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Biomedical subjects

M Tsuura

Publications and source records attributed to M Tsuura.

At least 19 recordsLinked to original sources

Endovascular treatment of unruptured cerebral aneurysms.

76 consecutive patients with 78 unruptured cerebral aneurysms underwent endovascular therapy from July 1999 to May 2004 in our institute. For the wide-necked aneurysms, the remodeling technique, double microcatheter technique, or stent-assisted coil embolization was used, while a parent artery occlusion or covered stent was applied for the giant or fusiform aneurysms. Immediate angiographical results demonstrated 33 complete occlusions, 26 neck remnants, and 14 dome fillings. Four cases were treated with parent occlusion or stenting only, and one case was not treated with embolization but with clipping due to the rupture of the aneurysm during coil embolization. Immediate angiographic findings demonstrated that in aneurysms between 5 to 10 mm, the rate of complete occlusion was 48%, that of neck remnants 33%, and that of dome fillings 27%. In aneurysms between 11 to 25 mm, the rate of complete occlusion was 14%, that of neck remnants 28%, and that of dome fillings was 58%. In the angiographic follow-up results, all aneurysms smaller than 5 mm showed complete occlusion. In aneurysms between 5 to 10 mm, 74% of the aneurysms showed complete occlusion, and 21% showed neck remnants, and 5% showed dome filling. In aneurysms between 10 to 24 mm, 25% showed complete occlusion, while 75% showed dome filling. The overall mortality rate was 0% and the morbidity rate was 3.7% (2 major strokes, 1 minor stroke) at 30-days after embolization. In the clinical follow-up study, one case of a large basilar tip aneurysm caused a fatal rupture 28 months after the initial embolization. Endovascular therapy was performed on the unruptured aneurysms and was found to be an acceptable treatment, except for durability in cases of large aneurysms.

Adult↗

Indirect carotid cavernous fistula appeared after balloon embolization of direct CCF.

The authors describe a case of indirect carotid cavernous fistula (CCF) appearing five months after embolization for traumatic direct CCF, which was treated six months after the trauma. Long-term (six months) venous hypertension to the affected cavernous sinus due to direct CCF and cavernous sinus thrombosis following a balloon embolization were considered as an etiology of the de novo dural arteriovenous fistula. The recurrent symptoms of CCF are usually related to detached balloon disorder, but delayed recurrence may be caused by the de novo dural AVF, if the direct CCF was treated in the chronic state.

Arteriovenous Fistula↗

Combined surgery and endovascular stenting for basilar artery stenosis refractory to balloon angioplasty: technical case report.

The authors report a case of symptomatic basilar artery stenosis treated by stenting via the surgically exposed C1 vertebral artery. This case was initially treated by percutaneous transluminal angioplasty via a transfemoral route but resulted in unsatisfactory dilatation. Stenting via a transfemoral route also resulted in failure because of the coiling of the proximal vertebral artery. Direct puncture of the vertebral artery beyond the coiling portion was tried but a stent could not be delivered beyond the C2 vertebrae. Finally, the vertebral artery was surgically exposed between C1 and the occipital bone and a stent was introduced into the lesion from this portion under fluoroscopic control. The basilar artery was fully opened by stenting without new neurological deficits. Stenting of the basilar artery via a transfemoral route is not always possible even with newer generation stents if the vertebral artery has elongated tortuous curves. Combined surgery and endovascular stenting is one of the alternatives in such cases including our case.

Aged↗

Treatment of restenosis after percutaneous transluminal angioplasty for internal carotid artery stenosis.

The efficacy of repeated percutaneous transluminal angioplasty (PTA) and carotid endarterectomy (CEA) was examined in patients with restenosis after PTA for carotid stenosis. After percutaneous transluminal angioplasty (PTA) for 63 cases of internal carotid stenoses 13 cases of restenosis appeared. They were treated by PTA or carotid endarterectomy. The treatment was chosen by the patient after explanation of each treatment. We initially treated seven patients by repeat PTA and six by carotid endarterectomy. The degree of stenosis improved from 82% to 30% on average after repeated PTA. However, one patient in the PTA group had restenosis, and carotid endarterectomy was then performed. The other cases also had restenosis and were treated by PTA. The six cases treated by carotid endarterectomy were successfully treated without difficulty. The success rate of PTA was 5/7 (71%) in the restenosis cases. Patients with a greater residual stenosis after initial PTA had significantly more frequent restenosis. Repeat PTA and CEA both appeared effective treatment for restenosis after initial PTA, although PTA had a restenosis rate similar to that of initial PTA.

