h after 10 min of temporary ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary culture of human leptomeningeal cells in serum-free medium.

Human leptomeningeal (LM) cells were grown in serum-free medium supplemented with insulin, transferrin and bovine serum albumin. The cultured cells maintained the polygonal morphology characteristic of leptomeningeal cells. Electronmicroscopic and immunofluorescence examinations revealed interdigitation of cell membranes, invagination of cytoplasm into the nucleus, specialized intercellular junctions and the presence of cytokeratin. These characteristics are consistent with previous reports characterizing LM cells. This serum-free culture system may facilitate the in vitro study of the leptomeninges.

Developmental changes of cerebral blood flow and oxygen metabolism in children.

BACKGROUND AND PURPOSE: Normal values for cerebral blood flow (CBF) and metabolism in adults are well established, but not for children. Our goal, therefore, was to clarify functional developmental changes of the brain in children in relation to CBF and oxygen metabolism. METHODS: We measured regional CBF (rCBF), regional cerebral metabolic rate for oxygen (rCMRO2), and regional oxygen extraction fraction (rOEF), using positron emission tomography (PET). We performed 30 PET studies in 24 children ages 10 days to 16 years (nine boys, 15 girls), using a steady inhalation method with C(15)O2, (15)O2, and 15CO in order to measure rCBF, rCMRO2, and rOEF, respectively. Regions of interest were set in the primary cerebral areas (sensorimotor, visual, temporal, and parietal cortex), cerebral association areas (frontal and visual association), basal ganglia (lenticular and thalamus), and posterior fossa (brain stem and cerebellar cortex). Subjects were grouped by age (< 1, 1 to < 3, 3 to < 8, and > or = 8 years), and the absolute values of the parameters were compared with those obtained from 10 healthy adults. RESULTS: rCBF and rCMRO2 were lower in the neonatal period than in older children and adults, and increased significantly during early childhood. rCBF was higher as compared with adults, peaking around age 7, whereas rCMRO2 was relatively high, with the last area to increase being the frontal association cortex. Both rCBF and rCMRO2 reached adult values during adolescence. No difference in rCBF was observed between the basal ganglia and the primary cerebral cortex; however, it was prominent in the occipital lobe in every age bracket. No significant changes in rOEF were found during childhood. CONCLUSION: The dynamic changes of rCBF and rCMRO2 observed in children probably reflect the physiologic developmental state within anatomic areas of the brain.

Correlation between choline level measured by proton MR spectroscopy and Ki-67 labeling index in gliomas.

BACKGROUND AND PURPOSE: The clinical relevance of proton MR spectroscopy needs further clarification as to its usefulness and limitations. The purpose of this study was to investigate the correlation between the semiquantitative choline-containing compound level (Cho value) measured by MR spectroscopy and the Ki-67 labeling index in gliomas. METHODS: Localized proton spectra were obtained in 26 consecutive patients with glioma who subsequently underwent surgery for tumor removal. Metabolic values in the spectra were measured semiquantitatively using an external standard of reference. The Ki-67 labeling index was measured in the surgical specimen. Because the semiquantitative metabolic values may be affected by tissue components included in the spectroscopic voxel, the MR imaging appearance of the voxel within the tumor was classed as homogeneous or heterogeneous through visual evaluation of the presence of necrosis, cyst, hemorrhage, and calcification, and pattern of enhancement. RESULTS: We found a strong linear correlation between the Cho value and the Ki-67 labeling index in the 18 homogeneous gliomas, but no correlation was found in the eight heterogeneous gliomas, which turned out to be malignant. CONCLUSION: The semiquantitative Cho value is a reliable predictor of proliferative activity of gliomas when the tumor appears homogeneous on MR images.

Sequential assessment of cerebral blood flow in diffuse brain injury by 123I-iodoamphetamine single-photon emission CT.

