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Biomedical subjects

H Touho

Publications and source records attributed to H Touho.

At least 19 recordsLinked to original sources
PubMed2000

Long-term follow-up study of unruptured vertebral artery dissection: clinical outcomes and serial angiographic findings.

OBJECT: Although the spontaneous occurrence of an unruptured vertebral artery (VA) dissection has increasingly been recognized as a relatively common cause of stroke, and the clinical aspects of this lesion have gradually been determined, its natural course remains obscure. The main goal of this study was to clarify the management protocol for this condition by examining serial angiographic changes in patients with unruptured VA dissections. METHODS: Seventeen patients with unruptured VA dissections, including 13 men and four women, were clinically and angiographically examined between 1993 and 1998. All patients were observed using serial angiography studies. The initial angiography examinations most frequently revealed stenotic lesions (appearance of a pearl-and-string sign or string sign) in eight (47.1%) of 17 cases. In 15 cases (88.2%), changes in the lesions were evident on follow-up angiography studies. Stenotic lesions resulted in occlusion in four cases, normalization in three, and subsequent formation of an aneurysm in one case, which was treated successfully by proximal occlusion of the affected vessel performed using a detachable balloon. Occluded lesions, which were initially observed in three patients, recanalized in two patients and remained unchanged in one patient. Fusiform dilation alone was demonstrated in three patients during the initial angiography session; these lesions became normalized or were unchanged on follow-up studies. Saccular aneurysms were observed in two patients. In one of these cases, proximal ligation of the parent artery was successfully performed because of subsequent aneurysm enlargement. A double lumen, which appeared in one patient with an extradural VA dissection, became occluded. Magnetic resonance T2-weighted imaging studies revealed infarction corresponding to the posterior circulation in seven cases. During long-term observation in this series, good or excellent recovery was obtained in 14 (87.5%) of 16 patients, and moderate or severe disability in two (12.5%); one patient was lost to follow up after the second angiography study. CONCLUSIONS: A follow-up angiography study must be performed during the early stage (within approximately 3 weeks after onset of symptoms) to confirm the formation or enlargement of an aneurysm, because such conditions may be amenable to surgical treatment. Unruptured VA dissection could otherwise be treated and followed conservatively. Although the majority of dissected lesions seem likely to stabilize within a few months, as evidenced on angiography, in some cases a longer observation period is required.

Adult↗
PubMed1999

Falx meningioma presenting as acute subdural hematoma: case report.

BACKGROUND: Acute subdural hematomas caused by meningiomas have been rarely encountered. Pathophysiologic mechanisms and clinical considerations in these patients have not been sufficiently explored. We addressed the possible mechanism of spontaneous hemorrhage in our case and briefly discuss the optimal treatment. CASE DESCRIPTION: This case of falx meningioma presenting as an acute subdural hematoma in a 78-year-old woman is described. On initial computed tomography (CT), an enhancing tumor of the falx appeared to be the cause of hemorrhage. Only faint contrast staining in the periphery of the tumor was seen on right external carotid arteriograms, with no evidence of other vascular supply. Extravasation of contrast material during the procedure occurred suddenly and was successfully treated by endovascular embolization using a microcatheter. The hematoma was emergently evacuated with gross total removal of the tumor. Pathologic examination confirmed a transitional meningioma with abundant hyalinized structures. Disruption of a thin-walled vessel adjacent to the tumor capsule was assumed to be the site of hemorrhage. CONCLUSIONS: The longstanding ischemia of the tumor was considered to have produced the deposition of hyalin in the tissue, which changed the hemodynamics within the tumor, producing vascular stress leading to rupture. The prognosis of patients with meningiomas complicated by acute subdural hematoma is generally poor, with mortality reported in approximately one-half of such patients. Surgical exploration is the most effective treatment and should be conducted before irreversible brain damage has occurred.

Acute Disease↗
PubMed1999

Embolectomy for acute embolic occlusion of the internal carotid artery bifurcation.

