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Kiyoyuki Yanaka

Publications and source records attributed to Kiyoyuki Yanaka.

At least 37 records · Page 2Linked to original sources
PubMed2003

Feasibility of internally referenced brain temperature imaging with a metabolite signal.

The feasibility of using a metabolite signal as an internal reference for self-referenced temperature distribution measurement was examined. Line scan echo-planar spectroscopic imaging (LSEPSI) was applied to obtain quick multi-voxel spectroscopic measurements and to avoid possible spectral degradation from motion. Temperature distribution in a rabbit brain in vivo was successfully visualized by means of the chemical shift of water, which was measured by using naturally abundant (up to 10 mM) N-acetyl-aspartate (NAA) as the reference signal. Unlike the phase-mapping approach, this technique does not require a pixel-by-pixel subtraction. Therefore, in theory, it is more resistant to inter-scan motion or changes in susceptibility. The spatial and temporal resolutions of this technique are 1.5 cm3 and 4.5 min. A higher signal-to-noise ratio and optimization of the water and outer-volume suppression capabilities will be required to further enhance the temperature-mapping capabilities.

Animals↗
PubMed2003

Persistent primitive otic artery with IC-cavernous aneurysm.

We describe a case of unruptured internal carotid artery aneurysm associated with persistent primitive otic artery variant in a 48 year old woman. The aneurysm was successfully treated by endovascular embolisation. A possible pathogenesis of this rare condition is discussed.

Arterio-Arterial Fistula↗
PubMed2003

Cervical spondylotic myelopathy: surgical results and factors affecting outcome with special reference to age differences.

OBJECTIVE: A variety of factors may affect the surgical outcome in patients with cervical spondylotic myelopathy. The aim of this study is to analyze the prognostic factors by comparing younger and elderly patient groups on the basis of preoperative radiological and clinical data. METHODS: To assess the prognostic factors after surgery had been performed, the clinical and radiological data of 64 patients who underwent expansive laminoplasty were reviewed. Patients were classified into two groups, a younger patient group (<65 yr of age; n = 29) and an elderly patient group (>/=65 yr of age; n = 35). The neurological status of the patients was assessed by use of the Japanese Orthopaedic Association scale. Radiological features were examined with computed tomographic myelography and magnetic resonance imaging. The effects of the clinical and radiological findings on neurological outcome were investigated. RESULTS: The preoperative and postoperative mean Japanese Orthopaedic Association scores in elderly patients were significantly lower than those in younger patients. For elderly patients, the transverse area of the spinal cord at the level of maximum compression and symptom duration were the factors that predicted an excellent recovery. In contrast, the transverse area was the only predictor of excellent recovery in younger patients. Age, preoperative Japanese Orthopaedic Association score, canal diameter, and an intensity change on the spinal cord were not predictive in either age range. CONCLUSION: The transverse area of the spinal cord may be a reliable predictor of excellent recovery in both younger and elderly patient groups. Shorter symptom duration was an important factor in the excellent recovery of elderly patients.

Activities of Daily Living↗
PubMed2003

Ruptured middle cerebral artery aneurysm with intramural myxoid degeneration in a child.

A 9-year-old girl presented with a subarachnoid hemorrhage. Cerebral angiography showed a saccular aneurysm arising from the horizontal portion of the right middle cerebral artery. The aneurysm was successfully clipped, and the dome of the aneurysm was excised for pathological study. Histological examination of the aneurysm wall showed that the entire thickness of the wall showed an increased myxoid degeneration. No dissection was present. Most intracranial aneurysms in childhood are believed to be of the saccular type similar to that in adults, but the pathogenesis of the aneurysm formation remains controversial. Myxoid degeneration may cause intracranial saccular aneurysm with eventual rupture, even in the absence of dissection. This is the first case reported of a ruptured saccular aneurysm caused by myxoid degeneration in a child. The possible pathophysiology is discussed.

Aneurysm, Ruptured↗
PubMed2003

Small unruptured cerebral aneurysms presenting with oculomotor nerve palsy.

