Silent thromboembolic events associated with the treatment of unruptured cerebral aneurysms by use of Guglielmi detachable coils: prospective study applying diffusion-weighted imaging

BACKGROUND AND PURPOSE

Aneurysm embolization using Guglielmi detachable coils (GDC) is gaining increasing acceptance as a viable alternative to surgery in the treatment of cerebral aneurysms. Although recent reports describe a significant rate of symptomatic thromboembolic complications with GDC use, many of the neurologic deficits are transient. We sought to determine the incidence of silent thromboembolic events with the use of diffusion-weighted imaging and to correlate radiologic findings with the results of neurologic examinations.

METHODS

Diffusion-weighted MR imaging was performed within 48 hours in 14 consecutive elective GDC aneurysm treatments. Embolizations were performed under systemic heparinization; all flush solutions were heparinized, and both guiding catheters and microcatheters were placed for continuous heparinized infusions. Neurologic examination, including the National Institutes of Health Stroke Scale determination, was performed by a stroke neurologist before the coiling procedures were performed, immediately after the procedures were performed, and before discharge. MR imaging examinations were reviewed by a stroke neurologist and an interventional neuroradiologist, with determination and characterization of diffusion-weighted imaging abnormalities.

RESULTS

Small areas of restricted diffusion, presumed to represent procedure-related embolic infarctions, were noted on the images of eight of 14 patients. All except one of the areas were located ipsilateral to the side of the catheterization. Six patients had evidence of multiple infarcts. Most lesions were small (<2 mm); one patient with coil stretch and herniation into the parent vessel had numerous infarcts with a dominant posterior frontal infarct. Pre- and posttreatment National Institutes of Health Stroke Scale scores were unchanged for 13 of 14 patients. Overall, the rate of asymptomatic emboli was 61% (eight of 13 treatments) in uncomplicated treatments. Strokes occurred independently of the number of coils used; the mean number of coils used for patients with strokes was 7.6 (range, two to 13) and for patients without evidence of infarcts was 10.2 (range, one to 30). This was not a significant difference (P > .5).

CONCLUSION

Silent thromboembolic events related to the use of the GDC system are a common occurrence, despite meticulous technique and systemic anticoagulation. Although clinical sequelae are rare, the high rate of occurrence suggests that alterations in the technique, such as the addition of antiplatelet agents, should be considered.

Results after surgical and endovascular treatment of paraclinoid aneurysms by a combined neurovascular team

OBJECTIVE

Advances in surgical and endovascular techniques have improved treatment for paraclinoid aneurysms. A combined surgical and endovascular team can formulate individualized treatment strategies for patients with paraclinoid aneurysms. Patients who are considered to be at high surgical risk can be treated endovascularly to minimize morbidity. We reviewed the clinical and radiographic outcomes of 238 paraclinoid aneurysms treated by our combined surgical and endovascular unit.

METHODS

From 1991 to 1999, the neurovascular team treated 238 paraclinoid aneurysms in 216 patients at the Massachusetts General Hospital. The modality of treatment for each aneurysm was chosen based on anatomic and clinical risk factors, with endovascular treatment offered to patients considered to have higher surgical risks. One hundred eighty aneurysms were treated by direct surgery, 57 were treated by endovascular occlusion, and one was treated by surgical extracranial-intracranial bypass and endovascular internal carotid artery balloon occlusion. Locations were transitional, 12 (5%); carotid cave, 11 (5%); ophthalmic, 131 (55%); posterior carotid wall, 38 (16%); and superior hypophyseal 46 (19%). Lesions contained completely within the cavernous sinus were excluded from this analysis.

RESULTS

Using the Glasgow Outcome Scale (GOS), overall clinical outcomes were excellent or good (GOS 5 or 4), 86%; fair (GOS 3), 7%; poor (GOS 2), 4%; and death (GOS 1), 3%. Among the surgically treated patients, 90% experienced excellent or good outcomes (GOS 5 or 4), 6% had fair outcomes (GOS 3), 2% had poor outcomes (GOS 2), and 3% died (GOS 1). Among the endovascularly treated patients, 74% had excellent or good outcomes (GOS 5 or 4), 12% had fair outcomes (GOS 3), 10% had poor outcomes (GOS 2), and 4% died (GOS 1). The overall major and minor complication rate from surgery was 29%, with a 6% surgery-related permanent morbidity rate and a mortality rate of 0%. The overall major and minor complication rate from endovascular treatment was 21%, with a 3% endovascular-related permanent morbidity rate and a 2% mortality rate. Visual outcomes for patients who presented with visual symptoms were as follows: improved, 69%; no change, 25%; worsened, 6%; and new visual deficits, 3%. In general, angiographic efficacy was lower in the endovascular treatment group.