BACKGROUND: Acute occlusion of the distal intracranial segment of the internal carotid artery (ICA) causes sudden severe hemispheric ischemia. A low rate of recanalization and a high mortality rate for this condition have been noted, even with endovascular treatment. METHODS: We report the results of emergency embolectomy in six patients with acute embolic occlusion of the internal carotid artery (ICA) bifurcation. All six patients were admitted to our institute within 2 h of the onset of symptoms. Computed tomography (CT) scans on admission revealed no low-density or high-density regions in any patients. The time between onset of symptoms and completion of angiography ranged from 2 to 4 h (2.8 +/- 0.7 h). RESULTS: Emergency embolectomy was performed for each patient. Recanalization was confirmed angiographically in four of the patients. In the remaining two patients, massive infarction in the territory of the ICA was detected on the CT scans obtained the day of the operation, and postoperative angiography was not performed in these two cases. These two patients died of uncal herniation 6 days after onset. Two of the six patients were able to walk with a cane 2 months after surgery. The remaining two patients were unable to walk or attend to their own bodily needs without assistance. The time elapsed between onset of symptoms to reopening of the occluded vessel was within 6 h in the four surviving patients. The recanalization rate was 66.7% (4/6) for the embolectomy procedure, significantly higher than that (12.5%) of the thrombolytic therapy reported in a previous study. CONCLUSIONS: In summary, open embolectomy can be performed when the time after onset of symptoms is less than 6 h.

Acute Disease↗
PubMed1999

End-to-end anastomosis of the posterior inferior cerebellar artery before excision of a meningioma involving the lower clivus and the foramen magnum. Case report.

BACKGROUND: Petroclival and foramen magnum meningiomas sometimes encase the vertebrobasilar arterial system. Magnetic resonance imaging can clearly reveal such encasement. The case presented here was of a meningioma involving the lower clivus and the foramen magnum, encasing a lateral segment of the posterior inferior cerebellar artery (PICA), despite the fact that no definitive diagnosis of the encasement of the PICA was made on preoperative radiological examination. End-to-end anastomosis of the PICA was necessary before excision of the tumor. METHODS: A 55-year-old woman presented with complaints of headache and numbness of the right upper extremity. Gadolinium diethylene-thiamine-pentaacetic acid enhanced T1-weighted magnetic resonance (MR) images showed a homogeneously enhanced mass lesion involving the lower clivus and the foramen magnum. Direct surgery was then performed, and the lateral medullary segment of the left PICA was found to be encased by the tumor. End-to-end anastomosis was performed using No. 10-0 interrupted monofilament nylon sutures. Total removal of the tumor was performed after completion of the anastomosis. The patient was free of neurological abnormalities and no recurrence of tumor was found during a 2-year follow-up period. CONCLUSIONS: Revascularization is sometimes thought to be required for resection of craniospinal meningiomas even when they do not appear to encase the vertebro-basilar arterial system on preoperative MR imaging and cerebral angiograms. In the present case, dissection of the PICA from the tumor was attempted, but was difficult due to tight encasement of the PICA by the tumor.

Anastomosis, Surgical↗
PubMed1998

Cervical infarction associated with vertebral artery occlusion due to spondylotic degeneration: case report.

Cases of cervical infarction with clearly documented evidence of the underlying aetiology and associated neuroradiological abnormalities have not been frequently reported. A rare case of cervical infarction caused by midvertebral artery occlusion due to spondylotic degeneration of the spine is described. The most probable aetiological factor affecting this disease entity, and the usefulness of magnetic resonance imaging in the detection of this rare lesion, are briefly discussed.

Aged↗
PubMed1998

Hemodynamic evaluation of the effect of percutaneous transluminal angioplasty for atherosclerotic disease of the vertebrobasilar arterial system.