PURPOSE: Our goal was to elucidate the temporal profile of cerebral circulation and its relationship to prognosis in patients with diffuse brain injury by using single-photon emission CT (SPECT) and 123I-iodoamphetamine (IMP). METHODS: A total of 67 assessments were made in 26 patients with diffuse brain injury (Glasgow Coma Scale score < or = 8). The microsphere method was used for quantifying cerebral blood flow (CBF). The hemispheric CBF was defined as a mean regional CBF (rCBF), and the total cerebral hemispheric CBF (tCBF) as a mean of the bilateral hemispheric CBF. The relationship between patient outcome and tCBF was investigated. RESULTS: The rCBF in patients with diffuse brain injury showed dynamic and global changes with little regional differences. The tCBF values increased in 1 to 3 days, and they were higher in the poor-outcome group than in the good-outcome group. During the period of 14 to 42 days, the tCBF values stayed within normal range in the good-outcome group, whereas they were below normal range in the poor-outcome group. CONCLUSION: Our results revealed a good correlation between patient outcome and CBF values. Quantitative and sequential CBF studies with IMP SPECT are promising for helping to determine the prognosis for patients with diffuse brain injury.

The relationship between cerebral infarction and angiographic characteristics in childhood moyamoya disease.

BACKGROUND AND PURPOSE: In childhood-onset moyamoya disease, the angiographic disease process of stenoocclusive lesions is progressive, and cerebral infarctions often develop as a result of ischemia. Our purpose was to determine how the severity of stenoocclusive lesions in the anterior and posterior circulations affects the distribution of cerebral infarction in patients with childhood-onset moyamoya disease. METHODS: In 69 patients with childhood-onset moyamoya disease, angiograms were reviewed for stenoocclusive lesions, and CT scans, MR images, or both were reviewed for the sites and extent of cerebral infarction. The relationship between the angiographic and CT/MR findings was examined. RESULTS: The prevalence and degree of stenoocclusive lesions of the posterior cerebral artery (PCA) significantly correlated with the extent of lesions around the terminal portion of the internal carotid artery (ICA). The prevalence of infarction significantly correlated with the degree of stenoocclusive changes of both the ICA and PCA. Infarctions tended to be distributed in the anterior borderzone in less-advanced cases, while in more advanced cases lesions were additionally found posteriorly in the territory of the middle cerebral artery, the posterior borderzone, and the PCA territory. CONCLUSION: Our results indicate that progressive changes of the anterior and posterior circulations are associated with the distribution of cerebral infarction, culminating in a patchily disseminated or honeycomb pattern of infarction on CT and MR studies in late stages of the disease.

Evaluation of tethered cord syndrome associated with anorectal malformations.

The clinical courses of four patients with occult spinal dysraphism who were also found to have anorectal malformations and tethered cord syndrome are evaluated in this report. These patients were among 27 patients with occult spinal dysraphism treated in the Division of Neurosurgery of Tohoku University School of Medicine during the last 3 years. All four patients experienced urinary disturbances early in life, and initially, these disturbances were considered to be caused by urogenital malformations. As a result, treatments were delayed. Only one patient with male Turner's syndrome exhibited mental retardation. Other symptoms, such as sensory disturbance and pain in the lower extremities, became apparent from complaints by the patients without atresia ani. When surgery was performed earlier in our patients with occult spinal dysraphism, the outcome was better. We believe in early surgery for tethered cord syndrome, although there is no consensus for the timing of this surgery. Unfortunately, the diagnosis of tethered cord syndrome was delayed in our four patients. However, because occult spinal dysraphism and anorectal malformations seem to be closely related, the presence of anorectal malformations may result in an earlier diagnosis of tethered cord syndrome.

Thallium-201 single-photon emission computed tomographic and proton magnetic resonance spectroscopic characteristics of intracranial ganglioglioma: three technical case reports.