CONCLUSION

A combined team approach of direct surgery and endovascular coiling can lead to good outcomes in the treatment for paraclinoid aneurysms, including high-risk lesions that might not have been treated in previous surgical series.

Choroid plexus changes after temporal lobectomy

BACKGROUND AND PURPOSE

Postoperative contrast-enhanced MR imaging of the brain is routinely used when evaluating for residual or recurrent brain tumor. It is imperative to be aware of morphologic changes and imaging features that typically occur in response to surgical manipulation at the postoperative site to avoid misinterpretation of imaging findings. Our purpose was to determine normal postoperative changes and alterations in the choroid plexus among patients who had undergone temporal lobectomy in order to distinguish this appearance from pathologic changes that may be seen in the presence of infection or recurrent tumors.

METHODS

We reviewed 159 MR scans from 95 patients with hippocampal sclerosis or gliosis who underwent temporal lobectomy for treatment of intractable epilepsy. Choroid plexus location and size were assessed on contrast-enhanced T1-weighted images.

RESULTS

After temporal lobectomy, the choroid plexus enlarged and sagged into the resection site. Increase in the size of the choroid plexus occurred in 58% of cases overall. The degree of enhancement also increased after surgery, sometimes resulting in a nodular pattern of enhancement. The changes were most marked during the 1st week after temporal lobectomy, and showed an enlarged, markedly enhancing choroid plexus on 86% of the scans.

CONCLUSION

Postoperative changes of the choroid plexus after temporal lobectomy include sagging into the resection site, an increased size, and an increased degree of enhancement. Normal postoperative morphologic characteristics may mimic neoplastic enhancement pattern. Familiarity with this appearance is important to avoid a pitfall in diagnosis of recurrent postoperative temporal lobe neoplasms.

Multimodality treatment of nongalenic arteriovenous malformations in pediatric patients

OBJECTIVE

Previously reported series of arteriovenous malformations (AVMs) in pediatric patients have primarily used a single-modality treatment approach of either surgery, radiosurgery, or embolization, with significant treatment-related morbidity and mortality. At our institution, we have used a combined multidisciplinary team approach of all three treatment modalities, alone or in combination, to minimize complications and to maximize efficacy in the management of these lesions.

METHODS

We retrospectively reviewed 40 consecutive pediatric patients with AVMs seen at our institution from 1991 to 1999. A multidisciplinary team planned the treatment for each AVM. The treatment modality consisted of the following approaches: surgery alone in 14 patients, a combination of endovascular embolization and surgery in 6 patients, radiosurgery alone in 11 patients, a combination of endovascular embolization and radiosurgery in 2 patients, and a combination of radiosurgery and surgery in 2 patients. Four patients are receiving ongoing multistaged treatment for reduction of the nidus size for eventual surgical resection or radiosurgical obliteration of large, complex lesions. In one patient, no treatment was recommended.

RESULTS

The clinical outcomes for the overall series were 95.0% excellent or good (Glasgow Outcome Scale score 5 or 4), 2.5% fair (Glasgow Outcome Scale score 3), and 2.5% dead. Radiographic efficacy in the patients who have completed treatment was 92.9% complete obliteration of their AVMs and 7.1% incomplete obliteration. Of the 10 patients who had seizures, 9 are seizure-free.

CONCLUSION

A combined multimodality approach of surgery, radiosurgery, and embolization in managing AVMs in pediatric patients can improve outcomes and minimize morbidity and mortality.

Parenchymal perianeurysmal cystic changes in the brain: report of five cases

PURPOSE

To describe parenchymal perianeurysmal cystic changes in the brain.

MATERIALS AND METHODS

Among 247 patients with cerebral aneurysms described in the medical or radiologic records in three institutions, five had perianeurysmal cystic changes. These were evaluated with computed tomography or magnetic resonance (MR) imaging and were categorized according to size, appearance, and the presence of hemosiderin deposit. Confirmation at stereotactic needle biopsy was available in one case.