The relationship between clinical improvement after percutaneous transluminal angioplasty (PTA) and hemodynamic condition in vertebrobasilar insufficiency was evaluated in 43 patients between 45 and 86 years of age with clinically symptomatic atherosclerotic stenotic lesions in the posterior circulation. The 43 patients had a total of 51 stenotic lesions, including 17 in the first segment of the vertebral artery, 32 in the fourth segment of the vertebral artery, and two in the basilar artery. Angiography was performed and cerebral perfusion was measured with technetium-99m-hexamethyl-propyleneamine oxime single photon emission computed tomography before and after administration of 10 mg/kg acetazolamide prior to and more than 7 months after PTA. Mean stenosis was 81.3 +/- 7.4% before PTA, but only 41.5 +/- 17.4% at follow-up. Eighteen of the 24 patients with improved neurological condition after PTA had subnormal (< mean - 2 SDs) cerebral perfusion before PTA. Twenty of these 24 patients had subnormal vasodilatory response to administration of acetazolamide before PTA. Clinical improvement following PTA was noted in only one of the 12 patients with a single stenotic lesion of the first segment, but in 23 of the 31 patients with intracranial stenotic or multiple stenotic lesions. PTA in the posterior circulation is indicated for patients with atherosclerotic stenotic intracranial lesion or multiple stenotic lesions who have subnormal cerebral perfusion and low vasodilatory response to administration of acetazolamide.

Acetazolamide↗
PubMed1997

Distribution of intraarterially administered papaverine in endovascular treatment of delayed cerebral vasospasm.

The distribution of selectively administered papaverine was determined in nine patients with delayed cerebral vasospasm in the territories of the anterior (ACA) and/or middle cerebral arteries (MCA) secondary to aneurysmal subarachnoid hemorrhage by simultaneous infusion with technetium-99m-hexamethyl-propyleneamine oxime (99mTc-HMPAO). Four of the nine patients had a ruptured anterior communicating artery aneurysm, four had an internal carotid artery aneurysm, and the remaining one had a MCA aneurysm. Trapping of anterior communicating artery was carried out in one case and clipping of aneurysms in other eight cases. Neurological deterioration with hemiparesis, paraparesis, and/or somnolence appeared between postsurgical Days 8 and 13 due to delayed cerebral vasospasm in all patients. Intraarterial infusion of 40 mg of papaverine containing 37 MBq of 99mTc-HMPAO was performed from the C1 segment in seven of the nine patients and from the C4 segment in the other two patients. 99mTc-HMPAO was distributed in the territories of the ACA and MCA in the two patients who were treated with intraarterial infusion of papaverine from the C4 segment, but was distributed only to the territory of the ACA in four patients who were treated with intraarterial infusion of papaverine from the C1 segment at 1 ml/min. In contrast, 99mTc-HMPAO was distributed in the territories of the ACA and MCA in the three patients who were treated with papaverine from the C1 segment at 2 ml/min, although most 99mTc-HMPAO was distributed in the territory of the ACA. Vasospasm of the ACA can be treated by intraarterial infusion of papaverine from the C1 segment at 1 ml/min when selective catheterization to the ACA is difficult to perform.

Adult↗
PubMed1997

Rete mirabile in humans--case report.

Carotid rete mirabile is a physiological vascular network between the external carotid and internal carotid systems present in some vertebrate species, but rarely observed in humans. We describe a 17-year-old girl with rete mirabile who presented with subarachnoid hemorrhage. Angiography disclosed the bilateral internal carotid arteries (ICAs) ended at the cavernous portion, and abnormal arterial networks visualized via the ICAs and the external carotid arteries in the paracavernous region. The distal ICAs were visualized via the abnormal arterial networks. After 18 years of follow-up she is leading a normal life without neurological problems. Rete mirabile in humans may present with hemorrhage or ischemic symptoms, but the prognosis appears to be good.

Adolescent↗
PubMed1997

[Regional cerebral hypoperfusion reduces the effect of rectal midazolam in children with Moyamoya disease].

To investigate the effect of regional cerebral blood flow on the effect of midazolam, we evaluated 99mTc-hexamethylpropylene-amine-oxime-single photon emission computed tomography (SPECT) in 37 cases of childhood moyamoya disease. They were divided into two groups according to the findings of SPECT; one group showed hypoperfusion in the bifrontal regions (n = 20), and the other did not (n = 17). Both groups received 1 mg.kg-1 of midazolam transrectally 30 min before the anesthesia induction and level of sedation was measured with six point scales. Significantly lower level of sedation score was recognized in the group that showed hypoperfusion in bifrontal regions (P < 0.05). Our finding may suggest that regional cerebral hypoperfusion may modify the sedative effect of midazolam in children with moyamoya disease.

