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Biomedical subjects

F Viñuela

Publications and source records attributed to F Viñuela.

At least 127 records · Page 7Linked to original sources
PubMed1985

CT of multiple sclerosis: reassessment of delayed scanning with high doses of contrast material.

A prospective study involving 87 patients was carried out to evaluate the necessity for a high dose of contrast material in addition to delayed computed tomographic (CT) scanning for optimal detection of the lesions of multiple sclerosis in the brain. In patients with either clinically definite multiple sclerosis or laboratory-supported definite multiple sclerosis, CT scans were obtained with a uniform protocol. Lesions consistent with multiple sclerosis were demonstrated on the second scan in 54 patients. In 36 of these 54 patients, the high-dose delayed scan added information. These results are quite similar to those of a previous study from this institution using different patients, in whom the second scan was obtained immediately after the bolus injection of contrast material containing 40 g of organically bound iodine. The lack of real difference in the results of the two studies indicates that the increased dose, not just the delay in scanning, is necessary for a proper study.

Brain Diseases↗
PubMed1985

Stenotic and occlusive disease of the venous drainage system of deep brain AVM's.

Angiograms obtained prior to treatment in 53 cases of deep-seated cerebral arteriovenous malformations (AVM's) were retrospectively analyzed with particular attention to the topography of the AVM nidus and the venous drainage. The location of the lesion was determined by a combination of angiography and computerized tomography. Twenty-seven AVM's involved the basal ganglia and thalamus, 12 were located in the corpus callosum, six were intraventricular, and eight involved the mesencephalon and brain stem. Forty-one patients (77.3%) presented with intracranial hemorrhage. Vessel wall irregularities and/or stenosis of the system of the vein of Galen were observed in 14 cases, and occlusion of the deep venous system was present in seven cases. These AVM's showed numerous collateral venous pathways through enlarged medullary and cortical regional veins. There was dominant participation of the basal vein of Rosenthal in all cases. Unique local hemodynamic factors produced by the convergence of the draining veins of the AVM's into the vein of Galen and straight sinus may lead to a higher incidence of stenosis and/or occlusion of the venous drainage. The relatively high incidence of intracranial hemorrhage in these deep-seated AVM's may suggest a relationship between an increased incidence of intracranial bleeding and impaired venous outlets.

Adolescent↗
PubMed1984

Clinico-radiological spectrum of giant supraclinoid internal carotid artery aneurysms. Observations in 93 cases.

A review of a series of 312 giant intracranial aneurysms treated at University Hospital in London, Ontario, showed that 93 of those aneurysms were located between the intracavernous portion and the bifurcation of the internal carotid artery. Sixty-five of those aneurysms were carotid ophthalmic, 12 were located in the internal carotid-posterior communicating-anterior choroidal artery regions and 16 involved the internal carotid artery bifurcation. For the majority, clinical presentation was related to the mass of the aneurysms and compression of surrounding structures such as visual pathways, ocular motor cranial nerves, the fifth nerve, and hypothalamic-pituitary axis. Fourteen patients presented with subarachnoid hemorrhage. Cerebral angiography, computed tomography and xenon inhalation studies of cerebral blood flow were the tools used to study the morphology of the aneurysm and dynamics of the circle of Willis.

Brain↗
PubMed1984

Vertebrobasilar occlusion therapy of giant aneurysms. Significance of angiographic morphology of the posterior communicating arteries.

The clinical and angiographic records were reviewed for 71 patients with giant aneurysms of the posterior circulation, who underwent therapeutic occlusion of the basilar artery or both vertebral arteries. This treatment is used when the aneurysm neck cannot be surgically clipped, and occlusion of the parent artery is performed to initiate thrombosis within the lumen. In these cases, collateral blood flow to the brain stem is supplied mainly by the posterior communicating arteries. Consequently, their angiographic morphology (patency, size, and number) is demonstrated as a preoperative indicator of whether the patient will be able to tolerate vertebrobasilar occlusion. Vertebral angiograms with carotid artery compression (the Allcock test) will often be needed to provide this information. The data relating posterior communicating artery morphology to clinical outcome in 71 cases of attempted vertebrobasilar occlusion are presented. The use and accuracy of carotid artery compression studies are also discussed. It is essential for the radiologist to supply the neurosurgeon with this valuable information in every case of giant posterior circulation aneurysm.

