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Biomedical subjects

A J Fox

Publications and source records attributed to A J Fox.

304 records · Page 17Linked to original sources
PubMedDate not supplied

Preoperative embolization of brain AVMs with isobutyl-2 cyanoacrylate.

The role of embolization in the management of brain arteriovenous malformations remains controversial. The benefits of embolization alone are not clear and surgical removal may be technically difficult or impossible in many cases. In an attempt to facilitate surgical removal, we performed preoperative embolization in 15 cases using a mixture of isobutyl-2 cyanoacrylate and glacial acetic acid. In one case, a mixture of polyvinyl alcohol particles, microfibrillar collagen, and 30% ethanol was used. In 10 of these cases the surgeon felt that the embolization significantly aided the operative removal by decreasing blood loss, reducing the size of draining veins, and removing portions of the nidus itself. In no patient did the embolization result in an unanticipated significant neurologic deficit. The major role for embolization in the management of brain arteriovenous malformations may be as an aid to surgical removal.

Adult↗
PubMedDate not supplied

A comparison of iopamidol and iohexol in cerebral angiography.

Iopamidol and iohexol, the new nonionic low-osmolality contrast agents, have both been shown to be safe, effective, and better tolerated than conventional ionic agents for cerebral angiography. In this randomized, double-blind study involving 40 patients, these two agents were compared for adverse effects, radiographic quality, and patient tolerance. No significant differences were observed in 220 injections. Because we found iopamidol and iohexol to be equally safe and effective for cerebral angiography, the choice of which contrast agent to use should be based on other considerations.

Adult↗
PubMedDate not supplied

Unruptured intracranial arteriovenous malformations do cause mass effect.

Sixty patients with clinically unruptured intracranial arteriovenous malformations were studied with high-resolution computed tomography. In 33, local and distant mass effects were evidenced by compression, distortion, and displacement of normal anatomic structures by the malformation, its afferent and efferent vessels, and the surrounding edema.

Brain Edema↗
PubMedDate not supplied

Rolandic arteriovenous malformations: improvement in limb function by IBC embolization.

Three patients with arteriovenous malformations in the rolandic region and significant limb deficit showed virtually complete functional recovery after awake operative embolization of most of the malformations using isobutyl-2 cyanoacrylate. Two of these patients, with functionally useless hands, had sustained the deficits months earlier as the result of a specific brain-damaging event: one as a result of surgery and the other as a result of a hemorrhage. Both of these showed significant return of function during the awake operative embolization procedure. The other patient had had progressive leg weakness over a 2 year period. The theory of steal phenomenon as an explanation for progressive neurologic deficits in association with large arteriovenous malformations must be extended to explain apparently stable deficits after some brain trauma (surgery or hemorrhage). These results suggest that some patients with arteriovenous malformations and without clinical deficits who are near a critical level of "near ischemia" may be thrown out of balance by an acute interceding event.

Adolescent↗
PubMedDate not supplied

Delayed metrizamide CT enhancement of syringomyelia: postoperative observations.

Delayed metrizamide computed tomography (CT) was performed both preoperatively and postoperatively in 11 syringomyelia patients. Change of syrinx size between the studies was easily assessed on CT. The morphologic change of the syrinx gave useful information about its continuity. One of our cases had reoperation as a result of this CT information. All cases with Chiari I malformation still showed filling of the syrinx cavity by metrizamide after posterior fossa decompression and obex plugging. This supports the idea that the abnormal fluid circulation maintaining syringomyelic cavities is more than just the flow through the obex to the central canal but may also be from fluid passage through the cord substance.

Humans↗
PubMedDate not supplied

Stenosis of afferent vessels of intracranial arteriovenous malformations.