OBJECTIVE: The correlation between thallium-201 (201TI) uptake, semiquantitative choline-containing compound values measured by proton magnetic resonance spectroscopy (1H-MRS), and Ki-67 labeling indexes (LIs) was investigated in three gangliogliomas. METHODS: The early and delayed 201TI indexes were calculated as the ratio of tumor to normal brain tissue uptake by 201TI single-photon emission computed tomography. Single-voxel 1H-MRS was performed to measure the levels of metabolites in the tumors. Ki-67 LI was measured in the surgical specimens. RESULTS: All three gangliogliomas showed very high 201TI uptake on both early and delayed images. 1H-MRS demonstrated malignancy based on the high choline peak relative to the creatine and N-acetylaspartate peaks. Ki-67 LI was less than 1% in two gangliogliomas and 3.5% in an anaplastic ganglioglioma. CONCLUSION: Both 201TI single-photon emission computed tomography and 1H-MRS indicated malignancy, whereas Ki-67 LI indicated low growth activity. 201TI single-photon emission computed tomography and 1H-MRS of ganglioglioma might be affected by metabolic characteristics other than growth activity.

Value of constructive interference in steady-state three-dimensional, Fourier transformation magnetic resonance imaging for the neuroendoscopic treatment of hydrocephalus and intracranial cysts.

OBJECTIVE: To assess the value of constructive interference in steady-state, three-dimensional, Fourier transformation (CISS) magnetic resonance imaging in the endoscopic management of hydrocephalus and intracranial cysts. METHODS: CISS imaging and T2-weighted imaging were performed for 14 consecutive patients before and after fenestration procedures, using a flexible endoscope, to treat loculated or multiloculated hydrocephalus (4 patients), aqueductal stenosis or obstruction (4 patients), arachnoid cysts (4 patients), a cyst of the velum interpositum (1 patient), or an ependymal cyst (1 patient). Fifteen fenestration procedures were performed, including one reoperation. RESULTS: Preoperative CISS imaging demonstrated intracystic intraventricular septa not observed with conventional T2-weighted imaging for 11 of 15 procedures and provided better brain tissue/cerebrospinal fluid contrast, allowing better understanding of the cause of hydrocephalus and the nature of the cysts. CISS imaging and T2-weighted imaging were equally useful for monitoring postoperative changes in the sizes of ventricles or cysts and the presence of flow voids after third ventriculostomies. However, only CISS imaging clearly demonstrated the site of fenestration for six of the nine patients who underwent fenestration procedures. CONCLUSION: CISS imaging provides excellent cerebrospinal fluid/brain tissue contrast, allowing detailed study of the anatomic features of the ventricular system and cystic lesions. CISS imaging is valuable for both preoperative decision-making and postoperative evaluation.

Effect of mannitol on local cerebral blood flow after temporary complete cerebral ischemia in rats.

The effects of pretreatment with mannitol on local cerebral blood flow (CBF) after permanent or temporary global cerebral ischemia were evaluated with 14C-iodoantipyrine autoradiography in rats under halothane-N2O endotracheal anesthesia. Blood pressure, pulse rate, arterial blood gas levels, and electroencephalographic (EEG) tracings were monitored throughout the experiments. After permanent occlusion of the basilar artery and both external carotid and pterygopalatine arteries, severe global ischemia was induced by permanent occlusion of the common carotid arteries (CCA's) or by a 30-minute temporary CCA occlusion followed by 5 minutes of reperfusion. Intravenous mannitol (25%, 1 gm/kg) or saline solution was administered 5 minutes before occlusion of the CCA's. Cerebral blood flow was measured in 24 anatomical regions. The EEG tracings flattened within 2 to 3 minutes after the onset of ischemia, and no recovery was observed during reperfusion. In the mannitol-treated rats and the saline-treated controls, autoradiographic studies after permanent occlusion showed no CBF in the forebrain or cerebellum, although brain-stem and spinal cord CBF values were normal. After 5 minutes of reperfusion, CBF in the cortex, basal ganglia, and white matter was 100% to 200% higher in mannitol-treated rats and 50% to 100% higher in saline-injected rats than in the nonischemic anesthetized control group. Heterogeneously distributed areas of no-reflow were seen in all saline-injected rats but were observed in none of the mannitol-treated rats. Pretreatment with mannitol prevented postischemic obstruction of the microcirculation during 5 minutes of recirculation after 30 minutes of severe temporary ischemia, but the EEG signals did not recover. Further studies of the functional and morphological responses to longer periods of postischemic recirculation are needed to verify the extent to which these mannitol-induced effects are protective.