Aged↗

Haemorrhagic complication following percutaneous transluminal angioplasty for carotid stenosis.

We report 2 cases with haemorrhagic complications following percutaneous transluminal angioplasty (PTA) for carotid stenosis. Computed tomography (CT) scanning of these cases demonstrated diffuse subarachnoid haemorrhage in 1 case, and intracerebral haemorrhage in the other case on the next day after PTA. In the latter case, we measured cerebral blood flow velocity and mean transit time with transcranial doppler (TCD) and dynamic CT scan, which demonstrated remarkable increases in the blood flow velocity and peak height, respectively. From these results, postoperative hyperperfusion was suggested to have caused haemorrhagic complications.

Aged↗

Presumed intraventricular meningioma treated by embolisation and the gamma knife.

A 58-year-old woman with a presumed incidentally discovered meningioma in the left lateral ventricle was treated by superselective embolisation and gamma knife therapy. The diameter of the tumour was 40 mm, and its main feeding artery was the left lateral posterior choroidal artery. This vessel was embolised with microcoils. At 8 months following embolisation, the diameter of the tumour had decreased and was stable. The gamma knife was chosen as an adjuvant therapy for the further control 13 months after embolisation. Embolisation and gamma knife therapy may be an alternative treatment for meningiomas where surgical resection appears difficult.

Cerebral Ventricle Neoplasms↗

Endovascular stent placement for cervical internal carotid artery aneurysm causing cerebral embolism: usefulness of neuroradiological evaluation.

We present a case of a cervical internal carotid artery aneurysm that caused cerebral embolism. This lesion was supposed to be a dissecting aneurysm due to blunt neck injury. The large aneurysm with intramural thrombus was treated with endovascular placement of a balloon-expandable stent. Both CT and MRI were useful for evaluating the size and characteristics of the aneurysmal wall. Intravascular ultrasound imaging was also useful for evaluation of the satisfactory stent deployment and identification of the neck of the aneurysm. We discuss effectiveness of endovascular stenting for cervical internal carotid artery aneurysm with intramural thrombus and the usefulness of a combination of the neuroradiological imaging before, during and after the interventional procedure.

Adult↗

Magnetic resonance signal intensity and volume changes after endovascular treatment of intracranial aneurysms causing mass effect.

To determine when and how intracranial aneurysms causing mass effect change following endovascular treatment, we used MRI to assess patients for 2-3 years after the interventional procedure. Nine patients who had aneurysms compressing the surrounding structures underwent endovascular treatment. Proximal occlusion of the parent artery was performed in seven cases, and in two the aneurysm was embolised with microcoils. After embolisation, signal intensity within aneurysms tended to be high on both T1- and T2-weighted images. When there was rapid reduction in size high-signal zones within aneurysms became isointense or gave low signal on T1-weighted images. On T2-weighted images, isointense or low-signal foci appeared within high-signal areas in the aneurysm, giving mixed intensity. In typical cases, the mean volume of the aneurysm fell to approximately 30% of its initial value 2-12 months after treatment. After this, no additional reduction was observed. The aneurysms which showed little signal intensity change tended to shrink more slowly and to a lesser degree than the more typical cases. Aneurysms which gave high signal on both T1- and T2-weighted images early following embolisation shrank more quickly than those showing little signal change.

Adult↗

Carotid endarterectomy and simultaneous percutaneous transluminal angioplasty for tandem internal carotid stenoses.

We treated three patients with tandem internal carotid stenoses in single procedures including carotid endarterectomy (CEA) for the proximal stenosis and percutaneous transluminal angioplasty (PTA) for the distal stenosis. We devised a Y-shaped shunt tube for the CEA, through which a balloon catheter was introduced to perform PTA guided by mobile digital subtraction angiography. No cerebrovascular events occurred during follow-up. Our approach avoids the risk of a second procedure while effectively treating tandem stenoses.

Aged↗

Percutaneous transluminal angioplasty for intracranial arteriosclerotic lesions.