Basilar Artery↗
PubMed1984

Spontaneous carotid-cavernous fistulas: clinical, radiological, and therapeutic considerations. Experience with 20 cases.

Sixty-five carotid-cavernous fistulas were studied at University Hospital, London, Canada, from 1978 to 1982, 20 of which fulfilled the clinical and angiographic criteria of a spontaneous carotid-cavernous fistula. Of these 20 fistulas, 17 were unilateral, and three were bilateral. In 18 cases the angiographic findings were typical of an arteriovenous malformation (AVM), and in two a ruptured giant intracavernous aneurysm was found. These patients were treated according to whether they had a nonresolving or progressive cavernous sinus syndrome or deterioration of vision. The cavernous dural AVM's were treated with polyvinyl-alcohol and/or isobutyl-2-cyanoacrylate (IBCA) embolization of the external carotid artery blood supply. Two patients underwent postembolization surgical procedures. The detachable balloon technique was used to occlude the fistulas associated with the two giant ruptured intracavernous aneurysms and a small dural intracavernous AVM. Eight patients received no therapy; in two, spontaneous obliteration of the fistula occurred. Of the nine cavernous AVM's embolized with particles and/or IBCA, successful transvascular embolization was achieved in seven cases, and partial embolization followed by surgery in two cases. Successful balloon obliteration of the giant intracavernous ruptured aneurysm was obtained in two cases. In one patient, right hemiplegia with aphasia resulted from reflux of IBCA emboli through the artery of the foramen rotundum into the left middle cerebral artery.

Adolescent↗
PubMed1984

CT demonstration of hemiatrophy and fatty replacement of the tongue.

We report a patient in whom computed tomography was used to demonstrate denervation, hemiatrophy and fatty replacement of the tongue, secondary to lower motor neuron involvement of the hypoglossal nerve by a meningioma. This unusual finding has only been described once before.

Adipose Tissue↗
PubMed1983

Spinal cord size in syringomyelia: change with position on metrizamide myelography.

Change in the anteroposterior diameter of the cervical spinal cord was demonstrated on metrizamide myelography in 20 out of 40 cases of cervical syringomyelia. Twelve of these were normal-sized cords, four were small, and four enlarged. Comparable lateral cervical myelograms in the prone and supine positions were sufficient to show size change for normal-sized or small cords. Additional myelograms in the erect and Trendelenburg positions were necessary to show size change in enlarged cervical cords, especially with associated Chiari malformation. A localized change in cord size suggests syringomyelia. If the change in cord size is diffuse, then change less than 10% is not necessarily significant. In undiagnosed myelopathy, metrizamide myelography has the potential to detect unsuspected syringomyelia even when the cord is normal-sized or small. Myelographic study may also be useful as an adjunct to delayed computed tomographic studies.

Humans↗
PubMed1983

Peripheral aneurysms of the cerebellar arteries. Review of 16 cases.

True congenital peripheral aneurysms of the cerebral arteries are rare and may constitute a special group. The authors report on 16 cases of peripheral aneurysms of the cerebellar arteries; six of them arising from vessels feeding arteriovenous malformations (AVM's). The possible causative role of increased blood flow versus developmental factors in the frequent occurrence in cases of AVM of this otherwise rare type of aneurysm is discussed. In five of the six cases with AVM's (one dural and five parenchymal), the aneurysm rather than the AVM proved to be the source of the hemorrhage. The occurrence of spasm was in inverse proportion to the distance of the aneurysm from the main arteries. The surgical result was good in 11 cases. One patient with associated AVM died, and four patients had residual symptoms.

Adult↗
PubMed1983

Balloon occlusion of a spontaneous fistula of the posterior inferior cerebellar artery. Case report.

A case is reported of a large spontaneous right posterior inferior cerebellar artery fistula in which the patient presented with a right cerebellopontine (CP) angle and right cerebellar syndrome. The patient was successfully treated by balloon occlusion at the fistula site. The location of the arteriovenous fistula, the mass effect of its enlarged draining veins on the cerebellum and CP angle structures, and the simple therapeutic endovascular occlusion with a detachable balloon make this case unique.

Adult↗
PubMedDate not supplied

Development of a biologically active Guglielmi detachable coil for the treatment of cerebral aneurysms. Part I: in vitro study.