OBJECTIVE: Symptomatic unruptured aneurysms have been considered at relatively high risk for future rupture, and the majority of aneurysms that cause symptoms of mass effect are large. Unruptured aneurysms smaller than 1 cm in diameter sometimes cause neurological symptoms, but their clinical aspects remain obscure. In this article, we review our experience with small unruptured aneurysms presenting with oculomotor nerve palsy. METHODS: Sixteen patients with unruptured aneurysms smaller than 1 cm presenting with oculomotor nerve palsy were included in this study. The patients' clinical profiles were reviewed, and factors affecting the recovery of oculomotor function were determined. RESULTS: The mean size of the aneurysms was 5.8 +/- 1.4 mm. Eleven patients (68.8%) had preceding retrobulbar pain. Fifteen patients underwent successful microsurgical clipping or intravascular embolization, but one patient died of aneurysm rupture before surgery. Seven patients (43.8%) had a complete recovery of oculomotor function, six (37.5%) had an incomplete recovery, and two (12.5%) remained unchanged after treatment. The mean interval between the onset of oculomotor nerve palsy and treatment was 4.7 +/- 3.3 days in patients with complete recovery, 24.2 +/- 15.5 days in patients with incomplete recovery, and 41.0 +/- 12.7 days in unchanged patients. Early surgery resulted in more complete recovery of neural function (P < 0.01). CONCLUSION: Unruptured aneurysms smaller than 1 cm can cause neurological symptoms of mass effect. We recommend timely surgery, preferably within 5 days, to avoid not only aneurysm rupture but also functional disability even in patients with unruptured aneurysms smaller than 1 cm.

Adult↗
PubMed2003

Multiple intracranial arterial stenoses around the circle of Willis in association with Graves' disease: report of two cases.

OBJECTIVE AND IMPORTANCE: The association of Graves' disease with multiple intracranial arterial stenoses is rare. CLINICAL PRESENTATION: We report on two Japanese women who experienced the concurrence of Graves' disease and cerebral ischemia attributable to multiple intracranial arterial stenoses around the circle of Willis. Clinically, these patients demonstrated hyperthyroidism, goiter, ophthalmopathy, and ensuing ischemic strokes. Cerebral angiography demonstrated multiple intracranial arterial stenoses around the circle of Willis in both cases. These cases did not meet the full diagnostic criteria for moyamoya disease, in that there were no abnormal, net-like, collateral vessels, but the other clinical and angiographic findings were consistent with this condition. INTERVENTION: After normalization of their hormonal conditions, the patients underwent cerebral revascularization procedures. Both patients achieved excellent recoveries and returned to normal daily life after treatment. CONCLUSION: Multiple intracranial arterial stenoses and Graves' disease may occur simultaneously. Such cases may offer new insights into the pathogenesis of these two conditions. It is important to study more patients with this dual condition, to obtain more evidence of the relationship between genetic and immunogenic backgrounds.

Adult↗
PubMed2003

Aneurysm and fenestration of the azygos anterior cerebral artery--case report.

A 78-year-old female suffered sudden onset of nausea and headache. Computed tomography demonstrated diffuse subarachnoid hemorrhage. Cerebral angiography demonstrated an aneurysm arising from the right A1 segment of the azygos anterior cerebral artery, and the hypoplastic left A1. A right frontotemporal craniotomy was performed to obliterate the aneurysm by neck clipping. Surgical exploration found the fenestration of the right A1 and showed that the aneurysm had originated from the bifurcation of the fenestrated A1 and a small perforating artery arising from the fenestration. This unusual combination of an aneurysm associated with a fenestration of the right A1 and contralateral A1 hypoplasia may have been caused by local hemodynamic stress.

Aged↗
PubMed2003

Head and neck extension-fixation with a head frame for exposure of the distal internal carotid artery in carotid endarterectomy--technical note.