We report 17 cases of intracranial arterial stenosis treated by percutaneous transluminal angioplasty (PTA), including 9 on the intracranial internal carotid (ICA), 4 on the middle cerebral (MCA), and 4 on vertebrobasilar artery (VBA) system. All patients had ischaemic brain symptoms and stenoses of more than 60% (calculated angiographically). We treated four patients by PTA for residual stenoses after thrombolysis for acute occlusion. We used PTA balloon catheters 2.0-3.5 mm in diameter for all procedures. As a rule, the balloon was inflated for 1 min at 6 atm. All arteries were successfully dilated (stenosis less than 50%) except for one treated by PTA for residual MCA stenosis after thrombolysis. The patient died of a massive infarct due to MCA reocclusion caused by arterial dissection. Stenosis recurred in 4 of 16 patients. Repeat PTA was successfully carried out in these cases. However, stenosis recurred in one of these patients 3 months after PTA, but the patient is being followed because he is asymptomatic. PTA of intracranial arteries is effective, but its indications should be based strictly on potential risks, such as acute occlusion derived from arterial dissection.

Aged↗

The effect of endovascular therapy for cerebral arterial spasm, its limitation and pitfalls.

PURPOSE: The effect of endovascular treatment for vasospasm was investigated by analysing the results of patients treated in Wakayama City in 1994. MATERIALS AND METHODS: Ninety nine patients with ruptured cerebral aneurysms, who survived more than one week and were treated in Wakayama City in 1994, were studied. Twenty five patients caused symptomatic vasospasm and 25 were treated by endovascular therapy, percutaneous transluminal angioplasty (PTA) and/or intra-arterial papaverine infusion (IAP). PTA was performed for proximal vasospasm which located in the main arterial trunk, such as ICA, M1, BA (n = 3). IAP was chosen for distal vasospasm which located mainly in the M2, A1, A2 (n = 12). PTA and/or IAP was performed for diffuse vasospasm which located in proximal and distal arteries (n = 10). RESULTS: In the proximal vasospasm group, all patients were good to moderately disabled on the Glasgow outcome scale (GOS). In the distal vasospasm group, 8 patients were good to moderately disabled, and 4 patients were severely disabled. The overall results were as follows: 17 (68%), good to moderately disabled, 4 (16%), severely disabled, 4 (16%), dead. The morbidity and mortality rate was 8/25 (32%) in symptomatic spasm group. CONCLUSION: PTA was very effective especially for proximal vasospasm, but IAP was not always effective for distal or diffuse vasospasm. Diffuse vasospasm revealed a high mortality rate in spite of the endovascular therapy.

Adult↗

The role of angiogenic factor bFGF in the development of dural AVFs.

PURPOSE: Dural arteriovenous fistulas (dAVFs) are known to be acquired disorders. Angiogenic stimulants, such as basic fibroblast growth factor (bFGF), may be involved in the evolution of this disorder. We examined the appearance and localization of bFGF, in human dAVF sinuses, versus a control using immunohistochemical techniques, to evaluate these qualitative differences. PATIENTS AND METHODS: Four human dural sinuses from dAVF patients, and one control dural sinus were removed at surgery or autopsy and used for this study. Immunohistochemistry for bFGF was performed in all five specimens to identify its appearance and localization. Immunohistochemistry for alpha smooth muscle actin, factor VII related antigen, and macrophage (CD-68) were done in all tissues to identify the bFGF positive cell types. RESULTS: In the control dural sinus, there was negative staining by bFGF immunohistochemistry. However, in all four sinuses of the dAVF patients, smooth muscle cells, endothelial cells, and meningeal cells were stained positively in various degrees by bFGF immunohistochemistry. CONCLUSION: bFGF may be significant in the development of dAVFs, judging from its strong immunoreactivity in the sinuses of dAVF patients.

Adult↗

Preoperative embolization of meningiomas fed by ophthalmic branch arteries.

BACKGROUND: The efficacy of preoperative embolization for hypervascular meningiomas mainly fed by the branches of the ophthalmic arteries was examined. CASES AND METHODS: Five hypervascular meningiomas mainly fed by the branches of the ophthalmic arteries, four posterior ethmoidal arteries, one anterior falx artery, and one recurrent middle meningeal artery were embolized with Gel-foam powder, polyvinyl alcohol (PVA) particles, and/or microcoils as a preoperative treatment using a microcatheter. RESULTS: Catheterization of the ophthalmic and tumor feeding artery was possible and feeding arteries and lesion embolization were effective to reduce the bleeding during surgery in all cases. In three cases, visual acuity and visual field were preserved. However, in one case, visual acuity and visual field defect appeared due to the migration of Gelfoam powder (Upjohn, Kalamazoo, MI) into the retinal artery. In another case, the retinal artery was embolized with the feeding arteries since the patient was already blind. CONCLUSION: Embolization of hypervascular meningioma feeding vessels arising from the ophthalmic artery is possible and effective with preservation of vision, if embolic agents are injected gently enough not to reflux into the central retinal artery.