BACKGROUND AND PURPOSE: Stronger cellular adhesion on the surface of endovascular devices promotes accelerated healing of aneurysms. The purpose of this in vitro study was to study the cellular interaction on the surface of bioactive Guglielmi detachable coils (GDCs) after using the surface-modification technology, ion implantation. METHODS: Polystyrene (PS) dishes and platinum plates were used to simulate a GDC surface. They were treated with either simple collagen coating or collagen coating followed with ion implantation. Bovine endothelial cells (2-2.5 x 10(4) cells in 1 mL) were suspended in medium supplemented with 10% fetal bovine serum on the PS dishes or platinum plates. Five days after cell seeding, the strength of cell adhesion was evaluated by trypsin treatment and flow shear stress. The cell detachment from the PS and platinum surfaces was observed microscopically. RESULTS: Five days after cell seeding, both simple collagen-coated surfaces and collagen-coated ion-implanted surfaces showed uniform endothelial proliferation. After trypsin treatment, or under flow shear stress, stronger cell adhesion against chemical and flow shear stress was observed on the ion-implanted collagen-coated surface. In contrast, the endothelial cells were detached easily from the non-ion-implanted collagen-coated surface. CONCLUSION: Ion implantation in combination with protein coating improves the strength of surface cell adhesion when exposed to flow shear stress and proteolytic enzymes. Strong endothelial cell adhesion is reported to be important to achieve earlier endothelialization across the neck of an embolized aneurysm with bioactive GDCs. This new technology may improve long-term anatomic outcome in cerebral aneurysms treated with GDCs.

Animals↗
PubMedDate not supplied

Development of the biologically active Guglielmi detachable coil for the treatment of cerebral aneurysms. Part II: an experimental study in a swine aneurysm model.

BACKGROUND AND PURPOSE: Ion implantation is a surface-modification technology that creates a borderless surface on protein-coated platinum; this change in physical and chemical properties on the surface of Guglielmi detachable coils (GDCs) appears to enhance cell proliferation and adhesion. Our purpose was to evaluate the effect of ion implantation on GDCs in an experimental aneurysm model. METHODS: GDCs were coated with either type I collagen, fibronectin, vitronectin, laminin, or fibrinogen. Using He+ or Ne+ 1 x 10(14-15) ions/cm2, ion implantation was performed on these protein-coated GDCs (GDC-Is). A total of 56 experimental aneurysms were constructed microsurgically in the common carotid arteries of 28 swine. These experimental aneurysms were embolized with standard GDCs (n = 23), collagen GDC-Is (n = 11), vitronectin GDC-Is (n = 6), laminin GDC-Is (n = 4), fibrinogen GDC-Is (n = 6), and fibronectin GDC-Is (n = 6). The animals were sacrificed at day 14 after coil embolization. The physical properties of the new coils (friction on delivery, deployment into aneurysms, trackability, etc) and the development of tissue scarring and neoendothelium across the aneurysm's orifice were evaluated macroscopically and microscopically. RESULTS: No evidence of increased coil friction/stiffness was observed during delivery of GDC-Is through microcatheters in this aneurysm model. A more intense scar formation and neoendothelium at the neck of aneurysms were observed macroscopically when treated with GDC-Is. Significant differences in the proportion of neck coverage between standard GDCs (48.3% +/- 20.5%) and all GDC-I groups were observed (collagen GDC-I-89.4% +/- 14.9%, P < .01; vitronectin GDC-I-71.5% +/- 7.0%, P < .05; laminin GDC-I-76.5% +/- 11.0%, P < .05; fibrinogen GDC-I-74.8% +/- 13.9%, P < .05; fibronectin GDC-I-87.5% +/- 15.0%, P < .01). Light microscopy showed a well-organized fibrous tissue bridging the aneurysm's neck when using GDC-Is, whereas only a fibrin-like thin layer covered the standard GDC surfaces. CONCLUSION: GDC-Is indicated a more intense inflammatory response in the aneurysm body and dome and faster re-endothelial coverage of the neck of the aneurysm. This accelerated histologic response may decrease the chances of coil compaction and aneurysm recanalization. This technology may improve anatomic and clinical outcomes in patients harboring intracranial aneurysms.

Animals↗
PubMedDate not supplied

Dural arteriovenous fistula in children: endovascular treatment and outcomes in seven cases.