RESULTS

Perianeurysmal cysts comprised multiple clustered cysts in three cases and a unilocular cyst in two, and diameters were 1.5-3.5 cm. Hemosiderin was depicted at MR imaging in one unilocular cyst. Associated aneurysms had diameters of 0.7-4.0 cm, and prominent aneurysmal thrombosis and calcifications were seen in two cases. Findings at stereotactic needle biopsy were of mild reactive gliosis. At long-term follow-up in two patients, the cystic regions were stable.

CONCLUSION

Parenchymal perianeurysmal cysts are rare and may display various morphologic characteristics from unilocular to multilocular. Since there may or may not be evidence of previous hemorrhage, other mechanisms such as abnormal angiogenesis factors may play a role.

Recurrent carotid blowout syndrome: diagnostic and therapeutic challenges in a newly recognized subgroup of patients

BACKGROUND AND PURPOSE

To our knowledge, recurrent carotid blowout syndrome (rCBS) has not been well described. Our purpose was to review our institution's recent experience with patients who presented with multiple episodes of carotid blowout syndrome (CBS), and who were referred for emergent diagnostic angiography and endovascular therapy.

METHODS

We retrospectively reviewed the last 46 consecutive patients who had a clinical diagnosis of CBS. All patients were examined and treated prospectively according to a standardized protocol. Most patients (43 of 46) had undergone extensive primary and salvage radical surgery with intraoperative brachytherapy or external beam radiation or both. The remaining three patients had either traumatic or iatrogenic CBS.

RESULTS

Twelve patients (26%) in our series had more than one episode of CBS in which a total of 32 (20 recurrent) events were observed (average 2.7, range 2-4). Intervals of rCBS ranged from 1 day to 6 years. Thirteen (65%) of 20 recurrent events were attributed to progressive disease (PD), and seven (35%) of 20 to treatment failures (TFs). In the PD group, seven (54%) of 13 had recurrent ipsilateral disease, and six (46%) of 13 had recurrent contralateral disease. Etiologies of rCBS were as follows: seven exposed carotids; seven carotid pseudoaneurysms; eight small-branch pseudoaneurysms; five tumor hemorrhages; three hyperemic/ulcerated wounds; and one aortic arch rupture. Twenty-seven of 32 events were treated with endovascular therapy, which included the following: nine carotid occlusions; 11 small-branch embolizations; three transarterial tumor embolizations; one carotid stent; and two direct-puncture embolizations. Four of six TFs were retreated successfully with endovascular therapy; the remaining two TFs were managed successfully by surgery. In the PD group, hemorrhagic complications of rCBS were managed successfully in all but one patient, who died. No permanent neurologic or ophthalmologic complications occurred.

CONCLUSION

Recurrent CBS is a frequently encountered problem in which most cases are caused by PD resulting from both multifocal iatrogenic arteriopathy and occasional wound complications that are characteristic of aggressively managed head and neck surgical patients. Initial TFs are encountered often as well. Despite the diagnostic and therapeutic challenges of rCBS, most cases can be retreated effectively.

Effect of internal maxillary arterial occlusion on nasal blood flow in swine

OBJECTIVES

The precise effects of therapeutic occlusion of the internal maxillary artery (IMA) on distal nasal mucosal perfusion are unknown. A better understanding of these effects has important implications regarding the rationale and expected efficacy of certain therapeutic interventions for epistaxis management. The authors developed an animal model to assess these issues.

STUDY DESIGN

The effects of "proximal" and progressively more "distal" occlusions of the IMA on nasal mucosal blood flow (NBF) were assessed in anesthetized swine using continuous laser Doppler flowmetry. The levels of arterial occlusion were selected to simulate clinical therapeutic occlusions used for the management of epistaxis.

METHODS

Nineteen swine were entered into one of four experimental groupings: proximal IMA occlusion using platinum micro-coils (n = 6), mid-grade distal IMA occlusion with polyvinyl alcohol particulate (PVA) suspensions (300 to 500 microns, n = 5), high-grade distal IMA occlusion with polyvinyl alcohol particulate suspensions (50 to 150 microns, n = 5), and sham control (n = 2).

RESULTS

All embolizations resulted in acute decreases in average NBF from 120 mL/min per 100 g to 40 mL/min per 100 g (P < .05 for all groups). NBF returned to baseline in all three treated groups within 2 to 8 days after therapeutic embolization, depending on the level of occlusion (coils, 2 d; mid-grade PVA, 2-3 d; high-grade PVA, 8 d). Follow-up angiography showed recanalization and collateralization as possible methods of reestablishing NBF.

