Takashi Shibasaki

Assessment of malignancy of glioma by positron emission tomography with 18F-fluorodeoxyglucose and single photon emission computed tomography with thallium-201 chloride

Abstract The histological diagnosis and proliferative potential measured by bromodeoxyuridine (BrdU) labelling index (LI) were corelated with preoperative CT and contrast-enhanced, MRI, 18F-flurodeoxyglucose positron emission tomography (PET) and 201T1 single photon emission computed tomography (SPECT) in 43 patients with various grades of glioma. 201T1 SPECT had slightly higher sensitivity to tumours with BrdU LI N 5 % (showing 10/10) than 18F-FDG PET (7/8 tumours). 18F-FDG PET was better for identifying tumours of BrdU LI < 1 % (13/15) than 201T1 SPECT (13/22). Accumulation of 201T1 in the tumour was slightly different from contrast enhancement on CT and/or MRI, and gave “false-postive” results in some low-grade gliomas. However, 201T1 SPECT, which is available in many hospitals and may cost less, provided useful information to supplement that from CT and MRI.

General activation of cerebral metabolism with speech: a PET study

We report the pattern of metabolic activation of the brain associated with speech, using 15O positron emission tomography (PET) in normal volunteers, as well as patients with or without language deficit. 15 trials were performed on 13 subjects. Regional oxygen metabolism with the subjects at rest was compared to that during a speech-from-memory task. As expected, there was strong activation of Brocas area and the medial left temporal lobe, corresponding to the motor speech and memory aspects of the task. In addition, both cerebellar hemispheres and pre-motor areas, as well as the right frontal operculum, supplementary motor area and right parietal lobe were active. This technique provided insight into the mechanism of aphasia in two subjects, even in one whose traditional language areas were structurally and metabolically intact at rest. We conclude that this practical activation technique may be useful not only in studying the physiology of normal brain, but also in understanding functional responses to disease.

Long-term observations in cases with spontaneous carotid-cavernous fistulas

Twenty-six cases with spontaneous carotid-cavernous fistulas were followed up for periods ranging between 4 months and 9 years 8 months. A complete regression of symptoms without reappearance for more than 6 months was noted in 19 cases, a marked improvement in 2 cases, and a moderate regression in 3 cases. In 2 cases, symptoms have continued for 9 years 8 months and for 1 year. The regression of symptoms was usually delayed in patients less than 60 years old, in cases in which the symptoms developed slowly, and in cases with multiple draining veins. According to our observations a regression of symptoms may occur after very slight changes of haemodynamics. Compression of the cervical carotid artery for a short time or a temporary occlusion of the carotid artery by a balloon catheter should be considered as the treatment of choice in the first instance in cases with spontaneous carotid-cavernous fistulas showing relatively low pressure and low flow shunt.

Composition of free amino acids in brain tumors

The composition of the free amino acid pools in various brain tumors and in normal brains obtained at surgery or at autopsy is determined with an automatic amino acid analyzer and the results statistically evaluated. The tumors have lower ratios of GABA in the pools than the normal brain; tumors with higher GABA ratios are found in those which are in close contact with and have an invasive nature to brain tissue. In gliomas, the more malignant a tumor becomes, the more different the composition in that tumor is from that in normal brain tissue. But conversely, the ratio of GABA is highest in glioblastoma. The composition of the pool in oligodendroglioma is not significantly different from that in the normal brain. Metastatic brain tumors show the highest ratios of phenylalanine, tyrosine and methionine in the pool among the tumors and the normal brain. From the viewpoint of the composition of the free amino acid pools, like from that of the histological aspects, brain tumors seem to be classified into four groups: glioma, neurinoma, meningioma and metastatic tumors.

Concentrations of sulfur-containing free amino acids in lumbar cerebrospinal fluid from patients with consciousness disturbances

ABSTRACT The concentrations of sulfur‐containing amino acids (taurine, methionine, cystine, cystathionine, homocystine) in lumbar CSF from patients with consciousness disturbances and controls were measured, and it was investigated whether there was any correlation between the sequential changes of these amino acid concentrations and of the level of consciousness. In all patients, thyrotropin‐releasing hormone (TRH) was administered and the changes of levels of consciousness and amino acid concentrations were followed before and after administration. The concentrations of taurine and cystathionine from the patients were significantly lower, and methionine and cystine significantly higher than those from the controls; they returned to the control values in parallel with improvement of consciousness level. Homocystine was not detected in either patients or controls. These results suggest that the alteration in the level of consciousness is associated with distortion of sulfur‐containing amino acid metabolism within the central nervous system, at least in the CSF.

