Biomedical subjects
Publications and source records attributed to A Berenstein.
A simple and reliable technique is described for investigating the precise location of an arteriovenous fistulous communication and its hemodynamics by temporary and complete vessel occlusion with a double-lumen balloon catheter.
The functional anatomy of the facial artery consists of a group of constant arterial pedicles nourishing a specific territory and supplied by a variable facial trunk. There is a hemodynamic balance with other variable connecting trunks such as the transverse facial and internal maxillary arteries. Every type of variant, irrespective of its origin, may be understood based on the constant relationships and anastomoses involved. Knowledge of this functional anatomical system is crucial to an understanding of the blood supply to the face.
The preoperative contrast enhanced CT and radionuclide brain scans of 60 patients with surgically verified supratentorial astrocytomas were evaluated and compared. Results indicated that the mechanisms of contrast enhancement and radionuclide uptake are identical in the detection of supratentorial gliomas. These diagnostic methods apparently mirror the integrity of the blood-brain barrier and therefore can be useful in assessing the degree of malignancy of supratentorial gliomas. However, lesions with an intact blood-brain barrier will be missed with radionuclide imaging. These parenchymal abnormalities and/or the associated mass effect will be detected with contrast enhanced computed tomography. These findings firmly establish contrast enhanced computed tomography. These findings firmly establish contrast enhanced CT as the primary investigate tool in the suspected brain tumor.
The preoperative contrast-enhanced CT scan and the radionuclide brain scan of 70 patients with surgically verified supratentorial astrocytomas were evaluated and compared. The results indicate parallel mechanisms of action of contrast enhancement and radionuclide uptake. These diagnostic modalities apparently mirror the integrity of the blood-brain barrier (BBB) and therefore are useful in assessing the degree of malignancy of supratentorial gliomas. However, lesions with an intact BBB will be missed with RN imaging. These lesions and/or the associated mass effect will be detected with contrast-enhanced computed tomography. Our findings firmly establish contrast-enhanced CT as the primary investigate tool in the suspected brain tumor.
Therapeutic vascular occlusion has been developed to a practicable point by now. The materials used and methods practiced in the Department of Radiology of the New York University School of Medicine are presented in detail.
Two unique cases are presented of infants with signs of vein of Galen malformations, whose unsuspected associated sinus venosus atrial septal defects were detected during routine echocardiography. A conservative approach to cardiac treatment is advocated.
The topic of interventional radiology of the extracranial head and neck is reviewed. Knowledge of functional vascular anatomy and recognition of the "dangerous anastomoses" between the external carotid artery and the intracranial circulation are stressed. Technical aspects of embolization are surveyed. The authors' approach to some of the more common lesions such as paragangliomas, congenital vascular lesions, epistaxis, juvenile angiofibromas, and arteriovenous fistulas are described. Illustrative cases are presented. Proper training and experience are needed in order to safely and effectively perform embolization procedures of the head and neck.
BACKGROUND AND PURPOSE: Neuroendovascular surgery/interventional neuroradiology is a relatively new subspecialty that has been evolving since the mid-1970s. During the past 2 decades, significant advances have been made in this field of minimally invasive therapy for the treatment of intracranial cerebral aneurysms; acute stroke therapy intervention; cerebral arteriovenous malformations; carotid cavernous sinus fistulas; head, neck, and spinal cord vascular lesions; and other complex cerebrovascular diseases. Advanced postresidency fellowship programs have now been established in North America, Europe, and Japan, specifically for training in this new subspecialty. METHODS: From 1986 to the present, an ad hoc committee of senior executive committee members from the American Society of Interventional and Therapeutic Neuroradiology, the Joint Section of Cerebrovascular Neurosurgery, and the American Society of Neuroradiology met to establish, by consensus, general guidelines for training physicians in this field. RESULTS: In April 1999, the Executive Committee of the Joint Section of Cerebrovascular Neurosurgery voted unanimously to endorse these training standard guidelines. In May 1999, the Executive Committee of the American Society of Interventional and Therapeutic Neuroradiology and the American Society of Neuroradiology also unanimously voted to endorse these guidelines. In June 1999, the Executive Council of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons unanimously voted to endorse these guidelines. CONCLUSION: The following guidelines for residency/fellowship education have now been endorsed by the parent organization of both the interventional and diagnostic neuroradiology community, as well as both senior organizations representing neurosurgery in North America. These guidelines for training should be used as a reference and guide to any institution establishing a training program in neuroendovascular surgery/interventional neuroradiology.
