Biomedical subjects
Publications and source records attributed to W Montanera.
The embolization of missiles to the intracranial circulation is a rare event. We describe here a case of a man shot by a shotgun, presenting with a posterior fossa stroke and occlusion of the superior cerebellar artery by a metallic pellet. To our knowledge, this is the third case of posterior fossa circulation pellet emboli.
Isolated dissecting aneurysms of the posterior cerebral artery are not as rare as previously reported. Affecting primarily a younger population, this condition can be recognized by angiographic patterns, the most common being a "pearl and string" morphology. We reviewed the literature and present a series of six cases, discussing management strategies.
OBJECT: To describe the clinical and angiographic results of endovascular occlusion of basilar bifurcation aneurysms with electrolytically detachable coils, and to identify factors which should be considered in deciding upon surgical or endovascular treatment. METHODS: We report our experience with 40 patients in whom occlusion of basilar bifurcation aneurysms with electrolytically detachable coils was attempted. All patients underwent superselective angiography and attempted embolization with Guglielmi detachable coils (GDCs). Angiographic and clinical results were prospectively recorded. Twenty-eight aneurysms presented with subarachnoid hemorrhage (SAH), 2 were symptomatic and 10 were incidental. RESULTS: Coils were not placed in 10 patients (25%) because of unfavorable anatomy. Complete aneurysm occlusion was achieved at the time of the initial procedure in 13 (32.5%), small neck remnants were present in 13 (32.5%), and in 4 (10.0%) there was obvious residual contrast filling of the aneurysm body. Of 23 patients successfully coiled after SAH, 20 were Grade 1 to 3 and 3 were grade 4 or 5 at the time of treatment. Eighteen (78%) made a good recovery. Procedural mortality was 2.5% and permanent morbidity was 7.5%. There were no permanent complications in patients with unruptured aneurysms. Complete aneurysm occlusion was possible in 10 (56%) of 18 aneurysms with small necks and 3 (14%) of 22 with large necks. Follow-up angiography in 25 of 28 surviving patients (mean, 12 months) demonstrated stability of all completely occluded aneurysms. Incompletely coiled aneurysms had variable results on follow-up angiograms: 15.4% improved, 69.2% worsened, and 15.4% were stable. No aneurysm bled after treatment during clinical follow-up averaging 22 months. CONCLUSIONS: Endovascular treatment of basilar bifurcation aneurysms appears to prevent early aneurysm rebleeding with acceptable rates of morbidity and mortality, but long-term follow-up is required.
BACKGROUND AND PURPOSE: Arteriovenous malformations (AVMs) of the spine or spinal cord can be characterized as spinal cord AVMs, spinal cord and dural arteriovenous fistulas, and AVMs occurring outside the dura but draining into the epidural veins. The purpose of this study was to review the clinical spectrum, imaging features, and results of treatment of paravertebral arteriovenous malformations (PVAVMs) with epidural drainage. METHODS: The clinical records and images of 10 patients with PVAVMs were analyzed retrospectively for clinical presentation, MR findings, angioarchitecture, pathophysiology, treatment efficacy, and clinical follow-up. RESULTS: Seven patients had myelopathy. The MR findings for three of these patients showed spinal cord hyperintensity on T2-weighted sequences and prominent perimedullary vessels. Angiography, performed in two of the three patients, showed evidence of reflux into the perimedullary veins from the PVAVMs. Each of these two patients underwent surgical clipping of the radicular vein leading to the perimedullary veins. In three of the seven patients, there were large epidural veins compressing the cord. Angiography performed in these patients showed large PVAVMs with multiple feeders, which were treated by a combination of transarterial and transvenous embolization. One of the seven patients had an associated spinal cord arteriovenous malformation. In three patients with incidental PVAVMs, cure was achieved by using a combination of coils and liquid adhesives by the endovascular route. CONCLUSION: The clinical presentation of PVAVMs is variable, and symptomatic lesions are the result of compression by epidural veins or of congestive myelopathy. A clear understanding of the anatomy and pathophysiology is necessary to plan treatment. Endovascular techniques are capable of curing the malformation, alleviating the symptoms, or both in a significant proportion of these lesions.