Ruptured cerebral pseudoaneurysm caused by the removal of a ventricular catheter. Case report.

A rare case of cerebral pseudoaneurysm located at the internal carotid artery (ICA) was caused by the removal of a ventricular catheter in an infant. This 4-month-old girl underwent ventriculoperitoneal shunt revision, during which the old ventricular catheter was removed from the posterior horn of the left lateral ventricle, but the choroid plexus was pulled out by the tip of the catheter. Intraventricular hemorrhage (IVH) and subarachnoid hemorrhage were observed postoperatively. Magnetic resonance (MR) angiography performed on the 12th postoperative day revealed ICA stenosis and aneurysm formation at the C1 portion of the left ICA. Contrast-enhanced computerized tomography (CT) scans obtained on the 21st postoperative day revealed recurrent IVH and enlargement of the lesion. The patient underwent surgery for treatment of the aneurysm. Operative findings revealed a pseudoaneurysm arising from the left ICA at the proximal end of the anterior choroidal artery (AChA). The aneurysm was removed and the wall of the ICA was reconstructed. Postoperative three-dimensional CT scanning and MR angiography demonstrated disappearance of the aneurysm and preservation of the ICA. The patient was discharged without additional neurological deficits. Many complications, including IVH, are associated with removal of a ventricular catheter. This case shows that pseudoaneurysm formation can occur in a remote region due to avulsion of the AChA from the ICA. In most circumstances a ventricular catheter can be removed without difficulty. However, precision and caution should be exercised when removing a ventricular catheter.

Cerebral circulation and metabolism in the acute stage of subarachnoid hemorrhage.

OBJECT: The mechanism of reduction of cerebral circulation and metabolism in patients in the acute stage of aneurysmal subarachnoid hemorrhage (SAH) has not yet been fully clarified. The goal of this study was to elucidate this mechanism further. METHODS: The authors estimated cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), O2 extraction fraction (OEF), and cerebral blood volume (CBV) preoperatively in eight patients with aneurysmal SAH (one man and seven women, mean age 63.5 years) within 40 hours of onset by using positron emission tomography (PET). The patients' CBF, CMRO2, and CBF/CBV were significantly lower than those in normal control volunteers. However, OEF and CBV did not differ significantly from those in control volunteers. The significant decrease in CBF/CBV, which indicates reduced cerebral perfusion pressure, was believed to be caused by impaired cerebral circulation due to elevated intracranial pressure (ICP) after rupture of the aneurysm. In two of the eight patients, uncoupling between CBF and CMRO2 was shown, strongly suggesting the presence of cerebral ischemia. CONCLUSIONS: The initial reduction in CBF due to elevated ICP, followed by reduction in CMRO, at the time of aneurysm rupture may play a role in the disturbance of CBF and cerebral metabolism in the acute stage of aneurysmal SAH.

Surgical treatment of posterior fossa tumors via the occipital transtentorial approach: evaluation of operative safety and results in 14 patients with anterosuperior cerebellar tumors.