CONCLUSIONS

This study supports the rationale for performing distal IMA occlusion with transarterial particulate embolization, in order to provide a longer period of time of diminished NBF. This theoretically should promote hemostasis within an injured portion of the nasal mucosa by decreasing perfusion pressure within the capillary bed. However, the benefits of distal IMA embolization must be balanced against potential ischemic complications, as may be more commonly seen with high-grade particulate embolization.

Pigmented villonodular synovitis of the temporomandibular joint: diagnostic imaging and endovascular therapeutic embolization of a rare head and neck tumor

We report a case of pigmented villonodular synovitis involving the temporomandibular joint that presented as a rapidly growing tumor with extension through the skull base into the middle cranial fossa. The case is of interest not only because of the unusual extensive infiltration of this tumor but also because of the role modern diagnostic imaging and endovascular therapeutic techniques played in its diagnosis and management.

Failure of the hypotensive provocative test during temporary balloon test occlusion of the internal carotid artery to predict delayed hemodynamic ischemia after therapeutic carotid occlusion

BACKGROUND

Extensive experience and critical evaluation of the efficacy of a pharmacologic hypotensive challenge during conventional balloon test occlusion (BTO) of the internal carotid artery (ICA) is lacking. This prompted us to review our institution's most recent experience with this adjunctive provocative test before planned therapeutic balloon occlusion of the ICA.

METHODS

Twenty consecutive cases of endovascular therapeutic balloon occlusion of the ICA were retrospectively reviewed. Conventional BTO under normotension and with hypotensive challenge were performed within a standardized protocol.

RESULTS

Sixteen patients underwent provocative testing, of which 13 had BTO with hypotensive challenge. All patients in this group tolerated these maneuvers without acute neurologic deficit. Two (15%) of these patients developed delayed permanent neurologic deficits, which seemed to be attributable to hemodynamic ischemia. One of seven patients not undergoing hypotensive challenge also developed transient neurologic deficits after carotid occlusion.

CONCLUSIONS

Despite the conceptually attractive and early positive experience of the hypotensive challenge in attempting to increase sensitivity and specificity of risk for developing delayed hemodynamic ischemia, we have found two significant false-negative results. This experience is reviewed in the context of risks of permanent balloon occlusion of the carotid artery after balloon test occlusion.

Percutaneous direct-puncture acrylic embolization of a pseudoaneurysm after failed carotid stenting for the treatment of acute carotid blowout

We report a difficult case of recurrent carotid blowout syndrome in a patient who had a rupture of the common carotid artery with formation of a large pseudoaneurysm. Conventional management of this emergency, consisting of composite occlusion of the internal and common carotid arteries, was not possible owing to prior clinical failure of balloon test occlusion. This led to an initial attempt to cover the site of rupture with overlapping self-expanding stents, which was only temporarily successful in controlling the hemorrhage. When a subsequent episode of carotid rupture with life-threatening hemorrhage occurred, percutaneous direct-puncture acrylic embolization with temporary flow arrest was used to successfully obliterate the pseudoaneurysm.

MR of hereditary hemorrhagic telangiectasia: prevalence and spectrum of cerebrovascular malformations

PURPOSE

Our goal was to describe the prevalence and types of cerebral vascular malformations (CVMs) seen with MR imaging in patients with hereditary hemorrhagic telangiectasia (HHT).

METHODS

We reviewed retrospectively the brain MR images of 184 consecutive patients with HHT. Catheter angiography was performed in 17 patients with CVMs detected on MR images.

RESULTS

MR imaging revealed 63 CVMs in 42 patients. Classic arteriovenous malformations (n = 10) had a conspicuous network of vessels with flow voids and enlarged adjacent pial vessels. Apparent venous malformations (n = 5) were best seen after administration of contrast material as a prominent vessel coursing through normal brain parenchyma. Indeterminate vascular malformations (n = 48) had a spectrum of appearances characterized by variable combinations of heterogeneous signal intensity, enhancement, or hemosiderin. Angiography in 17 patients revealed 47 CVMs. Forty-six were arteriovenous malformations (AVMs), including 25 CVMs not seen with MR imaging and 21 CVMs that by MR criteria included 8 AVMs and 13 indeterminate vascular malformations. Angiography confirmed 1 venous malformation seen with MR imaging but failed to detect 3 indeterminate lesions revealed by MR imaging.

CONCLUSION

MR imaging of a large cohort of consecutive patients with HHT revealed a CVM prevalence of 23% (42/184). Most CVMs (48/63) have an atypical appearance for vascular malformations on MR images. Angiographic correlation suggests that MR imaging underestimates the prevalence of CVMs and that the majority of indeterminate CVMs, despite their variable MR appearance, are AVMs.