Administration, Rectal↗
PubMed1997

[Anesthetic management of patients undergoing irrigation and drainage of chronic subdural hematoma--retrospective analysis of analgesia and sedation under locoregional anesthesia].

We retrospectively investigated the relationship between intraoperative hemodynamic variability and variables including patient background, anesthetic profile, and operative profile in 108 patients undergoing irrigation and drainage of chronic subdural hematoma under locoregional anesthesia. Patients were divided into two groups according to the degree of changes in mean arterial blood pressure (MAP) and heart rate (HR) during operation. Group A (n = 66) had MAP and HR changes < 20%, and Group B (n = 42) had MAP or HR changes > or = 20% of preoperative baseline values. Age was significantly higher in group B than Group A (mean +/- SD; 70 +/- 12 vs. 62 +/- 14 years, P < 0.01). In respect to additional anesthetic agents used (none; no additional anesthetic agents, enough; pentazocine > or = 0.3 mg.kg-1 and droperidol > or = 0.05 mg.kg-1, pentazocine > or = 0.5 mg.kg-1 or droperidol > or = 0.15 mg.kg-1, little; less than "enough"), ratio of "little" administered in Group B was significantly higher than that in Group A (64.3% vs. 37.9%, P < 0.05). These findings suggest that intraoperative hemodynamic variability under locoregional anesthesia in patients with chronic subdural hematoma is associated with age and insufficient use of hypnotic and/or analgesic agents.

Adjuvants, Anesthesia↗
PubMed1996

Selective angiography of the vertebral artery in the rabbit: technical note.

BACKGROUND: Selective angiography of the vertebral arteries has not been performed in rabbit models. We used a tracker-10 microcatheter for selective vertebral artery angiography. METHODS: Five Japanese male rabbits weighing 2.0 to 2.5 kg were used. The right femoral artery was identified and an 18-gauge Teflon catheter was introduced into the iliac artery. A Tracker-10 microcatheter was introduced through the 18-gauge Teflon catheter into the right vertebral artery under fluoroscopic guidance. RESULTS: Selective angiograms of the right vertebral artery were obtained using a bolus injection of 0.1 mL of iopamidol in all five rabbits. CONCLUSIONS: Selective vertebral artery angiograms could be obtained via the transfemoral route with the use of Tracker-10, and intraarterial selective administration of vasodilators will be achieved using our technique.

Animals↗
PubMed1996

Omental transplantation using a superficial temporal artery previously used for encephaloduroarteriosynangiosis.

BACKGROUND: Childhood moyamoya disease is a chronically progressive cerebrovascular occlusive disease affecting the territories of the anterior, middle, and posterior cerebral arteries. Surgery used in treatment of moyamoya disease to vascularize the brain include direct and indirect anastomoses. METHODS: Intracranial omental transplantation (OMT) was performed using a branch of the superficial temporal artery (STA) that had been used previously for encephaloduroarteriosynangiosis (EDAS) in five children with moyamoya disease. All five children continued to have paraparetic transient ischemic attacks (TIAs), urinary incontinence, and/or progressive mental retardation even after EDAS and/or STA-middle cerebral artery (MCA) anastomosis and encephalomyosynangiosis (EMS) to the territory of the MCA. Previously performed EDAS gave insufficient collaterals to the territory of the MCA in four of the five patients and sufficient collaterals to the territory of the MCA in the remaining patient. OMT was performed after stripping of a branch of the STA used in EDAS that gave insufficient collaterals to the brain in the former four patients; and the latter patient was performed using a parietal branch of the STA distal to the distal burr hole drilled in the previous EDAS. RESULTS: OMT resulted in marked improvement in neurologic conditions in all five patients. Four of the five patients suffered no TIAs postoperatively, while the remaining patient still had TIAs but at a markedly decreased frequency. CONCLUSIONS: In summary, OMT using a branch of the STA used in previously performed EDAS is required for patients with moyamoya disease who continue to manifest paraparesis, urinary incontinence, and/or progressive mental retardation even after multiple EDAS.

Brain↗
PubMed1996

Evaluation of time-dependent thresholds of cerebral blood flow and transit time during the acute stage of cerebral embolism: a retrospective study.

