PubMed Health⌕ Search

Biomedical subjects

G M Nesbit

Publications and source records attributed to G M Nesbit.

At least 19 recordsLinked to original sources
PubMed2001

Intra-arterial thrombolysis for acute ischemic stroke.

Intra-arterial thrombolysis is a maturing treatment for acute thromboembolic stroke that shows promise in restoring cerebral blood supply. Reviewed evidence suggests that intra-arterial treatment has a longer window for treatment than intravenous t-PA and does improve outcome. A favorable outcome is dependent on careful patient selection aimed at avoiding intracranial hemorrhage. This article describes features to evaluate for patient selection and highlights factors along the treatment algorithm to maximize success.

Acute Disease↗
PubMed2001

Does reversal of ischemia on diffusion-weighted imaging reflect higher apparent diffusion coefficient values?

This study investigated whether ischemia on diffusion-weighted imaging (DWI) that reverses has higher apparent diffusion coefficients (ADCs). A patient treated with thrombolytics was evaluated with serial magnetic resonance imaging studies before treatment, at 3 and 14 days and at 4 weeks. A 100.01-cm3 left frontoparietal stroke on baseline DWI was only 18.11 cm3 (18%) on 4-week fluid attenuated inversion recovery. The mean ADC was 7.43 x 10(-3) mm2/s in the 6 regions that reversed and 7.31 x 10(-3) mm2/s in the 6 regions that persisted (P < .036). With thrombolytic treatment, large ischemic lesions on DWI may reverse, and these areas display higher mean ADCs.

Brain Ischemia↗
PubMed1999

Cavernous sinus sampling is highly accurate in distinguishing Cushing's disease from the ectopic adrenocorticotropin syndrome and in predicting intrapituitary tumor location.

Inferior petrosal sinus sampling (IPSS) is used to distinguish pituitary Cushing's disease from occult cases of the ectopic ACTH syndrome, but is limited in that it requires the use of ovine CRH (oCRH) and is not highly accurate at predicting the intrapituitary location of tumors. This study was designed to determine whether cavernous sinus sampling (CSS) is as safe and accurate as IPSS, whether CSS can eliminate the need for oCRH stimulation, and whether CSS can accurately predict the intrapituitary location of tumors. Ninety-three consecutive patients with ACTH-dependent Cushing's syndrome were prospectively studied with bilateral, simultaneous CSS before and after oCRH stimulation. Prediction of a pituitary or ectopic ACTH source was based on cavernous/peripheral plasma ACTH ratios. Intrapituitary tumor location was predicted based on lateralization (side to side) ACTH ratios. These predictions were compared to surgical outcome in the 70 patients who had surgically proven pituitary (n = 65) or ectopic (n = 5) disease. CSS distinguished pituitary Cushing's disease from the ectopic ACTH syndrome in 93% of patients with proven tumors before oCRH administration and in 100% of patients with proven tumors after oCRH. It was as safe and efficacious as published IPSS results. CSS accurately predicted the intrapituitary lateralization of the tumor in 83% of all patients and 89% of those patients with good catheter position and symmetric venous flow. CSS is as safe and accurate as IPSS for distinguishing patients with pituitary Cushing's disease from those with the ectopic ACTH syndrome. In addition, CSS appears to be superior to IPSS for predicting intrapituitary tumor lateralization.

ACTH Syndrome, Ectopic↗
PubMed1999

Extensive arachnoid ossification with associated syringomyelia presenting as thoracic myelopathy. Case report and review of the literature.

The authors present the case of progressive thoracic myelopathy caused by the extensive ossification of the arachnoid membrane and associated intramedullary syrinx. Based on their findings and results of the literature search, they describe a pathological basis for this rare condition, discuss its incidence and symptomatology, and suggest a simple classification for various types of the arachnoid ossification. They also discuss the magnetic resonance imaging features of arachnoid ossification and associated spinal cord changes. The particular value of plain computerized tomography, which is highly sensitive in revealing intraspinal calcifications and ossifications, in the diagnostic evaluation of patients with a clinical picture of progressive myelopathy is emphasized.

Arachnoid↗
PubMed1999

Angiographic evaluation and correlative anatomy.