OBJECT: The goal of this study was to develop a classification system for aneurysms associated with arteriovenous malformations (AVMs) based on their anatomical and pathophysiological relationships and to determine the incidence and bleeding rates for these aneurysms as well as the effects of AVM treatment on their natural history. METHODS: Of 632 patients with AVMs, intranidal aneurysms were found in 35 (5.5%) and flow-related aneurysms in 71 (11.2%). Patients with intranidal aneurysms presented more frequently with hemorrhage (72% compared with 40%, p < 0.001) and had a 9.8% per year risk rate of bleeding during follow-up review. Twelve (17%) of the patients with flow-related aneurysms associated with an AVM presented with hemorrhage from an aneurysm, whereas 15 (21%) bled from their AVM. Seventeen patients underwent angiography after AVM treatment (mean 2.25 years). Of 23 proximal aneurysms, 18 (78.3%) were unchanged, four (17.4%) were smaller, and one (4.3%) had disappeared, whereas four (80%) of five distal aneurysms regressed completely and one was unchanged. Sixteen patients underwent angiography after partial AVM treatment (mean 3.8 years). In cases with less than a 50% reduction in the AVM, no aneurysms regressed, although two enlarged and bled. In cases with greater than a 50% reduction in the AVM, two of three distal aneurysms disappeared and five proximal aneurysms were unchanged. CONCLUSIONS: Arterial aneurysms associated with cerebral AVMs may be classified as intranidal, flow-related, or unrelated to the AVM nidus. Intranidal aneurysms have a high correlation with hemorrhagic clinical presentation and a risk of bleeding during the follow-up period that considerably exceeds that which would be expected in their absence. Patients with flow-related aneurysms in association with an AVM may present with hemorrhage from either lesion. Aneurysms that arise on distal feeding arteries near the nidus have a high probability of regressing with substantial or curative AVM therapy.
Over the past 25 years, the development of noninvasive imaging techniques has allowed exquisite display of the anatomic structures of the brain and spinal cord in normal and disease states. CT remains useful because of short imaging times, widespread availability, ease of access, sensitive detection of calcification and hemorrhage, and resolution of bony detail. MRI offers superior soft-tissue contrast, excellent visualization of vascular structures, fewer artifacts, and imaging in any plane. Cost and use of ionizing radiation are considerations in choosing the most appropriate procedure. In the future, CT and MRI applications that concentrate on functional and physiologic display of the CNS will add greatly to the clinical utility of these imaging tools.
The objective of this study was to evaluate the effect of preoperative steroid administration on the site and extent of upper airway edema after carotid endarterectomy. The design was a randomized, prospective, double-blind controlled trial. Thirty-eight patients undergoing elective carotid endarterectomy (17 patients were in the steroid-treated group and 21 in the control group) were administered either 16 mg of dexamethasone or saline placebo prior to surgery. Computed tomograms (CT) scans of the neck were performed on the patients preoperatively and 24 h postoperatively. Measurements were taken from the CT scans of the airway transverse and anterior-posterior diameters at the levels of the hyoid bone, arytenoid cartilage, and cricoid cartilage. No postoperative neck hematomas were seen on the CT scans. Although neck edema was observed postoperatively, the upper airway dimensions were not statistically significantly different between the steroid and the control groups. We conclude that steroid administration immediately preoperatively has no clinical effect in reducing edema formation in the upper airway postcarotid endarterectomy.
BACKGROUND: Intramedullary spinal cord abscess due to Listeria Monocytogenes is an uncommon condition usually affecting immunocompromised patients. METHOD: Case study. RESULTS: A 69-year-old man presented with 3 weeks history of subacute paralysis of both lower limbs and the left upper limb. Myelogram and CT scan showed a widened upper cervical cord. CSF revealed lymphocytosis, moderately elevated protein and depressed glucose. A gadolinium-enhanced MRI showed diffuse cervical cord edema with two ring-enhancing lesions at C2-C3. Blood and CSF cultures grew Listeria Monocytogenes. He received IV ampicillin and gentamycin; the latter was discontinued after 1 month due to nephrotoxicity. Serial MRI over the next 3 months showed significant reduction in the size of these abscesses. The patient made a modest improvement in the power of his lower limbs, however he remained bed-ridden. Aside from being a mild, diet-controlled diabetic, there was no evidence of immunosuppression. CONCLUSION: Listeria spinal cord abscess is a treatable disorder and should be considered in the differential diagnosis in patients with a subacute onset of spinal cord dysfunction.
