A photothrombotic model of small early ischemic infarcts in the rat brain with histologic and MRI correlation.

Over the last two decades several studies have suggested the role of photothrombotic occlusion of cerebral microvessels using rose bengal, resulting in small strokes in rodents that resemble those in humans. This paper describes such a photothrombotic method of acute small stroke induction in rats with histopathologic and in vivo magnetic resonance imaging (MRI) observations from 3 to 6 h after irradiation, which is homologous to a human autopsy specimen. Utilizing 30 min of irradiation with minimal beam intensity (0.1 W/cm(2)) cold white light in conjunction with 20 mg of intravenous (iv) rose bengal as a rapid infusion, small infarcts were induced photochemically in the frontal lobes of six rats. The infarcts showed a consistent pattern on histologic and in vivo MR sections when examined within 7 h or less of irradiation. Both MRI and histologic sections were comprised of (a) a superior zone of infarcted neurons, (b) a middle curvilinear transition zone of edema on MRI and histologically vacuolated neuropil, and (c) an inferior zone of normal neurons. Shorter duration water-sensitive (T2)- and postgadolinium longer duration (T1)-weighted signal decay images both showed a curvilinear hyperintense transition zone of edema. The mean infarct and transition zone areas measured from the histologic sections were comparable to those measured on the MRI. The infarct model described above allows in vivo observations using MRI with the potential for use in testing putative neuroprotective agents. As demonstrated by a comparison with the histologic features of such infarcts in surgical and autopsy brain specimens, the model is relevant to acute human ischemic infarcts.

CT analysis of a complicated nasopalatine duct cyst.

A study was conducted to evaluate CT imaging in differentiating nonodontogenic nasopalatine duct cysts from odontogenic radicular cysts. The patient's palatine cystic lesion was analyzed by CT and excised with postoperative microscopic identification. CT findings of a nasopalatine cyst are midline location, smooth expansion with sclerotic margins and displacement of teeth apices. Radicular cysts differ in that the teeth apices are within the cyst rather than being displaced. We concluded that differentiation is clearly demonstrated by CT images.

Clinicopathological correlations in syringomyelia using axial magnetic resonance imaging.

Axial magnetic resonance (MR) images of non-neoplastic spinal cord cavities were reviewed in 115 patients with otherwise complete neurological and neuroradiological findings. The variations in axial morphology revealed three distinct cavitary patterns. These patterns were as follows: 1) symmetrically enlarged central cavities (28 patients); 2) central cavities that expanded paracentrally in one or more focal areas (36 patients); and 3) eccentric cavities that were off-center, frequently irregular, and sometimes associated with myelomalacia (51 patients). The radiological patterns of spinal cord cavitation correlated well with recently reported histopathological findings that distinguish simple dilations of the central canal, dilations of the central canal that dissect paracentrally, and primary cavitations of the spinal cord parenchyma (extracanalicular syringes). Like histologically confirmed central canal syringes, MR-defined central cavities were associated with pathogenic factors that affect the dynamics of the cerebrospinal fluid, including hindbrain malformations, hydrocephalus, and extramedullary obstructive lesions. Eccentric cavities resembled extracanalicular syringes and occurred typically with disorders that damage spinal cord tissue (e.g., trauma, infarction, meningitis/arachnoiditis, spondylosis/disc herniation, radiation necrosis, and transverse myelitis). Analysis of clinical findings at the time of MR imaging established the following correlations. 1) Symmetrically enlarged central cavities were asymptomatic or produced nonspecific neurological signs. 2) Central cavities that expanded paracentrally were associated with segmental signs referable to the paracentral component. 3) Eccentric cavities produced various combinations of long tract and segmental signs that could usually be related to the level, side, and specific quadrant of spinal cord cavitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Platinum coil treatment of complex aneurysms of the vertebrobasilar circulation.

Two patients with complex aneurysms of the vertebrobasilar system were treated using platinum coils. During these sessions, 22 coils were placed in a basilar tip aneurysm in a 48-year-old woman. Almost total occlusion of the lumen was achieved, excepted in the area from which the right posterior cerebral artery arose. A large fusiform vertebral artery aneurysm in a 6-year-old boy was treated using 16 coils, which partially occluded the lumen at initial embolization. Follow-up angiography 2 weeks later revealed almost complete occlusion of the lumen with preservation of the vertebral artery. Our experience indicates that coil embolization of complex intracranial aneurysms is an acceptable treatment alternative to surgery or to a detachable balloon.

Symptomatic vascular malformations: ethanol embolotherapy.

Absolute ethanol was used to perform nine transcatheter embolizations and 21 direct percutaneous puncture embolizations in eight patients with unresectable vascular malformations. Six patients had arteriovenous malformations and two patients had hemangiomas. Four of these patients had undergone unsuccessful surgery, and the other four were not considered candidates for operation. All large complex symptomatic vascular malformations (SVMs) required multiple embolizations that were staged procedures. Ethanol embolotherapy, performed according to strict techniques, has proved efficacious in the management of SVMs.

Treatment of a central arteriovenous malformation of the mandible with cyanoacrylate: a 4-year follow-up.

Large arteriovenous malformations of the jaws are relatively rare, potentially life-threatening lesions. When the lesion is not suspected, extraction of teeth can be fatal. The occurrence and treatment of arteriovenous vascular communications in the head and neck region have traditionally presented most perplexing problems. Traditional treatment has usually involved the obtaining of proximal and distal vascular control and surgical removal of the lesions, when feasible. This article presents a case that is of particular interest because it illustrates the successful use of cyanoacrylate as the only treatment for a large arteriovenous malformation of the left side of the mandible. A 4-year follow-up shows no evidence of the lesion and demonstrates complete regeneration of bone in the same area.