This article provides a brief description of cerebral arterial angiographic anatomy with special attention given to the deep nuclear structures and collateral supply as it relates to acute ischemic stroke. Illustrative angiography cases with the CT or MRI are provided. Illustrative cases of differential diagnoses of stroke are also discussed.

Brain↗
PubMed1999

Intra-arterial thrombolysis for acute stroke.

Intra-arterial thrombolysis is a developing modality for the treatment of the acute stroke that shows promise in restoring cerebral arterial supply. The rationale for treatment via the intra-arterial route rather than intravenously rests on increased recanalization with preliminary evidence suggesting improved outcome. Successful treatment is due in part to selecting patients who are not at increased risk for unwanted sequelae, namely intracranial hemorrhage, based on clinical and imaging features. The authors describe some points of technique for the procedure with an emphasis on interpretation of findings to guide therapy and solve problems.

Acute Disease↗
PubMed1999

Other endovascular treatment strategies for acute ischemic stroke.

This article discusses the efforts being made to develop a safe, efficacious method of clot removal in the treatment of acute ischemic stroke. Four endovascular treatment strategies are discussed: mechanical clot disruption, endovascular thrombectomy, stents, and therapeutic carotid occlusion.

Acute Disease↗
PubMed1998

Current concepts on carotid artery-cavernous sinus fistulas.

With greater understanding of the pathophysiological mechanisms by which carotid artery-cavernous sinus fistulas occur, and with improved endovascular devices, more appropriate and definitive treatments are being performed. The authors define cartoid cavernous fistulas based on an accepted classification system and the signs and symptoms related to these fistulas are described. Angiographic evaluation of the risk the lesion may pose for precipitating stroke or visual loss in the patient is discussed. The literature on treatment alternatives for the different types of fistulas including transvenous, transarterial, and conservative management is reviewed.

Journal Article↗
PubMed1998

Endovascular treatment of traumatic dural sinus thrombosis: case report.

OBJECTIVE: Dural sinus thrombosis has rarely been associated with closed head injury. We present a unique case involving the use of endovascular thrombolysis in the treatment of traumatic dural sinus thrombosis, which has not been reported. CLINICAL PRESENTATION: A 20-year-old male patient suffered a severe closed head injury while skiing. He developed refractory elevated intracranial pressure requiring barbiturate coma. Angiography demonstrated thrombosis of the dominant right transverse and sigmoid sinuses, with partial thrombosis of the superior sagittal sinus. Urokinase was administered via a microcatheter within the thrombus as a bolus of 250,000 units and then as a continuous infusion of 60,000 to 100,000 units per hour for 48 hours. The patient was maintained in a barbiturate coma and heparinized. Serial angiography was performed to assess the sinus patency and efficacy of thrombolysis. RESULTS: After 48 hours of thrombolysis, angiography demonstrated normal patency of the superior sagittal, right transverse, and right sigmoid sinuses. The intracranial pressure decreased after thrombolysis and was manageable with conventional techniques. Within 48 hours of the completed thrombolysis, the barbiturates were withdrawn and the patient's neurological status rapidly improved until the time of discharge 2 weeks later. DISCUSSION AND CONCLUSION: This case documents a rare instance of traumatic dural sinus thrombosis resulting from a closed head injury. In addition, endovascular thrombolysis resulted in subsequent opening of the dural sinuses and effective intracranial pressure management, despite the presence of a hemorrhagic contusion. Heparin was effective in maintaining sinus patency and was used safely in conjunction with urokinase in this setting of head injury.

Accidental Falls↗
PubMed1998

The role of angioplasty in the treatment of cerebrovascular disease.

Percutaneous transluminal angioplasty (PTA), an established treatment of arterial stenosis in coronary, renal, and other peripheral sites, is being applied to the cerebrovascular territory with greater frequency. Early results suggest that PTA may be safe and efficacious in the treatment of extracranial arterial stenosis secondary to atherosclerosis and fibromuscular dysplasia. PTA is also being used with promising results in treating symptomatic intracranial arterial stenosis from atherosclerosis. This review examines PTA in the treatment of cerebrovascular disease, current indications, and results.

Angioplasty↗
PubMed1998

Clinical and angiographic outcomes, with treatment data, for patients with cerebral aneurysms treated with Guglielmi detachable coils: a single-center experience.