Two cases of aneurysmal malformations of the vein of Galen with later spontaneous thrombosis are reported. Angiograms before thrombosis in both cases showed mural type aneurysmal malformations of the vein of Galen with slow arteriovenous shunts and associated stagnation of contrast in the venous sac secondary to severe outflow restriction. Based on these angiographic findings, the patients were managed conservatively and the arteriovenous malformations of the vein of Galen thrombosed with good clinical outcomes. Twenty cases of spontaneous thrombosis previously reported in the literature are reviewed.
To test the value of currently proposed angiographic categorizations of vein of Galen malformations and a hypothesis regarding the causes of vein of Galen malformations and of accompanying hydrocephalus, as well as to assess the relative utility of MR imaging and CT in clinical evaluation, we reviewed the clinical and radiologic records of 34 patients with vein of Galen malformations. Patients were divided into two groups on the basis of the angiographic demonstration of either an arteriovenous malformation nidus or a direct arteriovenous fistula to the wall of the vein of Galen or one of its tributaries. Patients with such a nidus (n = 17) could be distinguished from those with arteriovenous fistulas alone (n = 17) on the basis of age at presentation (p less than .01) and presenting symptoms. Venous constraints, thought to be etiologically important, were identified in 31 of 34 patients. The presence or absence of hydrocephalus was explainable by mass effect in only 24 of 32 patients. In seven of 32 cases, no obvious mass effect was seen in the presence of hydrocephalus, but arteriographic evidence of venous hypertension was present in all patients with hydrocephalus. MR provided improved depiction of both arterial and venous anatomy as compared with CT. Parenchymal abnormalities were uncommon. No patients had subarachnoid hemorrhages. We conclude that MR is superior to CT in the clinical evaluation of vein of Galen malformations, that the angiographic finding of a nidus separates patients with vein of Galen malformations into clinical and therapeutically relevant groups, and that simple mass effect on the aqueduct is not an adequate explanation for all cases of hydrocephalus in patients with this disease.
Nineteen arteriovenous fistulas of the external carotid branches in 17 patients were treated by a variety of percutaneous transvascular techniques. There were nine females and eight males; 11 fistulas were traumatic in origin, five were "spontaneous," and three were thought to be congenital. The most frequent presenting symptoms were a bruit and thrill, followed by pulsatile tinnitus, pulsatile mass, headaches, and ocular problems. The symptoms were related to fistula site and venous drainage. The middle meningeal artery was involved most often, followed by the superficial temporal, occipital, internal maxillary, and ascending pharyngeal arteries. All patients except one were successfully cured, including one recurrence. There were no complications, and the hospital stay averaged 3 days.
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The authors describe the functional anatomy of the facial vascular system, using the anastomoses between the facial, maxillary, transverse facial, lingual, and ophthalmic systems to selectively identify the blood flow to a specific territory for embolization and posttreatment evaluation of hemangiomas. In three patients the specific vascular patterns are described and the usefulness of understanding the regional functional anatomy is illustrated for successful embolotherapy of these malformations.
Vascular occlusion is described using microemboli of a predetermined size for the treatment of neoplastic conditions with a "capillary barrier." Particulated microemboli of either 40--60 micron Gelfoam powder or 200--1,000 micron polyvinyl alcohol foam (PVA) are best. Fluid embolic agents such as silicone fluid are used in lesions without a capillary barrier. The radiographic, pathologic, and clinical results in three patients are described in detail. Microembolization is useful in the treatment of neoplastic conditions for it produces tumor necrosis in addition to hemostasis.
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