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Tsuyoshi Tada

Publications and source records attributed to Tsuyoshi Tada.

25 records · Page 2Linked to original sources
PubMed2003

Microvascular pathological features of immediate perinidal parenchyma in cerebral arteriovenous malformations: giant bed capillaries.

OBJECT: The behavior of brain tissue in cases of arteriovenous malformations (AVMs) is a matter of debate. The authors believe that the local microvascular environment in the AVM bed shares the hemodynamic changes influencing that behavior in one way or another. The purpose of this study was to investigate the microvascular pathological features in the immediate perinidal brain tissue. METHODS: This retrospective study was conducted using excised AVM specimens obtained in 35 patients, from which the authors selected 20 specimens that fulfilled the criteria for sufficient brain tissue around the excised nidus. Specimens were stained with hematoxylin and eosin, and the immediate perinidal microvascular environment was examined using light microscopy. CONCLUSIONS: Eighty-five percent of the AVMs studied showed the presence of huge, dilated capillaries, and 65% showed severe congestion of these capillaries. The authors have named these capillaries "giant bed capillaries." In this study capillary bleeding was shown in AVMs, and a pericapillary space was seen around some vessels. The brain parenchyma containing AVMs with these findings proved to be significantly ischemic.

Adolescent↗
PubMed2003

Clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma.

OBJECT: The clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma were retrospectively analyzed to improve the perioperative management of the circulation of cerebrospinal fluid. METHODS: A retrospective analysis was performed in 236 patients with unilateral vestibular schwannomas. The patients' ages ranged from 17 to 83 years (mean 53.6 +/- 13.2 years), and the diameters of the tumors the patients harbored ranged from 5 to 60 mm (mean 30.5 +/- 12.7 mm). Hydrocephalus was present before tumor resection in 33 patients (14%) and in six of these patients focal dilation of the sylvian fissures was noted. There was a significant correlation between the incidence of hydrocephalus and tumor size. The incidence of preoperative hydrocephalus among elderly patients (> or = 65 years of age) was 28.6% and that among younger patients (< 65 years of age) was 10.8%. Tumors in elderly patients with hydrocephalus (mean tumor diameter 32.8 +/- 11.7 mm; 12 patients) were significantly smaller than those in younger patients (mean tumor diameter 41.7 +/- 10.9 mm; 21 patients). Among patients with tumors smaller than 30 mm (114 patients), the incidence of hydrocephalus in elderly patients (25%) was 12-fold higher than that in younger patients (2.1%). Six patients with hydrocephalus who had focal dilation of the sylvian fissures were significantly older than 27 patients with hydrocephalus in whom there was no focal dilation. The dilated sylvian fissures collapsed in two patients spontaneously after tumor resection and in the other four patients after shunt placement. CONCLUSIONS: The incidence of associated hydrocephalus is higher in older patients. Communicating hydrocephalus tends to occur in elderly patients. Enlargement of the ventricles with focal dilation of the sylvian fissures should not be misinterpreted as physiological brain atrophy.

Adolescent↗
PubMed2002

A head holder for magnetic resonance imaging that allows the stereotaxic alignment of spontaneously occurring intracranial mouse tumors.

The use of stereotaxic neurosurgery in rodent models of human disease requires the alignment of central nervous system (CNS) structures that can be identified and surgically approached with great accuracy. Current technologies make possible development of mouse lines with enhanced predispositions for the development of various diseases including tumors. When such tumors arise in the brain their location is unpredictable. Obtaining a biopsy or stereotaxically delivering local therapy requires that the site of such tumors be known with great precision. We devised a method to correlate images of mouse brain tumors acquired by magnetic resonance imaging (MRI) with stereotaxic coordinates that can be used for obtaining biopsies or administering local therapy. We constructed a head holder containing a pair of tubes filled with a substance that could be imaged by MR and which were separated by varying distances. This allowed the precise localization of the tumor in all three dimensions. The strategy we employed is adaptable to other imaging modalities and to other body sites.

Animals↗
PubMed2002

Chronic subdural hematoma after transsphenoidal surgery.