Adequate exposure of the distal internal carotid artery (ICA) for carotid endarterectomy may be difficult to achieve because of the position of the mandible and associated soft tissues. A simple yet effective use of a head frame is described to gain several centimeters of exposure of the distal ICA. The patient's head and neck are fixed in an extension position using a radiolucent head frame. Nasotracheal intubation and secure taping of the chin are also employed to keep the mouth closed and to prevent the mandible from spontaneously hanging down. The head frame tightly fixes the patient's neck, so the mandible does not disturb the surgical field throughout the operation. This simple method maximizes exposure of the distal ICA. The radiolucent head frame also enables intraoperative angiography to confirm the patency of the ICA and the absence of flap formation. This simple technique is useful for exposing the distal ICA.

Carotid Stenosis↗
PubMed2003

Intraoperative angiographic assessment of graft patency during extracranial-intracranial bypass procedures.

The use of intraoperative angiography to monitor graft patency was retrospectively reviewed in extracranial-intracranial bypass procedures. Forty-two patients underwent 43 extracranial-intracranial bypass procedures with the use of intraoperative angiography. Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass was performed in 41 patients (42 procedures) with ischemic cerebrovascular diseases, and vertebral artery-MCA bypass using radial artery graft for intentional ligation of the common carotid artery in one patient with nasopharyngeal carcinoma. Intraoperative angiography provided high-quality subtraction images in every case. There were no complications due to angiography. Graft occlusion was observed intraoperatively in three cases, but an additional procedure reopened the occluded graft in all three cases. Graft patency rate was 100% after surgery. Outcome was excellent in 40 patients and good in one patient who underwent STA-MCA bypass. Intraoperative angiography provides useful information regarding graft patency during bypass surgery. Intraoperative assessment prior to wound closure allows for the recognition and correction of technical failure and decreases the risk of postoperative complications.

Adult↗
PubMed2003

Combined laminoplasty with posterior lateral mass plate for unstable spondylotic cervical canal stenosis--technical note.

A technique of combined expanding laminoplasty using longitudinal interspinous iliac bone graft with posterior lateral mass plate is described for the treatment of cervical canal stenosis associated with spinal instability. A 52-year-old male and a 76-year-old female presented with cervical myelopathy. Imaging studies demonstrated spondylotic cervical canal stenosis associated with spinal instability. Posterior stabilization with lateral mass plate by the Axis Fixation System was performed after expanding laminoplasty using interspinous iliac bone graft. The symptoms improved and instability and malalignment (in the female patient) also improved after surgery. This combined surgical technique allows decompression of the spinal cord, immediate internal fixation by plate fixation, and subsequent long-term stabilization by interspinous bony fusion. This technique is indicated in selected patients with multiple segment spondylotic cervical canal stenosis associated with instability and/or malalignment of the spinal column for which simultaneous decompression and stabilization are required.

Aged↗
PubMed2003

Cervical myelopathy caused by hypoplasia of the atlas and ossification of the transverse ligament--case report.

A 79-year-old Japanese female presented with symptomatic cervical myelopathy caused by a hypoplastic posterior arch of the atlas and ossification of the transverse ligament. Neuroradiological examination demonstrated a hypoplastic posterior arch of the atlas and ossification of the transverse ligament. The cervical spinal cord was compressed at the level of the atlas by both the hypoplastic posterior arch of the atlas and the ossification of the transverse ligament. The patient underwent C-1 laminectomy, which arrested the progressive myelopathy and resulted in a good recovery. Atlas hypoplasia with ossification of the transverse ligament may be associated with Asian ethnicity.

Aged↗
PubMed2003

Significance of a small bulge on the basilar artery in patients with perimesencephalic nonaneurysmal subarachnoid hemorrhage. Report of two cases.

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (SAH) is a distinct type of hemorrhage with a characteristic bleeding pattern and an excellent clinical outcome. The cause of this benign form of SAH remains unknown. The authors report on two cases of perimesencephalic nonaneurysmal SAH in which a small bulge on the basilar artery (BA) was demonstrated on three-dimensional rotational angiography studies. Based on data from these cases, one may infer that the lesion on the BA is responsible for the SAH. The possible pathogenesis is discussed.