BACKGROUND: Neurons within the ischemic penumbra are thought to be in a potentially reversible state of ischemic challenge. One therapeutic approach that is being actively explored is the recovery of function of cells within the ischemic penumbra through endovascular recanalization of cerebral arteries occluded with embolus. The purpose of this study was to determine the time-dependent hemodynamic threshold for the prevention of irreversible ischemia in patients with acutely symptomatic internal and middle cerebral artery (MCA) embolism. METHODS: Thirty-six patients admitted within 6 hours of the onset of symptoms of acute cerebral ischemia, due to embolic occlusion of the major trunk of one of the arteries of the anterior cerebral circulation, were studied. On admission, both cerebral blood flow (CBF) and mean transit time (MTT) measurements were obtained following plain computed tomography (CT). All patients were treated by intraarterial administration of urokinase. MTT in the territory of the affected MCA divided by that in the territory of the unaffected MCA was defined as %MTT. RESULTS: A significant negative correlation was found between MTT and CBF. In patients with at least 19 mL/100 g/minute CBF and a maximum of 1.6 %MTT, no cortical infarction occurred whether or not recanalization was obtained. Cortical infarction did not appear in patients with 9 mL/100 g/minute residual CBF and infinite %MTT in whom recanalization was achieved within 2 hours of onset, in patients with 13 mL/100 g/minute residual CBF and 3.7 %MTT in whom recanalization was achieved within 2.5 hours of onset, and in patients with 14 mL/100 g/minute residual CBF and 2.8 %MTT in whom recanalization could be achieved within 3.5 hours of onset. CONCLUSIONS: CBF and MTT thresholds for conversion of reversible to irreversible ischemia can be rapidly determined by CT-based technologies. This type of information should be clinically relevant to guiding the management of patients with cerebral embolism.

Aged↗
PubMed1996

Preoperative and postoperative evaluation of cerebral perfusion and vasodilatory capacity with 99mTc-HMPAO SPECT and acetazolamide in childhood Moyamoya disease.

BACKGROUND AND PURPOSE: The results of long-term follow-up studies of cerebral perfusion and vasodilatory capacity following administration of acetazolamide after serial vascular reconstructions in 25 patients with childhood moyamoya disease are reported. METHODS: Cerebral perfusion was measured with 99mTc-hexamethylpropyleneamine oxime single-photon emission CT before and after IV administration of 10 mg/kg acetazolamide, which was performed both before and after vascular reconstruction by superficial temporal artery-middle cerebral artery anastomosis and encephalomyosynangiosis (first and second operations) and/or omental transplantation to the brain (third operation). RESULTS: Follow-up periods ranged between 12 and 24 months (mean +/- SD, 18.5 +/- 3.2 months) after the first operation. Repetitive transient ischemic attacks disappeared completely after serial vascular reconstructions in all patients. Before the first operation, cerebral perfusion in the territory of the middle cerebral artery on the side of initial operation was 83.9 +/- 4.7% and was significantly lower than that in the contralateral side (88.3 +/- 4.9%, n = 25; P < .0001, paired t test). Vasodilatory capacity on the side of the first operation was -18.4 +/- 2.5% and that on the contralateral side -14.4 +/- 2.1%. The former value was significantly lower than the latter value (n = 25; P < .0001, paired t test). After the first operation, cerebral perfusion and vasodilatory capacity on the side of initial operation were markedly improved, to 87.8 +/- 4.5% and -14.7 +/- 2.7%, respectively (n = 25; P < .0001, both cases, paired t test). Before the second operation, cerebral perfusion and vasodilatory capacity on the side of the second operation were 76.6 +/- 4.1% and -20.1 +/- 1.9%, respectively, and significantly lower than those before the first operation (n = 25; P < .0001, both cases, paired t test). Eight patients subsequently required bifrontal omental transplantation for repetitive paraparetic transient ischemic attacks after the second operation; they had low cerebral perfusion and vasodilatory capacity bilaterally in the territories of the anterior cerebral arteries (72.4 +/- 2.7% and -18.6 +/- 1.7%, respectively). After omental transplantation, both were significantly increased, to 81.9 +/- 3.4% and -11.8 +/- 1.9%, respectively (n = 25; P < .0001, both cases, paired t test). CONCLUSIONS: Hemodynamic compromise existed in patients with childhood moyamoya disease and was a major cause of development of ischemic symptoms. Regions in which hemodynamic compromise was present could be determined by measuring regional cerebral perfusion and vasodilatory capacity.