OBJECT: To determine the safety and usefulness of performing surgery via the occipital transtentorial approach to treat anterosuperior cerebellar tumors, evaluation of 14 patients was performed over a 5-year period. METHODS: The study was performed in 14 patients, aged 6 months to 71 years, who harbored anterosuperior cerebellar tumors of the posterior fossa including four hemangioblastomas, three cerebellar astrocytomas, three medulloblastomas, two metastatic tumors, one recurrent astrocytoma, and one rhabdoid cell tumor. All patients underwent surgical treatment by the same surgical team and via the same surgical approach. Endoscopy combined with neuronavigation was used for large, deep-seated tumors extending to the fourth ventricle. Of the 14 patients, total or gross-total removal was achieved in 12 patients and subtotal removal in two patients. There was no incidence of mortality or morbidity in the 14 patients, and all functional outcomes were good to excellent postoperatively. Postoperative magnetic resonance imaging revealed that none of the patients had suffered brain damage or infarction around the cerebellum, brainstem, or occipital lobe. CONCLUSIONS: Although this study was the first in which a specific examination of the efficacy of the occipital transtentorial approach in patients with anterosuperior cerebellar tumors was undertaken, our findings suggest that this surgical approach is very useful, safe, and accurate for removing the primary tumor and evaluating the surrounding anatomy, as well as for determining operative strategy.

Congenital primary cerebral angiosarcoma. Case report.

Reports of angiosarcoma arising in the central nervous system are rare. The authors present the case of a 30-day-old infant with clinical manifestations of projectile vomiting and tense anterior fontanelle resulting from a left frontotemporal tumor. Total excision of this highly vascular, well-circumscribed tumor was performed without incident, and histopathological examination revealed a malignant angiosarcoma. Immunohistochemical reaction of the neoplastic cells was diffusely positive for endothelium-specific antigens including factor VIII-related antigen, CD31, and CD34. The final diagnosis of congenital primary cerebral angiosarcoma was thus confirmed. The patient's postoperative course was uneventful, and he was discharged 2 weeks after the operation. He was in good condition with no sign of recurrence after 11 months; follow-up computerized tomography, magnetic resonance (MR) imaging, and abdominal ultrasonography studies demonstrated no tumor regrowth. The characteristic findings for this tumor on MR imaging, the immunohistochemical findings, and surgical outcome are discussed.

Effect of inhalational anesthesia on cerebral circulation in Moyamoya disease.

To clarify the effects of inhalational anesthesia on cerebral circulation in patients with Moyamoya disease, the authors measured regional cortical blood flow (CoBF), jugular bulb oxygen saturation (SjO2), and frontal regional oxygen saturation (rSO2) by near infra-red spectroscopy under total intravenous and inhalational anesthesia in 13 patients undergoing revascularization procedures. Cortical blood flow decreased in some regions under inhaled anesthesia in all cases, and the mean value decreased significantly (p<0.01). Patients' SjO2 levels rose during inhalational anesthesia in 10 of 11 cases (p<0.01). Frontal rSO2 declined in 9 of 11 cases. Regional CoBF levels may be decreased by inhaled anesthesia in patients with Moyamoya disease, and such anesthesia may provoke intracerebral steal. Total intravenous anesthesia, however, lacked these effects.

A case of adult moyamoya disease showing progressive angiopathy on cerebral angiography.

In moyamoya disease, progression of carotid occlusive lesion in an adult patient is very rare. We report a case of adult moyamoya disease with acute angiographical stage progression and hemodynamic deterioration. A 56-year-old female complaining of left motor weakness visited our department. On MRI, infarct lesion was found in the right white matter. On cerebral angiography, occlusive lesions in the bilateral internal carotid arterial siphons and moyamoya vessels were found. The right side was stage V and the left side was stage III. On IMP-SPECT, decreased cerebral hemodynamic reserve of the right cerebral hemisphere was found. In this patient, right STA-MCA anastomosis was performed. After operation, she became possible to walk and discharged to home. Five months after operation, good collateral formation and improvement of hemodynamic reserve in the right hemisphere were found. However, on left carotid arteriography, the anterior and middle cerebral arteries were only slightly imaged, and the disease state progressed to stage IV. In addition, decreased blood flow and hemodynamic reserve were appeared in the left hemisphere.

Assessment of encephalo-galeo-myo-synangiosis with dural pedicle insertion in childhood moyamoya disease: characteristics of cerebral blood flow and oxygen metabolism.