Primary Ewing’s sarcoma of the orbit: case report

A 22-year-old man presented with tenderness and swelling of the left lateral part of the orbit. Computed tomography revealed a left intraorbital mass measuring 3 cm × 3 cm involving the left lateral wall of the orbit and the greater wing of the left sphenoid bone. Magnetic resonance imaging revealed that the intraorbital mass was extraneuroaxial. During surgery, the tumor was seen to arise from the lateral wall of the orbit and infiltrate into the left temporal muscle. Following the surgery, the patient was administered radiation therapy for the whole cranium and chemotherapy for the residual tumors. However, the tumor recurred, and the patient died about 2 years following the first surgery because the tumor had metastasized to the lung. On light microscopy, the tumor cells were closely packed with uniform, small, and round cells. Immunohistochemical studies showed that the tumor cell membrane stained positive for MIC2. Furthermore, the MIB-1 labeling index was 36.2%. On electron microscopy, small quantities of cytoplasm containing glycogen accumulations without neurosecretory granules and neurofilaments were observed. Based on these results, the tumor was diagnosed to be primary Ewing’s sarcoma. Primary orbital Ewing’s sarcoma of the skull has been considered to be extremely rare, and a review of the literature was performed.

Positron emission tomography with 4-[18F]fluoro-L-m-tyrosine in MPTP-induced hemiparkinsonian monkeys

PET imaging studies with 4-[18F]fluoro-L-m-tyrosine (FMT) in normal macaca monkeys showed selective accumulations of radioactivity in the striatum with time. In monkeys rendered hemiparkinsonian by intracarotid infusion of l-methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP), FMT uptake was eliminated in the lesioned striatum. FMT-PET studies were able to detect dopaminergic terminals in both normal and hemiparkinsonian monkeys, and clearly showed a reduction in aromatic L-amino acid decarboxylase (AAAD) activities in the MPTP-lesioned striatum. These results show that FMT is promising as a PET tracer for the evaluation of central dopaminergic systems in parkinsonism.

Study on the Function of the Basal Ganglia and Frontal Cortex Using Depth Micro-recording and PET Scan in Relation to the Outcome of Pallidotomy for the Treatment of Rigid-Akinesia-Type Parkinson's Disease

Stereotactic posteroventral pallidotomy was carried out in 13 cases with rigid-akinesia-type Parkinsons disease with the aid of depth microrecording. The outcome of the pallidotomy was classified into four groups: excellent (6 cases), good (3 cases), moderate (3 cases) and fair (1 case). Electrophysiological study during the operation showed continuous high-frequency and high-amplitude spike discharges in the globus pallidus (GPi) in the excellent-response group. Before the operation, a PET study had revealed low regional cerebral glucose metabolism in the prefrontal area in all the patients. Unilateral sequential opposite finger movement induced less increase of regional cerebral blood flow both in the supplementary and primary motor area in the less effective-response groups. The indications of pallidotomy for the treatment of rigid-akinesia-type Parkinsons disease are discussed.

Calcified astrocytoma of the amygdalo-hippocampal region in children.

Three pediatric cases of temporal lobe seizure due to calcified glioma of amygdalo-hippocampal region are described. Computed tomography and magnetic resonance imaging showed dense calcification with no postcontrast enhancement in the amygdalo-hippocampal region. Positron emission tomography showed low oxygen metabolism, low glucose metabolism, hypermetabolism of amino acids, and low regional cerebral blood flow in the tumors. Single photon emission computed tomography showed a high accumulation of201Tl chloride and123I-isopropyl iodoamphetamine in one tumor, but otherwise low radioisotope uptake. These studies indicated lowgrade malignancies. The patients were treated by partial tumor removal and radiotherapy. Histological examination of the tumor specimens showed astrocytoma with interstitial calcification. One patient died due to tumor recurrence, while the others are doing well with minimal seizure. We recommended temporal lobectomy in similar cases to achieve complete remission.

Neural Activity of the Basal Ganglia in Parkinson’s Disease Studied by Depth Recording and Pet Scan

The basal ganglia is certainly one of the major centers of the central nervous system controlling voluntary movement and posture1, but its precise role is still far from understanding. Only experimental studies in monkeys with various conditioned voluntary movements or with experimentally produced involuntary movements were carried out to observe neural activities of the basal ganglia associated with these particular conditions.