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Biomedical subjects

T Okudera

Publications and source records attributed to T Okudera.

At least 73 records · Page 4Linked to original sources
PubMed1992

[A method for measurement of regional cerebral blood flow using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) SPECT; two scans with one point blood sampling technique].

We have developed a new method to quantitate regional cerebral blood flow (CBF) using 123I-IMP and SPECT. This technique requires two SPECT scans and one blood sampling. Based on the 2 compartment model (influx; k1 and outflux; k2), a table between k2 and ratio of 1st scan counts/2nd scan counts was calculated, and a table look up procedure yielded a unique pair of k1 (CBF) and distribution volume (Vd = k1/k2) for each region of interest (ROI). The arterial input function was obtained by one point blood sampling to calibrate the standard input function, which has been obtained from the previous study on 12 subjects. This method was applied to 5 subjects including 1 healthy volunteer and 4 patients with cerebral infarction, and the regional CBF results were compared with those measured by H2(15)O PET technique. Optimized scan time combination was 40, 180 min which provided the best correlation with H2(15)O-CBF. The Vd values obtained in infarcted regions were significantly smaller than those in normal regions, suggesting the importance of measuring Vd for each ROI.

Aged↗
PubMed1992

Cerebral blood flow and glucose metabolism measurements in a patient surviving one year after carbon monoxide intoxication.

A 29-yr-old woman was studied for 1 yr after acute carbon monoxide intoxication following an attempted suicide by inhalation of automobile exhaust fumes. The patient demonstrated impaired responsiveness to stimuli without any specific neurological deficits for 1 yr after carbon monoxide intoxication. Repeated brain magnetic resonance imaging consistently displayed only bilateral globus pallidus lesions, but no lesions in either deep white matter or cerebral cortex. Position emission tomography measurements of regional cerebral blood flow, and glucose utilization rate were made in this patient at 6 mo and 1 yr following carbon monoxide intoxication. Impairment of both blood flow and glucose metabolism were found not only in the basal ganglia but also in morphologically normal frontal cortex. The decrease in glucose utilization in the frontal cortex was greater than that in the basal ganglia. During the period of 6 mo to 1 yr, blood flow and glucose metabolism in the basal ganglia recovered to the normal range. In the frontal cortex, however, blood flow and glucose metabolism remained approximately 20% lower than the normal mean values. This prolonged dysfunction in the frontal cortex may therefore be responsible for the impaired responsiveness of the subject.

Adult↗
PubMed1991

MR imaging of birth brachial palsy in a two-month-old infant.

A female baby at two months old was diagnosed as having birth branchial palsy and was studied by magnetic resonance imaging (MRI) which is a non-invasive and safe method for assessing any brachial plexus injury in the infant. A traumatic meningocele involving a root avulsion injury was clearly demonstrated by the MRI findings.

Birth Injuries↗
PubMed1991

Surgical intervention for a giant aneurysm of the vertebral artery--case report.

A radical operation in an elderly man with a giant aneurysm of the vertebral artery was successfully performed. The aneurysm in the posterior fossa caused symptoms such as a disturbance of the lower cranial nerves, as well as pyramidal and cerebellar signs. An aneurysmectomy was performed for decompression of the brain stem and cranial nerves. An extended lateral suboccipital approach was chosen which made it possible to remove the rim of the foramen magnum and reach the condylar fossa. This approach also made access to the vertebro-basilar junction possible for trapping. After resection of the aneurysm and thrombectomy (endaneurysmal microendarterectomy), the aneurysmal neck as well as its clipping was closed, and consequently its parent artery. The procedure is described in this report.

Humans↗
PubMed1991

Microvasculature in germinal matrix layer: its relationship to germinal matrix hemorrhage.

Microvasculature in the germinal matrix layer (GML) was studied by postmortem microangiography and stereomicroscopic observation on cleared specimens in methyl salicylate. A number of arterioles from penetrating and medullary branches of main cerebral arteries were distributed in the GML, forming a fine network of arterioles anastomosing with each other. Many venules in the GML converged at a few points and drained into subependymal veins. The main converging zone of venules was situated inside the GML close to the border zone of the GML and adjacent cerebral parenchyma. The converging zone coincided with the site of GML hemorrhage. Thus, many factors, including both venous and arterial, appear to influence circulation in the GML; ultimately the converging zones become overloaded and rupture, leading to GML hemorrhage.

Angiography↗
PubMed1990

A follow-up study by CT and MRI in 3 cases of Japanese encephalitis.

A follow-up study by CT and MRI in 3 cases of Japanese encephalitis (JE) was performed. Neurologically dementia, forced laughing, tetraplegia and parkinsonism were observed as sequelae. In the CT and MR scans about 3 years after the onset of JE, low-density areas (LDAs) or abnormal signal intensities had remained in the thalamus and basal ganglia. The abnormalities were also found in the brain stem. When the main lesions shown by CT and MRI were compared with those of the acute stage, T2-weighted MRI clearly revealed multiple small areas with high signal intensities, although those in the acute stage had shown diffuse abnormal signals. These findings may be useful in helping to identify JE a long time after the onset.