Airway obstruction is a rare but serious postoperative complication of carotid endarterectomy. We prospectively studied airway dimensions between the hyoid bone and cricoid cartilage in patients undergoing carotid endarterectomy using preoperative and postoperative computed tomographic (CT) scans of the neck. CT scans showed soft tissue swelling in all 19 patients. Five patients with clinical evidence of airway obstruction and a hematoma present on CT scan were intubated postoperatively. The three-dimensional reconstruction of the neck from the CT scans showed a reduction in the volume of the airway in all patients. This reduction was greater in the intubated (62% +/- 9%) compared to the nonintubated (32% +/- 7%) patients (P < 0.01). The anterior-posterior and transverse diameters of the airway were reduced, while retropharyngeal edema was increased after carotid endarterectomy. This change was greater for the upper airway at the level of the hyoid compared to the arytenoids and cricoid, and was significantly greater in the intubated than the nonintubated patients. Tracheal deviation was greater in the intubated than in the nonintubated patients. These results demonstrate significant soft tissue edema of the neck after carotid endarterectomy that reduces airway volume and can result in airway obstruction.
Ninety-seven patients were referred to the Toronto Hospital (Western Division) between January 1984 and January 1992 for selective angiographic embolization (108 embolizations, including repeat procedures) to control intractable or recurrent severe epistaxis. Eighty-one patients (comprising 94 embolizations) were referred on an emergent basis because of failure of conventional conservative therapy, consisting of anterior and posterior packing. The remaining 16 patients (14 embolizations) were referred electively for recurrent epistaxis. A retrospective review of these cases was performed, with long-term telephone follow-up achieved in over 95% of cases. Embolization safely controlled active hemorrhage in 88% of the emergent cases. The success rate increased to 90% when two cases in which the source of epistaxis was found to be from the internal carotid artery were excluded (because these vessels could not be safely embolized). Of the patients whose epistaxis was initially controlled by embolization, 82% had no further nosebleeds (follow-up time ranged from 2 to 82 months; average, 26.8 months). More than half of the long-term failures were seen in patients with Osler-Weber-Rendu disease. Overall, the mortality rate was 0% and the long-term morbidity rate was 2% (one cerebral vascular accident and one case of skin slough in the territory of the superficial temporal artery.
PURPOSE: To present the MR findings of intracranial dural arteriovenous malformations with cortical venous drainage, emphasizing the parenchymal changes. METHODS: Conventional MR and x-ray angiograms in 13 patients with dural arteriovenous malformations and cortical venous reflux were reviewed. The site of the shunt, location of the venous reflux, and presence of venous stenosis were assessed on the angiograms. Parenchymal changes, dilated vessels, and venous occlusive disease were assessed on MR. RESULTS: On MR, 10 of the 13 patients (77%) had dilated pial vessels. Two patients had hydrocephalus. Two patients presented with parenchymal bleeds, one with a subdural component, both remote from the nidus. Two patients presented with subarachnoid hemorrhage. One patient had a parenchymal bleed 9 months after presentation. Venous occlusion was evident on MR in 2 patients. Diffuse white matter edema in the cerebellar or cerebral hemispheres was present on MR in 4 patients and correlated with neurologic deficits. In 2 of these 4 patients, gadolinium enhancement was seen in the periphery of the involved hemisphere. CONCLUSIONS: On MR a surplus of pial vessels suggests a dural arteriovenous malformation with cortical venous drainage. The MR finding of white matter edema deep in the cerebral or cerebellar hemispheres is direct evidence of a venous congestion.
