Tadao Kawamura

Cerebral abnormalities in lumbosacral neural tube closure defect: MR imaging evaluation

Abstract. Objects: It was decided that patients with caudal neural tube closure defect should be evaluated by means of cranial MR scans, with special attention devoted to cerebral malformations other than craniospinal abnormalities. Methods: Twenty-four patients with lumbosacral neural tube closure defects, classified into myeloschisis (MS, 9 cases), meningo(myelo)cele (MMC, 10 cases) and spina bifida occulta with lumbosacral lipoma (LL, 5 cases), were evaluated in this way, and cerebral anomalies were found to be present in all MS patients, 8 with MMC and 2 with LL. The cerebral hemispheres were mildly to moderately hypoplastic in 6 patients, and hydrocephalus was present in 6 patients with MS and in 5 with MMC; LL was not associated with ventriculomegaly in any patient. Polymicrogyria was present in 6 patients with MS, in 3 with MMC, and in none of those with LL. Heterotopic gray matter was observed in only 2 patients with MS. Partial agenesis of the corpus callosum was found in 6 MS patients and in 6 patients with MMC, but was not seen in patients with LL. Cervicomedullary anomalies, such as herniation of the cerebellar tonsils through the foramen magnum, were found in 7 patients with MS, in 4 with MMC and in 2 with LL. While patients with LL were accompanied by only mild forebrain anomalies, cerebral abnormalities in MS and MMC were generally more severe in degree than those in LL. Among 21 patients in whom intellectual and performance status was evaluated, 9 of the 17 patients with cerebral anomalies had some degree of retardation, and the 4 without cerebral anomalies were normal. Conclusions: Caudal neural tube closure defect is not a single developmental abnormality, and can be regarded as one part of the spectrum of malformations causing primary insults that are as yet unidentified to the developing central nervous system.

Corpora Amylacea Replace the Hippocampal Pyramidal Cell Layer in a Patient with Temporal Lobe Epilepsy

Summary: A 39‐year‐old woman, with a 23‐year history of medically intractable seizures of the complex partial type, underwent a left anterior temporal lobectomy and hippocampectomy. Histologic examinations revealed a massive occurrence of corpora amylacea, neuronal loss, and gliosis in the pyramidal cell layer of the hippocampus. The distribution of corpora amylacea in this case was quite distinctive and unlike the patterns of “nonspecific” corpora amylacea formation seen in aging or other neurodegenerative conditions. The pathogenetic aspects of the accumulation of these peculiar bodies are discussed in relation to hippocampal sclerosis.

Thalamic hypometabolism on 18FDG-positron emission tomography in medial temporal lobe epilepsy

Abstract Objectives: Degree of hypometabolism in the thalamus on 18Fluorodeoxyglucose-positron emission tomography (FDG-PET) was compared with those of medial and lateral temporal lobes in patients with medial temporal lobe epilepsy (mTLE), and its relationship with post-operative seizure outcomes was investigated. Methods: Twenty-six patients with mTLE who underwent anterior temporal lobectomy were included. Post-operatively, 13 patients became completely seizure-free and 13 showed residual seizure, regardless of frequency (five patients became almost seizure-free, six had rare seizures and two showed significant improvements). Degrees of hypometabolism in bilateral thalamus, ipsilateral medial and lateral temporal lobes were evaluated visually and semi-quantitatively by determining the asymmetry index (AI), a value indicating 100 × (ipsilateral - contralateral)/[1/2 × (ipsilateral + contralateral)] and the region-to-cerebral hemisphere ratio (R/C ratio) being the ratio between averaged counts in each area and those in the cerebral hemisphere of the same side. Results: Hypometabolism in the medial temporal lobe was visually observed in all patients. Hypometabolism in the lateral temporal lobe was observed in 20 patients and was semi-quantitatively more prominent than that of the medial temporal lobe. Pathologically, hippocampal sclerosis and prominent astrogliosis of the lateral temporal lobe were present in all cases. However, while thalamic hypometabolism was visually observed in nine patients (in the ipsilateral side of four cases, contralateral side of three and on both sides of two), no significant thalamic hypometabolism was semi-quantitatively observed. No significant differences in metabolic rate in any area except for the lateral temporal lobe between seizure-free patients and residual seizure patients were seen semi-quantitatively. Discussion: Data indicated that metabolism in the lateral temporal lobe of patients with mTLE significantly decreased and revealed pathologic glial changes. Thalamic hypometabolism was quite mild and did not correlate with post-operative seizure outcome.

Callosal anomalies in patients with spinal dysraphism: Correlation of clinical and neuroimaging features with hemispheric abnormalities

Abstract Dysgenesis of the corpus callosum can occur in association with spinal dysraphic lesions. Clinical and neuroimaging features were reviewed in 23 patients (12 male, 11 female; mean age 11.3 years) with caudal spinal dysraphism (myeloschisis in eight, meningomyelocele in 10, and lumbosacral lipoma in five) to characterize types and degrees of callosal and other cerebral anomalies. T1- and T2-weighted magnetic resonance images were obtained, and the total midsagittal cross-sectional area of the corpus callosum was determined. The corpus callosum appeared normal in nine patients and was abnormal in 14. In five patients the corpus callosum was narrow, with all regions present; the cerebral hemispheres were hypoplastic. Two patients with dysgenesis of frontal, parietal, and occipital lobes had a small, partly agenetic corpus callosum. In the remaining seven patients the posterior third of the corpus callosum was absent or hypoplastic; six of them had ventriculomegaly that selectively affected the occipital horns (colpocephaly). All callosal anomalies were accompanied by hemispheric ones. This supports a disordered developmental relationship between the corpus callosum and the hemispheres as a cause. Spinal dysraphism can no longer be considered a single developmental abnormality, given the frequent association of other defects. [Neurol Res 2002; 24: 463-467]