Magnetic resonance imaging of the lumbar spine. A comparison with computed tomography and myelography.

Two hundred and fifty patients were referred for magnetic resonance imaging (MRI) of the lumbar spine. Computed tomography (CT) and MRI were performed in 50 patients and MRI, CT and myelography in 20 patients. Twenty patients had surgical confirmation of the imaging studies. MRI was best for demonstrating degenerated discs. MRI was better than CT for demonstrating disc bulge without herniation, and MRI was slightly better for herniated disc demonstration than CT. Myelography did not demonstrate degenerated discs.

Morphological studies of human arteriovenous malformations. Effects of isobutyl 2-cyanoacrylate embolization.

Ten patients with symptomatic arteriovenous malformations (AVM's) underwent embolization with isobutyl 2-cyanoacrylate (Bucrylate) delivered via a mini-balloon catheter according to the protocol of George and Pevsner. These patients underwent surgical removal of their embolized AVM, and surgical specimens were evaluated by light and scanning electron microscopy. Ten other patients with AVM's underwent surgical resection without prior embolization, and these surgical specimens were evaluated in a similar manner. Results from this study indicate that Bucrylate incites an inflammatory response characterized by foreign-body giant cells. This reaction was present as early as 3 weeks after embolization and persisted in specimens resected almost 1 year after the last embolization. No such reaction was observed in unembolized AVM's. Both light and scanning electron microscopy demonstrated a lattice structure of the Bucrylate embolus within the AVM vessels. These studies also demonstrated micro-channels within the Bucrylate embolus and the presence of what appears to be normal red blood cells within the latticework of the embolus. Vascular endothelium not in direct contact with the Bucrylate embolus retains a normal morphology as revealed by scanning electron microscopy.

Ethyl alcohol: experimental agent for interventional therapy of neurovascular lesions.

Perfusion of absolute ethyl alcohol into the middle cerebral artery of six rhesus monkeys was performed using the Pevsner miniballoon catheter system. The animals were sacrificed by thoracotomy and intracardiac perfusion of a mixed aldehyde solution for fixation. Preliminary angiography and electron microscopy suggest absolute ethyl alcohol is a good neurovascular occlusive agent, and a possible replacement for isobutyl 2-cyanoacrylate in the treatment of angiomas and tumors.

Interventional radiology polymer update: acrylic.

An overview of intravascular interventional embolic materials is presented. The physicochemical and biological properties of the monomer isobutyl 2-cyanoacrylate are discussed with specific details regarding therapeutic applications.

Therapeutic embolization with a microballoon catheter system.

Clinical experience with a new embolization and perfusion microballoon catheter system is presented in 34 patients with angiomas, arteriovenous fistulas, and cerebral hemorrhages. The system uses two separate balloon tips, one for detachment as an embolus and one for perfusion of elastomer. The criteria for catheter and perfusate selection are described. One permanent complication, two temporary complications, and one death occurred in this series. The technique represents a primary mode of therapy for treatment of certain vascular lesions, especially in nonsurgical candidates by virtue of their lesion or clinical state. Abdominal and extremity applications in 15 additional patients are also described. No complications occurred in these patients.

Multiple axis image reconstruction from axial transverse data.

The technique for alternate axis reconstruction from axial transverse computed tomography data is presented. The utility of the method as an adjunct to diagnosis, radiotherapy treatment planning, and tumor biopsy is discussed. The relative radiation dose and resolution characteristics between this and other methods are compared.

Vascular injury and penetrating facial trauma.

Three patients with gunshot wounds to facial and vascular structures were described. They demonstrate the importance of angiography in the acute care phases of treatment. In one case, angiography lead to eventual surgical management of an arteriovenous fistula. The other two cases described arterial injury that required careful surgical follow-up to detect delayed complications.

Computed tomography in a primate stroke model using selective balloon catheter arterial occlusion.

Ten heparinized nonhuman primates (rhesus monkeys and Papio maryumaya baboons) were subjected to temporary occlusion of an insular branch of the middle cerebral artery with a balloon catheter. An infarct was created. The lesions were monitored in vivo by computed tomography performed at intervals for 1 year. Animals were sacrificed and the lesions examined histologically. The technique obviates the disadvantages of surgical reaction, intravascular thrombosis, and gross cerebral edema observed in prior animal stroke models.

Failure of computer assisted tomography to detect experimental acute obstruction of major pulmonary arteries.

Large perfusion defects were produced by total balloon occlusion of major branch pulmonary arteries in two baboons and one dog. The position and total occlusion were confirmed by pulmonary angiograms. Computer assisted tomography (CAT) failed to demonstrate any difference in the nonperfused segment of lung either before or after intravenous contrast injection.

Micro-balloon catheter for superselective angiography and therapeutic occlusion.

A miniature (0.5 mm) flow-directed balloon catheter with two different silastic balloon tips has been developed. One tip is used for perfusion; the other can be inflated and released to produce vascular occlusion. Examples of the developmental work in dogs and clinical use in patients are presented.

Subependymal and intraventricular hemorrhage in neonates. Early diagnosis by computed tomography.

Computed tomography was used to evaluate subependymal and intraventricular hemorrhage in 11 formalin-fixed brains obtained at autopsy from newborn infants from a population with a known high incidence of cerebral hemorrhage. After scanning, the brains were step-sectioned at levels corresponding to those of the scans. Subependymal and/or intraventricular hemorrhage was demonstrated in 6 of the 11 brains. There was a very close correlation between the scan images and the gross pathological findings in the affected brains. The authors conclude that computed tomography is an accurate method for the diagnosis of neonatal cerebral hemorrhage.