Chronic subdural haematoma has not been reported as a complication of transsphenoidal surgery. We present a case of pituitary adenoma which was gross-totally removed by transsphenoidal surgery with the enlarged sellar opening. Postoperative serial imaging showed massive air accumulation in both frontal subdural spaces followed by subdural fluid collection and subsequent chronic subdural haematomas 2 months later. We conclude that close follow up imaging study is required to avoid overlooking chronic subdural haematoma when massive air is introduced into the subdural space by the transsphenoidal surgery.

Adenoma↗
PubMed2002

Disturbed spatial learning of rats after intraventricular administration of transforming growth factor-beta 1.

Patients with subarachnoid hemorrhage (SAH) who later suffer hydrocephalus show persistently high levels of transforming growth factor-beta 1 (TGF-beta 1) in the cerebrospinal fluid after the onset of SAH. Recombinant TGF-beta 1 induces hydrocephalus in mice. This study examined the spatial learning ability of rats after intraventricular administration of TGF-beta 1. Thirteen-week-old Wistar rats were treated with 0.8 or 8.0 micrograms of human recombinant TGF-beta 1 by direct injection or via osmotic pump. Three months later, their spatial learning ability was evaluated with a Morris water maze. Ventricular size, ultrastructural features, and sodium-potassium-adenosine triphosphatase (Na+, K(+)-ATPase) activity of the subarachnoid space were examined. All three TGF-beta 1-treated groups clearly exhibited impaired spatial learning ability, but they did not exhibit ventricular dilation. Histological examination revealed subarachnoid fibrosis and deactivation of Na+, K(+)-ATPase in the arachnoid cells. These findings are similar to those of our previous experiments involving injection of TGF-beta 1 in mice. The present and previous studies suggest that subarachnoid fibrosis is an important factor in the disturbance of the spatial learning ability of rats, whereas ventricular size is less important.

Animals↗
PubMed2002

Radiometric analysis of paraclinoid carotid artery aneurysms.

OBJECT: Classification of paraclinoid carotid artery (CA) aneurysms based on their associated branching arteries has been confusing because superior hypophyseal arteries (SHAs) are too fine to appear opacified on cerebral angiograms. The authors performed a retrospective radiometric analysis of surgically treated paraclinoid aneurysms to elucidate their angiographic and anatomical characteristics. METHODS: A retrospective analysis was made of 85 intradural paraclinoid aneurysms in which the presence or absence of branching arteries had been determined at the time of surgical clipping. The lesions were classified as supraclinoid, clinoid, and infraclinoid aneurysms based on their relation to the anterior clinoid process on lateral angiograms of the CA. The direction of the aneurysms were measured according to angles formed between the medial portion of the horizontal line crossing the aneurysm sac and the center of the aneurysm neck on anteroposterior angiograms. Branching arteries were associated with 68 aneurysms, of which 28 were ophthalmic artery (OphA) lesions (32.9%) and 40 were SHA ones (47.1%); associated branching arteries were absent in 17 aneurysms (20%). Twenty-five aneurysms (29.4%) were located at the supraclinoidal level, 46 (54.1%) at the clinoidal, and 14 (16.5%) at the infraclinoidal. The majority of aneurysms identified at the supraclinoidal level were OphA lesions (44%) or those unassociated with branching arteries (48%), with mean directions of 57 degrees or 67 degrees, respectively. At the clinoidal level, the mean directions of aneurysms were 76 degrees in six lesions unassociated with branching arteries (13%), 43 degrees in 16 OphA lesions (35%), and -11 degrees in 24 SHA ones (52%). All aneurysms at the infraclinoidal level arose at the origin of the SHAs, with a mean direction of -29 degrees, and most of these were embedded in the carotid cave. CONCLUSIONS: Aneurysms arising from the SHA can be distinguished from those not located at an arterial division by cerebral angiography, because SHA lesions are usually located at the medial or inferomedial wall of the internal carotid artery at the clinoidal or infraclinoidal level. Their distribution correlates well with the reported distribution of SHA origins. The carotid cave aneurysm is a kind of SHA lesion that originates at the most proximal intradural CA.

Adult↗