OBJECTIVE: The purpose of this report is to provide the most detailed treatment and outcome data currently available in the literature, to allow for the further evaluation of Guglielmi detachable coils (GDC) as an appropriate treatment option for patients with cerebral aneurysms. METHODS: During a period of 4.5 years, 74 patients with intracerebral aneurysms were treated with GDC in the Department of Neurosurgery at Oregon Health Sciences University. A comprehensive retrospective and prospective analysis of these patients was performed, to assess the overall angiographic and clinical outcomes for these patients. RESULTS: Seventy-seven aneurysms were treated, with an average angiographic follow-up period of 1.4 years. Initially, 40% of aneurysms exhibited complete (100%) occlusion, 52% near complete (90-99%) occlusion, and 8% incomplete (<90%) occlusion. The average clinical follow-up period was 2.2 years. For unruptured aneurysms, 85% of patients returned to independent status. Of patients of Hunt and Hess Grade I/II status, 81% were independent; of patients of Grade III status, 100% were independent; and, of patients of Grade IV/V status, 50% were independent. The procedure-related morbidity rate was 9.1%, with a 7.8% risk of death from aneurysm perforation, stroke, or delayed hemorrhage. No completely occluded aneurysm hemorrhaged after GDC treatment (follow-up period, 1.9 yr). Of near complete occlusions, 2.6% hemorrhaged after embolization, at a rate of 1.4%/yr (follow-up period, 1.9 yr). CONCLUSION: This study details long-term clinical outcomes after GDC treatment and describes factors affecting the need for retreatment. Although complete anatomic cure was not obtained in all cases and the long-term protection from subarachnoid hemorrhage remains to be determined, these data indicate that GDC are a safe and efficacious treatment for cerebral aneurysms.

Activities of Daily Living↗
PubMed1998

The use of electrolytically detachable coils in treating high-flow arteriovenous fistulas.

BACKGROUND AND PURPOSE: High-flow arteriovenous fistulas (AVFs) are commonly treated by using an endovascular approach with a variety of materials. The use of a Guglielmi electrolytically detachable coil (GDC) provides the ability to reposition or remove the coil if its position is not optimal and may minimize the risk of coil migration or distal embolization. This study reports our experience in using these coils alone or in combination with other materials in the treatment of intracranial and cervical high-flow fistulas. METHODS: Twelve patients with AVFs were treated with GDCs via the transvenous or transarterial-transfistulous routes. The six dural AVFs treated transvenously were also treated transarterially, and the GDCs were combined with fibered coils in three of these patients and in two other patients with pial AVFs. All patients have been clinically followed up for 12 to 48 months (mean, 28 months). RESULTS: Angiographic obliteration was obtained in all 12 patients. The fistulas have remained closed in 11 patients, as ascertained by angiographic confirmation in two patients and by clinical examination in nine patients. The one patient with recurrence experienced neurologic improvement and refused further treatment. GDCs required repositioning before detachment in seven patients, and no migration occurred after detachment. CONCLUSION: GDCs are useful for the treatment of high-flow AVFs. They afford more control in the placement of coils and may provide an anchoring point for more thrombogenic materials.

Adolescent↗
PubMed1997

Endovascular management of hemorrhage in patients with head and neck cancer.

OBJECTIVE: To present selective endovascular embolization as a therapeutic alternative to surgical ligation in the management of hemorrhage in patients with head and neck squamous cell carcinoma. DESIGN: Retrospective chart review of patients with head and neck cancer and significant hemorrhage who were treated with selective endovascular embolization. SETTING: A university medical center. PATIENTS: A total of 12 patients, aged 26 to 72 years, with 13 episodes of hemorrhage were treated at Oregon Health Sciences University, Portland, between November 1991 and January 1996. INTERVENTION: All patients underwent angiography with selective endovascular embolization at the interventional radiology suite using a combination of endovascular balloons, platinum coils, and microparticles. OUTCOME MEASURES: All charts were reviewed for diagnosis, treatment, factors that may have contributed to hemorrhage, bleeding site, therapeutic measures, control of hemorrhage, postembolization course, complications, and number of hospital days. RESULTS: The cause of the bleeding was tumor in 5 patients, pharyngocutaneous fistula in 4 patients, radiation necrosis in 3 patients, and postoperative complication in 1 patient. Bleeding arose from the common carotid artery in 4 patients, external carotid artery and its branches in 8 patients, and internal jugular vein in 1 patient. Hemorrhage was successfully controlled in all patients; a permanent left-sided hemiplegia and facial weakness developed in 1 patient. There were no recurrences of hemorrhage. All patients were discharged from the hospital. CONCLUSION: Angiography with selective embolization is a safe and effective alternative to surgical ligation for control of hemorrhage in patients with squamous cell carcinoma of the head and neck.