Brain↗
PubMed1990

Germinal matrix hemorrhage of venous origin in preterm neonates.

The rupture point of germinal matrix hemorrhage in premature neonates was examined by postmortem angiography. Thirteen cases of germinal matrix hemorrhage were injected via artery (four cases), vein (five cases), and both artery and vein simultaneously (four cases). Only material injected via vein leaked into the hemorrhage, which was confirmed by stereomicroscopic and histologic examination. This study suggests that germinal matrix hemorrhage is venous in origin.

Angiography↗
PubMed1990

Neuroradiological and pathological studies on neonatal aneurysmal dilation of the vein of Galen.

Neuroradiologic and neuropathologic findings on neonatal aneurysmal dilation of the vein of Galen are reported. Doppler echocardiography revealed a diastolic reversed Doppler signal, which suggested the presence of a cerebral arteriovenous fistula. Cerebral ultrasonography with intravenous injection of contrast medium was useful in the diagnosis. Digital subtraction cerebral angiography clearly demonstrated both the feeding and draining vessels and the aneurysmal dilation of the vein of Galen, although it failed to detect the abnormal vascular channels. Pathologic and histopathologic findings demonstrated intimal thickening of the abnormal vascular channels, which could produce higher vascular resistance and result in the detection failure with digital subtraction angiography.

Cerebral Veins↗
PubMed1990

A statistical study of autopsied cases of neonatal intraventricular hemorrhage.

We have performed a statistical study of 1218 autopsies of neonates to extract the factors related to fatal neonatal intraventricular hemorrhage (IVH). Prematurity indicated by a short gestational period or a low birth weight was the most significant factor for IVH. Many other factors considered to be related to IVH were also related closely to prematurity. Therefore, we pose the following question throughout the study: Did the factors independently relate to IVH without any confounding effects of prematurity? To obtain the answer, we tried a statistical adjustment for gestational age to eliminate the confounding effects of prematurity. After the adjustment was made, we concluded that the following 10 items, in order, were the actual factors related to fatal IVH: prematurity, subependymal hemorrhage, subarachnoidal hemorrhage, respiratory distress syndrome, hyaline membrane disease, respiratory acidosis, intracerebral hemorrhage, cyanosis, respirator care, and low Apgar score. There were two distinctive categories in the factors that were eliminated by the adjustment. One was a group that has no significance whatsoever in any subdivided gestational groups, such as meconium aspiration syndrome, due to purely the result of the confounding effect. The other was a group that showed its statistical significance only in a certain period of gestation, such as breech presentation.

Autopsy↗
PubMed1989

Japanese encephalitis in the Kurume region of Japan: CT and MRI findings.

Neurological, computed tomography (CT) and magnetic resonance imaging (MRI) findings were recorded from 13 patients with Japanese encephalitis (JE) in the Kurume region diagnosed by serological criteria. The patients averaged 63 years of age, and 5 were older than 70 years. The serological data mostly indicated a primary response. Hemiplegia and tetraplegia were common, together with extrapyramidal signs. A few cases had a stroke-like onset and cerebral haemorrhage during the course of JE. CT and MRI in 7 cases revealed abnormalities in the thalamus and basal ganglia including the putamen. The CT and MRI findings from the acute stage to the convalescent stage were considered to be characteristic of JE.

Aged↗
PubMed1989

[Cerebral ischemia and hemorrhage; computed tomography and angiography].

Neuroradiological characteristics of cerebral embolism and hemorrhage were discussed on computed tomography (CT) and angiography. Clinically, cardiogenic embolism was one of major problems in cerebral embolism. On CT, size of the ischemic region, mass effect and frequency of hemorrhagic infarct were most prominent in cerebral embolism. It is difficult to diagnose cerebral infarction within 6 hours of their onset on CT findings. The following signs by Tomura would be important criteria for identifying embolic infarction in the middle cerebral and internal carotid arteries: (a) obscured outline or partial disappearance of the lentiform nucleus, (b) slight decrease in tissue density, (c) effacement of the cortical sulci. Angiographic characteristics of embolism and thrombosis were discussed in terms of shape and configuration at the stump of the occluded arteries, formation of collateral pathway and recanalization. Cerebral hemorrhage were also compared between pathological and CT findings. Indication of cerebral angiography to patients of cerebrovascular disease was also discussed.

Adult↗
PubMed1988

[A case of colloid cyst of the third ventricle].