Basilar Artery↗
PubMed2002

Fatal cerebral infarction after intraventricular hemorrhage in a pregnant patient with moyamoya disease.

Moyamoya disease is a progressive occlusive cerebrovascular disorder of unknown etiology. We describe a case of a fatal cerebral infarction after intraventricular hemorrhage in a 29-year-old primipara with moyamoya disease. The patient had been stable for about 10 days after the initial hemorrhage, but she showed a fulminant clinical course of cerebral infarction, and died on the 16th day after the initial hemorrhage. Abnormality in coagulation system and/or cerebral vasospasm may have resulted in such a fulminant clinical course. A possible pathogenesis of this rare condition is discussed.

Adult↗
PubMed2002

Coil migration during endovascular treatment in a patient with Galenic arteriovenous malformation.

High flow arteriovenous malformations are commonly treated by using an endovascular approach with detachable coils. Although the risk of coil migration or distal embolisation into the venous system is almost always a consideration when treating these lesions, coil migration of a coil mass comprised of several coils is uncommonly seen, and not recorded. We report a case of Galenic arteriovenous malformation in a 22-year-old male in which coil migration was observed during the endovascular procedure. Possible mechanisms are discussed.

Adult↗
PubMed2002

Repair of a tear at the base of a blister-like aneurysm with suturing and an encircling clip: technical note.

OBJECTIVE: An aneurysm can produce large defects in the parent vessel if the aneurysm tears at the neck of the vessel. The authors present a technique to repair a tear at the base of a blister-like aneurysm encountered during microsurgical clipping of an anterior wall aneurysm of the internal carotid artery. METHODS: The repair technique involved suturing and covering the aneurysm with an encircling aneurysm clip. A large tear had destroyed the vessel's tubular structure, and repair was not sufficient using an encircling clip alone. Two microsuture stitches were placed on the tear, so that a split artery re-formed a tubular structure. The lesion was then covered with Surgicel (Ethicon, Inc., Somerville, NJ) and fibrin glue. When the Surgicel and fibrin glue were applied, the temporary clip on the distal internal carotid artery was removed for a moment, allowing retrograde blood flow to provide the counterforce necessary to maintain the vessel's tubular structure. An encircling clip was then applied to cover the entire circumference of the lesion. RESULTS: This method required only a short occlusion time for arterial repair, thus helping avoid ischemic complications. The patient awoke with transient hemiparesis, but recovery was prompt. CONCLUSION: This technique is useful for repairing an aneurysmal tear at its base, especially if the tear is large.

Aneurysm, Ruptured↗
PubMed2002

Ruptured aneurysm of the ophthalmic artery trunk demonstrated by three-dimensional rotational angiography: case report.

OBJECTIVE AND IMPORTANCE: Aneurysms arising from the ophthalmic artery are extremely rare, compared with carotid-ophthalmic aneurysms arising from the wall of the internal carotid artery. We present a very unusual type of aneurysm arising from the ophthalmic artery itself. CLINICAL PRESENTATION: A 54-year-old man presented with a sudden onset of headache and was transferred to a local hospital. Computed tomography demonstrated subarachnoid hemorrhage around the left anterior clinoid process, but digital subtraction angiography failed to localize the source of the hemorrhage. The patient was referred to our hospital for further evaluation and treatment. Conventional cerebral angiography did not reveal the source of the hemorrhage, but three-dimensional rotational angiography clearly demonstrated an aneurysm arising from the ophthalmic artery trunk, apart from the internal carotid artery. INTERVENTION: The patient underwent microsurgical clipping of the aneurysm via a left pterional craniotomy. The aneurysm originated from the bifurcation of the ophthalmic artery and a perforating artery to the optic nerve. The aneurysm was successfully obliterated, and the postoperative course was uneventful. CONCLUSION: This report is the first to describe a case of a ruptured aneurysm arising from the ophthalmic artery trunk. We discuss the clinical significance of an aneurysm at this site, as well as the role of three-dimensional rotational angiography in determining the source of subarachnoid hemorrhage.

Aneurysm↗