Biomedical subjects

Jun-Ichi Koyama

Publications and source records attributed to Jun-Ichi Koyama.

4 recordsLinked to original sources

PubMed2006

Subtle computed tomography abnormalities in cerebral deep sinus thrombosis.

A patient with cerebral deep sinus thrombosis, which was not diagnosed on the first examination, is reported. A 46-year-old woman presented with headache and vomiting. Neurological examination and a brain computed tomography (CT) scan showed no obvious abnormal findings. The patient suffered disturbed consciousness on the day after the examination, and was admitted to our emergency centre. A CT scan and magnetic resonance imaging revealed an ischaemic lesion in the left basal ganglia, suggesting deep sinus occlusion. Anticoagulant therapy was administered. One day after admission, a CT scan showed a haematoma and severe brain swelling in the same region. Cerebral angiography demonstrated a straight sinus occlusion. Intracranial pressure was not controlled with hypothermia, and the patient died 25 days after admission. Review of the initial CT scan revealed subtle, early findings of deep venous thrombosis that were missed on first examination.

Anticoagulants↗

PubMed2006

Middle cerebral artery occlusion associated with acute myocardial infarction in the perioperative period--case report.

A 68-year-old woman with no history of cardiac events suffered acute myocardial infarction after surgery for middle cerebral artery (MCA) occlusion manifesting as transient left motor weakness. Diffusion-weighted magnetic resonance imaging revealed multiple infarctions in the right cerebral hemisphere. Magnetic resonance angiography and cerebral angiography demonstrated an occlusion at the horizontal segment of the right MCA and no collateral circulation. Cerebral blood flow study 6 weeks after the initial presentation indicated decreased blood flow in the right cerebral hemisphere. Superficial temporal artery-MCA anastomosis was conducted to prevent recurrent cerebral infarction. Two hours after surgery, her systolic blood pressure fell to 60 mmHg and her consciousness worsened. Emergency coronary angiography indicated occlusion of the right coronary artery. Percutaneous coronary intervention was successfully performed and the subsequent course was uneventful. Preoperative evaluation of the coronary artery may be necessary before surgery for cerebral ischemic disease in both the intracranial and extracranial arteries.

Aged↗

PubMed2005

A saccular-like dissecting aneurysm of the anterior cerebral artery that developed 2 years after an ischemic event.

BACKGROUND: A rare case of a growing dissecting aneurysm, which was located at the horizontal (A1) segment of the anterior cerebral artery (ACA), is reported. CASE DESCRIPTION: A 53-year-old woman experienced left hemiparesis and alien hand syndrome. A computerized tomography scan showed an infarction in the right frontal lobe, and cerebral angiography revealed a false lumen and intimal flap at the A1 segment of the ACA. Magnetic resonance angiography demonstrated that the stenosis progressed 6 months later and improved 1 year later. Cerebral angiography showed a saccular-like aneurysm 2 years later. The surgery was planned for prevention of aneurysmal rupture. The aneurysm, which was cocoon shaped, was exposed surgically and was resected. Histological examination of the aneurysm showed arterial dissection. The postoperative course was uneventful without additional neurological deficits. CONCLUSION: This is the first case report of A1 dissecting aneurysm presenting with an ischemic event in the literature. The sequential change of the configuration was curious to develop aneurysmal dilatation in 2 years. Long-term follow-up is necessary even after disappearance of the arterial dissection.

Aortic Dissection↗

PubMed2002

NeuRobot: telecontrolled micromanipulator system for minimally invasive microneurosurgery-preliminary results.

OBJECTIVE: Microneurosurgery can be performed less invasively with the recent advances in neuronavigation and neuroendoscopy. For even less invasive microneurosurgery, we have developed a telecontrolled micromanipulator system. METHODS: The NeuRobot telecontrolled micromanipulator system was developed. With the use of this system, surgical simulations were performed with a human cadaveric head. RESULTS: The system consists of four main parts, i.e., a micromanipulator (slave manipulator), a manipulator-supporting device, an operation-input device (master manipulator), and a three-dimensional display monitor. Three 1-mm forceps and a three-dimensional endoscope, which could be remotely controlled with three degrees of freedom (rotation, neck swinging, and forward/backward motion), were installed in the slave manipulator. All surgical procedures were accurately performed with this system. CONCLUSION: The use of telecontrolled manipulator systems in neurosurgery is very promising, and we are convinced that this system will facilitate more accurate, less invasive microneurosurgery. The details of the NeuRobot system and preliminary results are presented.

Cadaver↗