BACKGROUND AND PURPOSE: Dural AVF is a vascular anomaly that rarely occurs in children and is best treated by endovascular embolization. We report our experience using various endovascular embolization techniques in the treatment of dural AVF in a pediatric population. METHODS: Seven children with angiographically proven dural AVF were treated with endovascular embolization using microcoils, N-butylcyanoacrylate, detachable balloons, and/or silk suture. All imaging studies, embolization procedures, and patient charts were retrospectively reviewed. RESULTS: Seven children had been treated for dural AVF at our institution since 1987. Three newborns presented with congestive heart failure. Four older children (10 months-10 years) presented with signs referable to venous hypertension, including seizures, hydrocephalus, and proptosis. Embolization approaches included transarterial, transvenous, and direct puncture after neurosurgical exposure of a dural sinus. The number of embolizations ranged from 1 to 13 sessions per patient. All patients experienced symptomatic improvement after each embolization session. The three newborns showed marked improvement in cardiac function that allowed discharge to home. Clinical follow-up ranged from 3 weeks to 9 years (mean, 4.1 years). Two children with partially embolized dural AVF died, and one was lost to follow-up. Four children are alive after complete embolization of their dural AVF; two are developmentally normal, and two have mild developmental delay. CONCLUSION: Endovascular embolotherapy is the current treatment of choice for dural AVF. Embolization therapy may be life saving in the setting of cardiac failure and curative in cases of small or simple fistulae. Multiple, complex dural AVF are usually not curable, and treatment is aimed at symptomatic relief. Treatment strategies focus on the location and/or complexity of the fistula, the patient's clinical status, and the neurologic prognosis.

Central Nervous System Vascular Malformations↗
PubMedDate not supplied

Delayed venous occlusion following embolotherapy of vascular malformations in the brain.

PURPOSE: To describe the nature and features of delayed venous thrombosis following embolization of arteriovenous fistulae. METHODS: Retrospective review of the available clinical history, details of embolization procedures, and results of follow-up angiography were carried out on all embolization procedures performed on high-flow vascular malformations of the brain done at our institution since 1987. RESULTS: Four patients were identified who had delayed (greater than 1 week) venous thrombosis/occlusion after embolization of the malformation associated with neurologic complications. Two patients had arteriovenous fistula and two had vein-of-Galen malformations. These patients had no untoward embolization of the venous outlet as a cause of the venous occlusion. CONCLUSIONS: It is postulated that thrombosis in the arteriovenous fistula group was induced by conversion (due to embolization) of a patulous high flow venous outlet into a slow flow system; in the vein-of-Galen group, the occlusion was thought to be due to high-flow venopathy.

Adult↗
PubMedDate not supplied

Transvenous treatment of spontaneous dural carotid-cavernous fistulas using a combination of detachable coils and Onyx.

Three patients with spontaneous dural carotid-cavernous fistulas were treated by using a combination of detachable coils and Onyx liquid embolic agent. Cavernous sinus was accessed via the superior ophthalmic vein or inferior petrous sinus approach. In all cases, a complete angiographic closure of the fistulas was achieved with full recovery from neuro-ophthalmologic symptoms. This report suggests that the controlled and excellent penetration of Onyx is superb for blocking the intricate communication of dural carotid-cavernous fistulas.

Aged↗
PubMedDate not supplied

Angiographic diagnosis and management of head and neck schwannomas.

Schwannomas are tumors derived from nerve sheath cells, which are often located in the head and neck, including the CNS. Although a definitive vascular pattern has been previously characterized for these lesions, preoperative embolization of the more vascular schwannomas has not been described. In a review of eight patients with schwannomas who underwent angiography at our institution since 1987, a characteristic vascular pattern became apparent that helped distinguish these lesions from other lesions of the head and neck. The lesions were moderately vascular with tortuous tumor vessels. Scattered, small puddles of contrast medium seen in the mid-arterial, capillary, and venous phases were believed to be characteristic of these lesions. Multiple feeding vessels were noted in all but one case, but these were only minimally enlarged. No arteriovenous shunting or vascular encasement was identified. Six of eight lesions were embolized with significant devascularization and no morbidity or mortality. In patients with head and neck tumors whose angiographic findings include a pattern of moderate hypervascularity, tortuous tumor vessels, and, in particular, scattered contrast puddles without arteriovenous shunting or vascular encasement, schwannoma should be suspected. Embolization is a useful and safe presurgical adjunct in the treatment of vascular schwannomas.

Adult↗