Postoperative changes in the brain: MR imaging findings in patients without neoplasms

PURPOSE

To determine the time course of postoperative changes in the brain by using magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Contrast material-enhanced MR images (32 preoperative, 161 postoperative) in 95 patients who underwent temporal lobectomy for treatment of nonneoplastic epilepsy were evaluated for enhancement pattern at the surgical margin and for the presence of dural enhancement, fluid, and air. Images were obtained 9 hours to 5.6 years after surgery.

RESULTS

Surgical margin contrast enhancement was present and increased from 20 hours to 29 days after surgery. The predominant early (days 0-5) pattern was thin linear enhancement (16 of 18 [89%] images). The later (days 6-29) pattern was thick linear or nodular (tumorlike appearance) (11 of 18 [61%] images). Surgical margin enhancement was absent after day 30, although few data were collected 1-5 months after surgery. Dural enhancement was seen on 96 of 97 (99%) postoperative MR images. Extraaxial fluid was seen on all 46 images obtained during the first 30 days and was absent by day 51. Intracranial air was present on 31 of 35 (89%) images obtained during the first 4 days but was absent after day 5.

CONCLUSION

Knowledge of the evolution of contrast enhancement patterns on postoperative MR images of the brain can help in differentiating benign from neoplastic changes.

Technical feasibility and performance studies of a 0.009-inch nitinol microguidewire for potential neuroendovascular applications

RATIONALE AND OBJECTIVES

The authors conduct technical feasibility and performance studies on a new 0.009-inch nitinol microguidewire for potential neuroendovascular applications.

METHODS

In vivo microcatheterizations of brachiocephalic arteries were performed in four pigs using the 0.009-inch nitinol microguidewire with a commonly used microcatheter and compared with the performance of commercially available microguidewires. Vessels catheterized using the 0.009-inch wire were evaluated by histopathological analysis. A standardized, bench-top method of evaluating basic mechanical properties of microguidewires also was used to compare the 0.009-inch nitinol microguidewire with two commonly used microguidewires.

RESULTS

The 0.009-inch microguidewire had similar steerability, tractability, torque control, and distal tip flexibility to the commonly used microguidewires in the in vivo simulations. Bench top testing showed the 0.009-inch microguidewire to have comparable distal tip flexibility and objective mechanical properties to the commonly used microguidewires.

CONCLUSIONS

The comparable subjective and objective mechanical properties of the 0.009-inch nitinol microguidewire to that of commonly used microguidewires further establishes the possibility of clinical implementation.

Pituitary gland enlargement secondary to dural arteriovenous fistula in the cavernous sinus: appearance at MR imaging

PURPOSE

To evaluate pituitary gland size in cases of dural arteriovenous (AV) fistula in the cavernous sinus and to correlate the size with the degree of AV fistula.

MATERIALS AND METHODS

Magnetic resonance images in 21 patients with angiographically proved dural AV fistula of the cavernous sinus were retrospectively reviewed. In four patients, findings obtained before and after embolization therapy were compared.

RESULTS

The 21 patients were divided into group 1 (severe AV fistula) and group 2 (moderate or mild AV fistula). The superior contour of the pituitary gland was convex or flat in group 1 and flat or concave in group 2. The mean height of the pituitary gland was 9.4 mm +/- 1.5 (standard deviation) in group 1 and 6.7 mm +/- 1.2 in group 2 (P = .0002). After embolization therapy, pituitary gland height decreased and signal intensity voids improved in the four patients and no AV fistula was observed in three.

CONCLUSION

In cases of severe dural AV fistula in the cavernous sinus, the pituitary gland is enlarged, which should not be misdiagnosed as pathologic.

Paradoxical clinicoradiologic features of a cavernous dural arteriovenous malformation

A case of bilateral Barrow type D dural arteriovenous malformations (DAVMs) of the cavernous sinuses is described in a 66-year-old woman who, despite having moderate symptoms with partial resolution and benign findings on non-invasive imaging, was ultimately found to have associated leptomeningeal venous drainage on conventional angiography. This case illustrates the problem of discordance between clinical symptoms, non-invasive imaging and actual radiologic features predisposing to aggressive clinical behaviour in DAVMs detected by conventional angiography.