We reviewed the clinical and radiological features of ten patients with small arteriovenous malformations that caused intracerebral hematomas. In six patients, angiography showed a small nidus (less than 1 cm in diameter) with a shunt at the site of the hematoma, and in four only an early-filling vein was evident. Six patients had only delayed angiography (4 weeks or more after the ictus). In three, angiography within 2 days of the ictus failed to reveal the cause of the bleed, but repeat angiography showed an early-filling vein in two, and a nidus with shunting in one. In only one patient did early angiography reveal the malformation. MRI was obtained in eight patients, and in two prominent vessels were evident in the wall of the hematoma cavity. In investigation of an unexplained intracerebral hematoma, MRI may be useful to exclude a neoplasm or cavernoma, although the latter may be not be evident in the presence of a recent hematoma. We suggest early MRI and angiography for investigation of an unexplained, nonhypertensive intracerebral bleed, with follow-up MRI and delayed angiography if the initial studies fail to reveal the cause.
The artery of Adamkiewicz infrequently originates from the same radicular vessel that also supplies a dural arteriovenous fistula. This variant is not adequately emphasized in the neuroradiological literature. Awareness of this entity is essential to prevent catastrophic complications during embolization. We report such a case, and our experience with attempted embolization. We are unaware of any previously reported instance of such an attempt being made.
An attempt has been made to simplify and to provide an understanding of some of the new modalities for evaluation of head and neck pathology. Both CT and MRI are complementary to each other: MRI being superior to CT in evaluating soft tissue, and CT being superior to MRI in assessing fine bony details and in identifying microcalcifications. MRI is the modality of choice for tumor evaluation because it has several advantages over CT in assessing the location, spread, and staging of the disease. HRCT scanning remains the procedure of choice in the evaluation of middle ear and base of the skull, and in the evaluation of benign sinonasal disease. CPA and IAC lesions are best evaluated by MRI. Three-dimensional surface reformations of axial CT scans enable the surgeon to plan the operative approach needed to reduce facial fractures and to repair cranial deformities.
The authors report the results of treatment in 49 consecutive patients with brain arteriovenous malformations (AVM's) who underwent therapeutic embolization with liquid adhesive agents between 1984 and 1988 at the Toronto Western Hospital. Thirty-three patients had no other treatment and were followed up with angiography at 2 years and clinically from 2 to 6 years. Of the other 16 patients, 10 had adjunctive radiosurgery and six underwent surgical resection following embolization. Seven (14%) of the 49 patients had a morphological cure effected by embolization as evidenced on their 2-year follow-up angiograms: these have remained clinically stable. Twelve patients developed neurological deficits after embolization; eight (16% of the series) were transient and four (8%) were permanent. Two patients (4%) had a delayed hemorrhage after incomplete obliteration of their malformations. Endovascular treatment resulted in clinical improvement in 15 (33%) of the other 46 patients. None of the patients who initially presented with hemorrhage had a rebleed following embolization. It is concluded that endovascular treatment with liquid embolic material can be an integral part of the multidisciplinary treatment protocol for patients with brain AVM's.
The authors reviewed four patients with dural arteriovenous malformations in the upper spinal axis. Two were at the foramen magnum and two were lower cervical. The patients presented with subarachnoid hemorrhage, a slowly progressive cervical myelopathy, a rapidly progressive thoracic myelopathy, and tinnitus with a sixth nerve palsy. This report emphasizes the importance of studying both the intracranial dural vessels as well as the supply to the cervical spine in searching for a spinal arteriovenous malformation. Subarachnoid hemorrhage with negative cerebral angiography requires spinal angiography if there are any signs or symptoms suggesting cord or nerve root dysfunction. Embolization by an endovascular approach resulted in an angiographic cure in two patients. A combination of embolization and surgery resulted in obliteration of the arteriovenous malformation in one patient. Embolization achieved a clinical cure in one patient, and clinical improvement in two patients.
The occurrence of intracranial aneurysms in the pediatric population is a rare phenomenon. An unusual case of aneurysmal dilatation of both petrous and cavernous carotid arteries and the vertebral-basilar junction in a child is presented. The underlying etiology, natural history, and possible modes of management are reviewed and discussed.
We describe transfemoral cerebral angiography of New Zealand white rabbits used to study the cerebral circulation, electroencephalogram, and histologic correlates of selective internal carotid infusion during embolic stroke.