Acetazolamide↗
PubMed1995

Traumatic arteriovenous fistula treated by superselective embolisation with microcoils: case report.

A 27-year-old man with a traumatic direct dural arteriovenous fistula (DAVF) was treated using embolisation microcoils. He had suffered blunt trauma to the head while drunk and was aware of no neurological deficit. A few days after the accident, however, he noticed a bruit in the right temple. Angiography demonstrated a direct DAVF fed by the right middle meningeal artery and draining into a right temporal dural vein and the ipsilateral cavernous sinus. A Tracker-18 catheter was passed without difficulty through the fistula and the draining vein was then embolised from distal to proximal with microcoils, and finally the fistula was occluded with microcoils, resulting in total obliteration of the fistula. Immediately after the embolisation, the patient could no longer hear the bruit. Thus, when a microcatheter can be introduced into the draining vein, microcoils can be used as emboli in the treatment of direct DAVF.

Adult↗
PubMed1995

An intra-arterial electrode for intracranial electro-encephalogram recordings.

A new method for intracranial monitoring of brain electrical activity by means of an intra-arterial guide wire as electrode is described. We carried out intracranial electro-encephalography (EEG) using an insulated Seeker Lite-10 guide wire 18 times in 14 patients: ten times in 6 patients with cerebral arteriovenous malformation (AVM) before embolization, and another 8 times in 8 patients with epilepsy. In all cases, a 2-5 times stronger high voltage potential EEG compared with scalp EEG could be recorded. In 3 patients with complex partial epilepsy, intra-arterial (IA) EEG was recorded under subdural strip electrode monitoring, and IAEEG at the sphenoidal portion of the middle cerebral artery was compared with subdural electrode recordings. Frequent interictal spike discharges recorded with subdural electrodes in the lesional medial temporal lobe were simultaneously visible on IAEEG recording. This method is equivalent to that using a semi-invasive electrode, but ECoG recording can be performed at angiography. IAEEG is a method of electrode recording that has the possibility of clinical application.

Adolescent↗
PubMed1995

Anastomosis of occipital artery to posterior cerebral artery with interposition of superficial temporal artery using occipital interhemispheric transtentorial approach: case report.

BACKGROUND: Superficial temporal artery (STA)-superior cerebellar artery (SCA) anastomosis, and STA-posterior cerebral artery (PCA) anastomosis are considered suitable as surgical procedures for the treatment of patients with significant stenosis or occlusion in the rostral portion of the basilar artery and patients with significant stenosis or occlusion of the posterior cerebral artery, respectively. However, several authors have reported frequent and serious complications of these surgical procedures, including temporal lobe retraction edema and hematoma. In this study, we introduce a new surgical revascularization using an occipital interhemispheric transtentorial approach for the treatment of severe stenosis of the rostral portion of the basilar artery. CASE REPORT: A 47-year-old man with hypertension noted the sudden onset of nuchal pain followed by vertigo, diplopia, drunken gait, and motor weakness on his right side. Angiography performed on the day of the onset disclosed severe stenosis of the basilar artery. The stenotic portion extended just distal to the anterior-inferior cerebellar artery (AICA) to just proximal to the SCA, and in addition, a pseudolumen was visualized just distal to the left AICA. The patient underwent right occipital artery (OA) to left PCA anastomosis with interposition of the STA using an occipital interhemispheric transtentorial approach. Marked improvement in dysarthria, diplopia, ataxia gait, and visual disturbance were noted and he was able to walk without aid 3 days after operation. A postoperative angiogram of the right OA obtained 25 days after operation demonstrated visualization of the left PCA via the anastomosed OA and STA graft. CONCLUSIONS: OA-PCA anastomosis with interposition of STA graft using an occipital interhemispheric transtentorial approach can be substituted for STA-SCA anastomosis and STA-PCA anastomosis for treatment of stenosis/occlusion of the rostral portion of the basilar artery.

Anastomosis, Surgical↗