Four women are described with stenoses of the feeding arteries to cerebral arteriovenous malformations. These stenoses were hemodynamically significant in that the nidus malformations filled late in the arterial phase of angiography and the draining veins did not fill much earlier than the usual venous phase. In two of these patients, who were referred for possible embolization, the stenosis served as an impediment to balloon navigation in the feeding vessel in one and served as a partial contraindication to embolization in the other. It is possible that if these stenoses progress, they may lead to thrombosis of the arteriovenous malformations.

Adult↗
PubMedDate not supplied

Two different calibrated-leak balloons: experimental work and application in humans.

Two different types of latex calibrated-leak balloon catheters have been developed. One consists of a Teflon catheter with a detachable latex balloon and is used to embolize branches of the external carotid artery. The other consists of a Silastic catheter with a nondetachable latex balloon and is used to embolize brain arteriovenous malformations. An experimental model and animal experiments have determined the best conditions for safe and reproducible embolization with isobutyl-2 cyanoacrylate (IBC-2). Selective catheterization of branches of external carotid, middle cerebral, anterior cerebral, and posterior cerebral arteries in humans is facilitated, and embolization with IBC-2 has been achieved with these balloon catheters.

Adolescent↗
PubMedDate not supplied

Complete myelography with metrizamide.

Thorough myelography of the entire spinal cord including the foramen magnum region can be accomplished consistently and promptly after metrizamide injection via lumbar or lateral cervical puncture. When lumbar puncture is used the patient's torso is oblique, but the neck is prone and straight and the table is tilted 20 degrees head-down to allow direct cervical filling with contrast material. Each region is filmed in several projections, the patient being turned gently from the prone cervical to the supine thoracic position. Of 100 cases without block studied in this way, all had adequate cervical and foramen magnum films. In only five was the contrast material too dilute to show the edges of the spinal cord well and the subarachnoid sac adequately in the thoracic region. In 29 patients, there were mild side effects not requiring medication, while 20 had side effects of a more moderate to severe nature. No seizures were encountered. Metrizamide proved a convenient, efficient, and acceptable contrast medium for myelography when a study of the entire spinal cord is indicated.

Cauda Equina↗
PubMedDate not supplied

Delayed CT metrizamide enhancement of syringomyelia secondary to tumor.

Six cases of syringomyelia associated with intramedullary tumor were examined by metrizamide myelography and delayed computed tomography. All cases showed opacification of syringomyelic cavities 7-24 hr after myelography. This finding suggests that metrizamide can pass through the cord substance from the subarachnoid space into a syrinx cavity in noncommunicating types of syringomyelia. It supports the theory of transneural passage of fluid as part of the origin of such cavities. These cases also support the thesis that, in patients with cord cavities, tumor can be excluded only if the cavity is demonstrated within all areas of cord enlargement.

Adult↗
PubMedDate not supplied

Dominant-hemisphere arteriovenous malformations: therapeutic embolization with isobutyl-2-cyanoacrylate.

Embolization treatment of 16 patients with dominant-hemisphere arteriovenous malformations (AVMs) is described. This group was selected from 50 patients with brain AVMs embolized with isobutyl 2-cyanoacrylate (IBC-2) over a period of 3 years. All 16 AVMs were cortical in location; six involved the rolandic and speech areas, and four had a deep component. Ten AVMs were embolized through a transfemoral approach, an intraoperative approach was used for four cases, and a combined transfemoral/intraoperative approach was used in two cases. Complete obliteration of the AVM was obtained in one case. Partial obliteration and complete surgical resection was obtained in three cases. Obliteration of 70%-95% of the AVM was obtained in six cases and 45%-70% of the AVM was obliterated in six cases. IBC-2 embolization of the venous drainage was observed in three cases. After embolization, eight patients remained neurologically unchanged. Three patients had mild neurologic deficits that resolved completely within 48 hr; one had a deficit that cleared up 1 week later; and one had a deficit that disappeared within 6 months. In three patients a mild permanent neurologic deficit was evident 6 months after embolization.