Adult↗

[Diffusion/perfusion MRI study on cerebral ischemia in a rat embolism model].

To determine whether intracerebral distribution of clot emboli can induce perfusion deficits and ischemic brain injury in a rat embolism model, diffusion/perfusion magnetic resonance imaging techniques were employed using a 4.7 Tesla imager. Clot emboli produced from venous blood were injected into the right internal carotid artery of male Sprague-Dawley rats. Diffusion-weighted spin-echo imaging was used to detect early ischemic injuries due to cytotoxic edema every 30 minutes. Sequential echo-planar imaging (EPI), as a form of perfusion imaging, was carried out following bolus i.v. injection of the magnetic susceptibility contrast agent Dy DTPA-BMA. Images (EPI) were also made during clot embolization to localize the distribution of the emboli. The images obtained showed signal loss in the right hemisphere corresponding to the distribution of the emboli result of the magnetic susceptibility effect of deoxyhemoglobin. The spatial distribution of the signal loss corresponded to the perfusion deficits, decreased ADC (apparent diffusion coefficient) areas on diffusion images, and histological abnormalities on TTC-stained specimens. After intra-arterial streptokinase infusion following clot embolization, decreased perfusion deficits and abnormal ADC areas were monitored by diffusion/perfusion MRI. Diffusion/perfusion MR imaging thus provided excellent in vivo mapping of the distribution of the emboli in relation to cerebral perfusion deficits and acute ischemic injury in the rat embolism model.

Animals↗

Clinical use of mechanical detachable coils for dural arteriovenous fistula.

Seven dural arteriovenous fistulas were successfully embolized with mechanical detachable coils. Two lesions were located in the transverse-sigmoid sinus, four in the cavernous sinus, and one in the marginal sinus. All lesions were completely occluded on postembolization angiography. No recurrent symptoms appeared during a mean follow-up period of 11 months. Owing to the length and retrievability of the mechanical detachable coils, embolization was quicker and safer, and coils were packed more densely, than is possible with conventional coils. Coil migration was avoided because coils of the appropriate size were chosen before they were placed.

Aged↗

NG-nitro-L-arginine delays the development of brain injury during focal ischemia in rats.

BACKGROUND AND PURPOSE: The present study was designed to determine the effect of nitro-L-arginine, the inhibitor of nitric oxide synthesis, on the evolution of cytotoxic brain edema during focal cerebral ischemia. METHOD: Diffusion-weighted and contrast-enhanced, perfusion-sensitive magnetic resonance imaging was performed in anesthetized, mechanically ventilated rats at 30 minutes and 1, 2, and 3 hours after occlusion of the middle cerebral artery combined with coagulation of the basilar artery. At the onset of ischemia, the animals were infused intravenously with 0.5 mL of either 0.9% NaCl or nitro-L-arginine (30 mg/kg). The severity of cytotoxic edema was evaluated based on changes in the water apparent diffusion coefficient (ADC) derived from diffusion-weighted images. The size of the area affected by ischemia was evaluated 3 hours after occlusion using 2,3,5-triphenyltetrazolium chloride (TTC) staining. RESULTS: The percentage decrease of ADC in the striatum of rats pretreated with nitro-L-arginine was significantly smaller (P < .05) than in the control group at 30 minutes and 1 and 2 hours of ischemia. The ADC in the injured cortex of nitro-L-arginine-treated rats did not differ significantly from the ADC value measured in the contralateral cortex until 3 hours after the occlusion. However, at 3 hours of ischemia the percentage decrease of ADC in both the striatum and the cortex of either group of rats was similar. This transient attenuation of ADC drop during ischemia after nitro-L-arginine pretreatment occurred concurrently with a transient improvement of blood supply to the ischemic regions. The percentage of hemispheric area with abnormal TTC staining after 3 hours of ischemia did not differ between control and nitro-L-arginine-treated rats. CONCLUSIONS: Nitro-L-arginine delays the development of ischemic injury by retarding cytotoxic brain edema. This effect is, at least partially, mediated by an improvement in blood supply to the ischemia tissues.

Animals↗

Stenotic kinking of the cavernous internal carotid artery with a giant intra-cavernous aneurysm: case report.

We report a giant aneurysm of the cavernous internal carotid artery with proximal internal carotid stenosis. The stenosis showed two typical features: a kink at the stenosis and location at the exit from the carotid canal. We believe that the cavernous portion of the internal carotid artery is compressed medially by the giant aneurysm and a kink occurs at the point where the artery leaves the bony carotid canal.

Aneurysm↗