Colloid cysts of the third ventricle are rare, accounting for less than 1% of all intracranial neoplasms. However, its incidence will increase with increased use of CT scan and MRI. The symptomatology is principally acute or chronic hydrocephalus obstructing the foramen of Monro, and the origin of this cyst is controversial, neuroepithelial or endodermal. We report a case of colloid cyst of the third ventricle, associated with cavum veli interpositi. The patient, a 46-years-old female, had suffered from headache, ataxic gait and tremor lasting 6 months. CT scan and homogenous high signal intensity by SR (2450/450) MR image, detected a small round mass in the anterior part of the third ventricle that was of homogenous high density, but without the effect of enhancement. The lateral ventricle was markedly dilated, and a large cavum veli interpositi was found between the third ventricle and the corpus callosum. The cyst was totally removed by transventricular approach, and the result was satisfactory. We reviewed literatures and discussed MRI findings of colloid cysts of the third ventricle. Because of the presence of microvilli covered with coating materials seen in electron microscopic study, we suggested that the colloid cyst was endodermal in origin.

Brain Diseases↗
PubMed1988

Developmental and radiological anatomy of the superficial cerebral convexity vessels in the human fetus.

The superficial cerebral vessels on the convex side of the cerebral hemisphere were investigated using 40 brains of aborted human fetuses (ranging from 2 to 7 months of gestational age), injected with radiopaque material either through the arterial or venous system. These brains, particularly their vessels, were studied in detail through stepwise roentgenography in stereo-pairs, photography and careful dissections. Morphological changes of the superficial vessels of the cerebral convexity reflect the developmental alterations of the cerebral structures, particularly those of the opercula and cerebral sulci. Between the gestational ages of 3 and 4 months, the middle cerebral artery and its tributaries run radially on the sylvian fossa and over the convexity. Anastomoses among the peripheral branches of the anterior, middle and posterior cerebral arteries take place on the convex side of the hemisphere. At the ages of 3 and 4 months, the middle cerebral vein and its tributaries are well developed compared with the superior and inferior cerebral (or ascending and descending cortical) veins. The middle cerebral vein and its tributaries rapidly regress from the 5th to 7th month. The superior and inferior cerebral veins, on the other hand, develop rapidly during this period. Owing to the development of the opercula and resultant depression of the insula, after seven months of gestation the middle cerebral artery and its branches, begin to differentiate into the vallecular (related to the sylvian vallecula or fronto-temporal notch), insular (related to the insular cortex), opercular (related to the frontal, parietal and temporal opercula) and convexity segments (related to the convex side of the hemisphere). The anastomotic veins of Trolard and Labbé are also recognizable at this stage. The superficial sylvian vein in the process of formation may also be detected. The configuration of the cerebral vessels on the convex side of the hemisphere is also affected greatly by the development of the cerebral sulci. These cerebral vessels may run along, or dip into the sulci. Since the development of the superficial cerebral vessels is closely related to that of the cerebral mantle, these studies should be correlated to detail with those of developmental alterations of the intraparenchymal vessels (medullary arteries and veins). The latter investigation will be presented in a future communication.

Cerebral Arteries↗
PubMed1986

Hemangiomas of the central nervous system in Japan: an epidemiological and clinicopathological study with special reference to venous and cavernous malformations.

Our experiences with cerebrovascular malformations in Japanese patients have been reviewed, presenting 29 cases of venous malformation, 30 cases of cavernous angiomas and one case of capillary telangiectasis. We also present the data from the 763 cases of AVM obtained in the cooperative studies which were supported by the Ministry of Health and Welfare of Japan, and discussed the epidemiological and clinicopathological aspects in relation to those reported in the literature. The cooperative studies on these subjects were primarily done in conjunction with the investigation of Moya-Moya disease which is by far frequently found in Japan. Regarding the vascular malformations of the C.N.S., there seem to be no noticeable differences in the epidemiological aspects as seen in Japan and in other countries. It should be stressed also from our experiences that all kinds of vascular malformation, either intracranial or intraspinal, bleed probably more often than we expect. Neurosurgeons should pay more careful attention to these vascular malformations with appropriate concepts of the disease.

Adolescent↗
PubMed1986

Radiologic diagnosis of lateral parasellar masses and their classifications.

Computed tomography (CT) and cerebral angiography of lateral parasellar masses were reviewed and classified into 6 categories according mainly to operative findings, as: 1) intradural or dural masses, 2) pituitary fossa masses, 3) intracranial extradural masses, 4) bony or cartilaginous masses, 5) masses of sphenoid sinus origin, and 6) carcinomas. Each of the 6 categories shows characteristic combinations of 3 cardinal radiologic features. These are: a) transverse displacement of the ganglial and cavernous carotid arteries on antero-posterior carotid angiography, b) erosion or destruction of bone in the lateral parasellar region, and c) sphenoid sinus involvement on CT and conventional radiography. Use of this classification scheme based on the 3 cardinal radiologic features described should be of considerable aid in the diagnosis of lateral parasellar masses.

Brain Neoplasms↗