Adult↗
PubMed1997

2D time-of-flight MR angiography using concatenated saturation bands for determining direction of flow in the intracranial vessels.

We prospectively studied 15 patients to assess 2D time-of-flight (TOF) magnetic resonance angiography (MRA) with concatenated saturation bands for determining the direction of intracranial blood flow. This MRA sequence was compared to T2-weighted spin-echo MRI, 3D-TOF MRA, and intra-arterial angiography (IAA) as regards demonstration of vessels and determination of the direction of flow in the circle of Willis and its branches. The 2D-TOF MRA sequence demonstrated flow in 98.5% vessel segments identified on IAA, 3D-TOF demonstrating 92% and spin-echo images 77%. The direction of flow shown on the 2D-TOF sequence was correct in 94% when compared to conventional angiography, the remaining six segments not demonstrating flow. In ten patients, the flow abnormalities demonstrated by this MRA technique provided clinical information similar to that of conventional angiography in nine, but it was incomplete in three, and misleading in one. Slow retrograde flow in ophthalmic artery collaterals and differentiation of arteries and veins presented some problems. 2D-TOF MRA with concatenated saturation bands provides flow direction information using widely available, easily applicable TOF techniques, and can be a useful adjunct to MRI and MRA if information on flow direction is needed.

Arteries↗
PubMed1997

Rotational vertebral artery occlusion: a mechanism of vertebrobasilar insufficiency.

OBJECTIVE: Symptomatic dynamic changes in blood flow secondary to vertebral artery compression with rotational head motion are evaluated in a series of patients as a cause for posterior circulation transient ischemic attacks. These cases are classic examples of rotational vertebral artery occlusion and allow for the discussion of the anatomic basis, angiographic features, and treatment options. ILLUSTRATIVE CASES: In our series, symptoms of vertebrobasilar insufficiency were reproducible with rotational head movement. Compression of the vertebral artery was demonstrated angiographically. The correct site of occlusion of the vertebral artery was apparent only by dynamic angiography with progressive head rotation. All of the patients presented in the illustrative cases had occlusion at the C2 level; however, one patient had been previously misdiagnosed and another had an additional site of occlusion. The anatomic course of the vertebral artery is described in addition to the sites of rotational occlusion. CONCLUSION: Rotational vertebral occlusion is an important cause of vertebrobasilar symptoms, which may lead to permanent neurological deficit if left undiagnosed. Dynamic angiography is the established method of diagnosis. Great care must be taken to avoid misdiagnosing the site of occlusion or missing a second occlusive site. For this reason, it is crucial to have a thorough understanding of the anatomic course of the vertebral artery and the muscular and tendinous insertions, which may cause rotational occlusion. The decision for treatment must be based on the site of occlusion as well as the assessment of the patient as a surgical candidate. A review of the literature reveals that surgical treatment is effective and must be considered to avoid further morbidity.

Adult↗
PubMed1996

Direct carotid cavernous fistula after trigeminal balloon microcompression gangliolysis: case report.

OBJECTIVE AND IMPORTANCE: Percutaneous gangliolysis procedures may rarely be associated with vascular complications. There are three reported cases of carotid cavernous fistulas occurring after percutaneous microcompressive trigeminal gangliolysis. This is the only reported case of this complication associated with microcompression gangliolysis. CLINICAL PRESENTATION: A 78-year-old woman was referred to our institution with a history of abrupt onset of left-sided bruit, proptosis, chemosis, and diplopia after a percutaneous retrogasserian microcompression. INTERVENTION: Cerebral angiography revealed a large left direct carotid cavernous fistula. Attempts at balloon embolization were unsuccessful, and the lesion was ultimately cured by transarterial and transvenous coil embolization. CONCLUSION: Follow-up examination revealed no evidence of bruit or neurological deficit. This report highlights a unique complication of balloon gangliolysis and describes coil embolization of the fistula as the mode of treatment.

Aged↗