Epilepsy in patients with spina bifida in the lumbosacral region

This study aimed to assess the relevance of epilepsy and spina bifida in the lumbosacral region. We evaluated 75 patients with spina bifida admitted to the Kyushu University Hospital from 1980 to 2004. Patients were classified as having meningocele (MC, 4 cases), myelomeningocele (MMC, 6), myeloschisis (MS, 45), and lumbosacral lipoma (LL, 20). Nine cases had epileptic disorders, and all showed MS. Meticulous neuroradiological investigations revealed cerebral abnormalities such as polymicrogyria or hypogenesis of the corpus callosum in all epileptic cases. Locations of cerebral abnormalities topographically correlated with areas of interictal EEG abnormalities. Although all epileptic cases had ventriculoperitoneal (VP) shunt for hydrocephalus before the onset of epilepsy, interictal EEG abnormalities could not be explained by location of the VP shunt. In all LL patients, neither history of epilepsy nor cerebral abnormalities were noted on magnetic resonance imaging (MRI). Epileptogenesis in spina bifida patients seemed to correlate with coexisting cerebral abnormalities in MS patients rather than with the VP shunt. However, not all spina bifida patients associated with cerebral abnormalities had epilepsy, and not all cerebral abnormalities were epileptogenic, suggesting that epilepsy in spina bifida patients was multifactorial.

Relationship between regional cerebral blood flow and electrocorticographic activities under sevoflurane and isoflurane anesthesia

The aims of this study are (1) to assess the effects of volatile anesthetics on regional cerebral blood flow (rCBF) and electrocorticography (ECoG), and (2) to investigate the relationship between rCBF and ECoG influenced by volatile anesthetics. The authors measured rCBF using laser Doppler flowmetry and ECoG simultaneously and continuously from the same cortex during craniotomy, using the specially arranged probe. Patients received intravenous anesthetics with nitrous oxide until craniotomy, and after opening of dura, volatile anesthetic, either isoflurane or sevoflurane, was started and was gradually increased for the measurement. Four of the nine cases (44.4%) of the sevoflurane group showed no change both in rCBF and ECoG. In three cases (33.3%), rCBF increased as the frequency of the paroxysmal activities increased. In two cases (22.2%), decreased rCBF was accompanied by slow waves. In 12 cases of the isoflurane group, no apparent rCBF and ECoG changes were seen, except a case with decreased rCBF and slow waves. This is the first report of simultaneous recordings of regional CBF and neuronal activity under general anesthesia. During sevoflurane and isoflurane anesthesia <2.5 minimum alveolar anesthetic concentration, rCBF is affected by ECoG activities rather than pharmacologic action of inhalational anesthetics.

Temporal lobe epilepsy and corpora amylacea in the hippocampus: Clinicopathologic correlation

Abstract Corpora amylacea (CoA) have been found in about 60% of neurosurgical specimens showing hippocampal sclerosis (HS). To determine clinical and neuroimaging differences between HS with and without CoA, we studied 29 patients (21 male, 8 female; age at surgery, 12 to 49 years0 who underwent anterior temporal lobectomy for intractable medical temporal lobe epilepsy. No CoA were noted in the hippocampus of 11 cases, and deposition of CoA was mild and limited to the subependymal and vestigial hippocampal sulcus regions in nine cases; in nine cases, moderate to marked deposition was noted in the pyramidal cell layer, accompanying severe neuronal loss. No significant differences were evident between these three groups for age at onset, frequency and duration of epileptic seizures, the average age at surgery, or surgical results. Hippocampal hyperintensity in fluid-attenuated inversion recovery magnetic resonance images tended to increase with increasing hippocampal deposition of CoA. Formation of CoA appears to be a response to neuronal loss in the pyramidal cell layer, being related to the epileptogenic process as a consequence rather than a cause. [Neurol Res 2002; 24: 563-369]

Primary Ki-1 lymphoma in the central nervous system

Large cell anaplastic malignant lymphoma with Ki-1 (CD30) antigen is a new entity among human non-Hodgkins malignant lymphomas according Updated Kiel Classification and is also a very rare subtype in primary central nervous system (CNS) malignant lymphomas. The precise clinical characteristics and the significance of Ki-1 antigen have yet to be clarified. The authors herein report a case of Ki-1 positive primary T-cell CNS malignant lymphoma. A 49-year-old man presented with multiple mass lesions in the brain on MRI. Immunohistochemical investigations of biopsy specimens from the superior medullary velum revealed a large cell anaplastic T-cell lymphoma positive for Ki-1 antigen. After administering extensive chemo-radiotherapy, the patient has survived for more than 42 months after the onset of symptoms.

Temporal lobe epilepsy associated with hippocampal sclerosis and a contralateral middle fossa arachnoid cyst

We report on a 13-year-old boy with temporal lobe epilepsy associated with left hippocampal sclerosis and a contralateral arachnoid cyst in the middle cranial fossa (ACMCF). Chronic intracranial recording from subdural grid electrodes showed the left medial temporal lobe to be the ictal onset zone. After left anterior temporal lobectomy with hippocampectomy, seizure control was improved. ACMCF was not considered the direct cause of epilepsy; instead the seizures were attributed to hippocampal sclerosis.

Resolving obstructive hydrocephalus from AVM

Obstructive hydrocephalus with deterioration of consciousness from a ruptured arteriovenous malformation (AVM) requires urgent decompression, but also vigilance during the preoperative stage in case of rare spontaneous resolution.