Adult↗
PubMedDate not supplied

Progressive thrombosis of brain arteriovenous malformations after embolization with isobutyl 2-cyanoacrylate.

Embolization of brain arteriovenous malformations (AVMs) with isobutyl 2-cyanoacrylate (IBCA) is an alternative to surgical treatment when dealing with large AVMs with multiple arterial feeders. The deposition of IBCA in the nidus of the AVM may produce an active and progressive thrombosis that may lead to complete occlusion of the nidus and/or to progressive thrombosis of the draining veins. Four clinical examples of progressive thrombosis after IBCA embolization are demonstrated, including two cases in which late follow-up angiography showed complete obliteration of a partly embolized AVM.

Adult↗
PubMedDate not supplied

Clinical trial of Iohexol vs. Conray 60 for cerebral angiography.

Iohexol, a new nonionic contrast agent, and Conray 60 were compared in a double-blind clinical trial of 60 patients for safety, imaging effectiveness, and patient discomfort in cerebral angiography. There was no significant difference between the two agents in physiologic changes, film quality, or incidence of adverse effects in the 60 patients. One patient in the iohexol group suffered a cardiac arrest, which was clinically due to septic shock and was probably the result of inadvertent contamination of the iohexol used for test injections in this case. Bacterial growth can be supported in iohexol under certain circumstances, due to the lack of preservatives in this contrast material. The patients in the iohexol group experienced significantly less discomfort than the Conray 60 group. Iohexol is a safe, effective contrast agent when handled properly and causes less discomfort to patients than Conray 60.

Adult↗
PubMedDate not supplied

Preembolization superselective angiography: role in the treatment of brain arteriovenous malformations with isobutyl-2 cyanoacrylate.

Transfemoral and intraoperative embolization of arteriovenous malformations (AVMs) of the brain with isobutyl-2 cyanoacrylate may achieve complete and permanent occlusion of the AVMs. The preembolization superselective angiogram is an important source of information to decrease potential technical or clinical complications while seeking that goal. The information obtained from the angiogram of each individual feeder may be classified as anatomical, dynamic, and functional. This angiogram is performed either through a calibrated-leak balloon glued to a Silastic tubing, which is capable of negotiating cortical arterial curves, or through a short catheter directly placed into a feeder at surgery. In 64 patients, 175 preembolization superselective angiograms were obtained. Of those, 105 were obtained using the transfemoral technique, and 70 were obtained by direct catheterization after a craniotomy. Complications occurred in eight patients with only one permanent injury. Transient neurologic deficit occurred in five patients. One patient developed a permanent left monoplegia and one patient a subarachnoid hemorrhage without permanent neurologic deficit. In one patient, a delayed intracerebral hemorrhage produced a right hemiplegia and aphasia. The patient fully recovered in 6 months.

Bucrylate↗
PubMedDate not supplied

Effectiveness of contrast regimens in CT detection of vascular malformations of the brain.

Forty-three patients with cerebral vascular malformation were studied with precontrast, immediate contrast, and 1 hr delayed high dose contrast computed tomography (CT) scans. The precontrast scans were abnormal in 81% of patients. The delayed high dose scans demonstrated one angiographically occult, thrombosed arteriovenous malformation not seen on pre- or immediate contrast scans, four cases with additional zones of encapsulated hemorrhage or infarction not seen on pre- or immediate contrast CT, and two cases of venous angiomas seen on immediate contrast scans but not on delayed high dose scans. In 50% of patients, large vessels surrounding the malformation faded on the delayed dose scans which were less specific for vascular malformation than immediate contrast CT. We conclude that: (1) delayed high dose scans offer no significant advantage in patients with symptoms suggesting vascular malformation of the brain; and (2) while less specific than immediate contrast CT, these scans do not preclude detection of vascular malformations of the brain. Therefore, delayed high dose CT can be used in patients with suspected blood-brain barrier lesions without fear of missing vascular malformations.

Adolescent↗