In the surgical treatment of childhood Moyamoya disease, we have been performing a new non-anastomotic bypass surgery using encephalo-galeo-myo-synangiosis (EGMS) with dural pedicle insertion over the brain surface. To assess the results obtained using this procedure, the long-term clinical outcome and the characteristics of cerebral blood flow and oxygen metabolism using PET were evaluated. The subjects were 19 patients with childhood Moyamoya disease admitted to our institution over 8 years from 1988 to 1996. This type of surgery was performed 39 times and the patients have been followed up from 10 months to 8 years. Preoperatively, although cerebral blood flow and oxygen metabolism were varied from individual to individual, low values of regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of oxygen (rCMRO2) with relatively high values of regional oxygen extraction fraction (rOEF) were found in the frontal region in most of the patients compared to normal children. Postoperatively, obvious improvement of cerebral blood flow and hemodynamics in all the areas in the operative site and clinical symptoms and signs ameliorated or disappeared during the follow-up period. In conclusion, the present method appeared to be useful to improve the hemodynamic in the brain and its long-term clinical outcome was satisfactory.

Proton magnetic resonance spectroscopy in children with moyamoya disease.

Proton magnetic resonance spectroscopy (MRS) is an effective method to noninvasively investigate cerebral metabolism. The aim of this study was to evaluate cerebral metabolic changes in children with Moyamoya disease using proton MRS. A total of 11 patients under 15 years old were enrolled, whose main symptoms were transient ischemic attacks. In nine patients, the more and less affected hemispheres could be determined according to their symptoms and/or single-photon emission computed tomography (SPECT). A single voxel point resolved spectroscopy was performed in the frontal or parietal white matter bilaterally by using 1.5 Tesla MR system (repetition time 2000 ms and echo time 272 ms). Voxels were located within areas that were normal on T1- and T2-weighted MR imaging. Choline (Cho), creatine (Cre) and N-acetyl aspartate (NAA) were semiquantitated as a metabolite value using an external standard reference. Pre-operative Cho, Cre and NAA values were within respective normal ranges. No metabolite showed a significant difference between the more and less affected hemispheres. A total of six patients were examined before and after revascularization surgery on one side. Pre- and post-operative comparisons demonstrated that all three metabolites showed statistically significant increases following surgery. These results suggest that, although the mechanism of spectroscopic changes needs to be further investigated, proton MRS provides a valuable method to evaluate cerebral metabolism in children with Moyamoya disease.

Repositioning of the tortuous vertebrobasilar artery for trigeminal neuralgia: a technical note.

A patient with trigeminal neuralgia caused by a tortuous vertebrobasilar artery is reported. To obtain safe and certain neurovascular decompression of the trigeminal nerve, the tortuous vertebrobasilar artery was repositioned by pulling it toward the dura mater of the clivus using a synthetic vascular slip. The authors describe the technique of repositioning of the tortuous vertebrobasilar artery and its usefulness.

Evaluation of neuronal loss in adult moyamoya disease by 123I-iomazenil SPECT.

BACKGROUND: Central benzodiazepine (BZD) receptor imaging is effective to evaluate neuron density in the pathological brain cortex. This study used BZD receptor imaging to evaluate neuronal damage in adult ischemic moyamoya disease. METHODS: Single photon emission computed tomography and a novel tracer, 123I-iomazenil, were used to measure BZD receptor density in the brain. Evaluation of early and late images was performed in three asymptomatic, unoperated patients, and six mildly symptomatic, operated patients. RESULTS: Uptakes in the frontal, parietal, and occipital lobes of symptomatic patients were significantly lower (p<0.05) than those of asymptomatic patients. The late image/ early image count ratios (L/E ratios) of asymptomatic patients were relatively constant (mean, 0.571; range, 0.550-0.581) in all regions of interest. In contrast, the L/E ratios of symptomatic patients were not uniform. CONCLUSIONS: The neuron density was preserved in adult asymptomatic patients despite harboring moyamoya disease. In contrast, the neuronal density was decreased in symptomatic patients even though their symptoms were mild and they had undergone revascularization.