Occult spontaneous lateral temporal meningoencephalocele: MR findings of a rare developmental anomaly

We describe a case of an occult lateral temporal meningoencephalocele discovered in a 14-year-old boy during a work-up for minor head trauma. This spontaneous encephalocele resulted from a closure defect at the former sphenoidal fontanelle. Preoperative MR images are presented.

True malignant mixed tumor (carcinosarcoma) of tonsillar minor salivary gland origin: diagnostic imaging and endovascular therapeutic embolization

We report a case of carcinosarcoma of the minor salivary glands of the left palatine tonsil, an especially rare location. Imaging characteristics assessed at CT, MR imaging, and angiography are presented. In addition, we describe our experience with preoperative therapeutic endovascular embolization of this hypervascular tumor.

Exceptional multiplicity of cerebral arteriovenous malformations associated with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)

PURPOSE

To describe the clinical and imaging features of seven patients with hereditary hemorrhagic telangiectasia and an exceptional number of cerebral arteriovenous malformations (AVMs).

METHODS

One hundred thirty-six patients from a dedicated hereditary hemorrhagic telangiectasia clinic were screened systematically for cerebral AVMs by means of MR imaging. Thirty-one were found to have abnormalities suggestive of a vascular malformation. Eighteen of these 31 patients subsequently underwent diagnostic cerebral angiography.

RESULTS

Of the 18 patients who had cerebral angiography, all were found to have at least one AVM and seven were found to have three or more AVMs. The number of cerebral AVMs detected ranged from three to nine. At angiography, the AVMs varied in size from 3 to 25 mm in maximal dimension and consisted of a poorly defined plexiform nidus that typically had a single arterial feeding pedicle and a single draining vein. The two largest AVMs (20- and 25-mm nidus, respectively) contained intranidal aneurysms. Treatment included embolization, surgical excision, or follow-up management.

CONCLUSIONS

Multiple cerebral AVMs are associated with hereditary hemorrhagic telangiectasia and further highlight the uniqueness of central nervous system involvement by this systemic angiodysplasia. MR imaging can underestimate the number and size of cerebral AVMs; therefore, catheter angiography is necessary to establish the extent of central nervous system involvement in this disorder.

Endovascular therapeutic approach to peripheral aneurysms of the superior cerebellar artery

Peripheral aneurysms of the superior cerebellar artery may be difficult to treat surgically owing to their inaccessibility and to the frequent inability to preserve the involved parent artery. In fact, for most cases, surgical treatment consists of proximal parent artery occlusion and/or trapping with surgical clips. An equivalent endovascular therapeutic approach to these lesions may be an attractive alternative method of management. We describe two cases of peripheral superior cerebellar artery aneurysms that were treated successfully with endovascular embolization.

Hypervascular tumor of the buccal space in an adult as a late recurrence of juvenile angiofibroma

We describe an adult patient with recurrent juvenile angiofibroma, which presented as a rapidly enlarging, hypervascular mass in the anterior part of the cheek. The case is unusual because of the extreme delay (greater than 30 years) and the anatomic location of the recurrence.

Endovascular therapy for the carotid blowout syndrome in head and neck surgical patients: diagnostic and managerial considerations

PURPOSE

To review our institution's recent experience with patients with carotid blowout syndrome who were referred for emergency diagnostic angiography and endovascular therapy.

METHODS

Eighteen consecutive patients who had had surgery for cancer of the head and neck and in whom carotid blowout syndrome had occurred were referred to our service in accordance with a standardized protocol.

RESULTS

Twenty-three angiographic pathoetiologic conditions were diagnosed in the 18 patients; the majority of these were pseudoaneurysms involving various segments of the carotid system. Multiple lesions were detected in five patients. Most patients were treated by means of permanent balloon occlusion; in 8 patients with either multiple lesions or impending rupture requiring flap reconstruction, a composite permanent balloon occlusion of the affected carotid system was performed. Hyperacute hemorrhages were arrested in all cases. Hemorrhages reoccurred in 2 cases, and in 2 patients who had permanent balloon occlusion of the internal carotid artery, transient ischemic attacks occurred, which appeared to be related to temporary collateral reserve failure. No permanent neurologic complications ensued.

CONCLUSION

Our recent experience with carotid blowout syndrome suggests that this clinical diagnosis represents a heterogeneous group of angiographic pathoetiologies that the physician should evaluate carefully before proceeding with endovascular therapy. Specific endovascular approaches depend on the pathoetiologic mechanism of active or impending hemorrhage and the urgency with which intervention is required.

Use of large-caliber coronary guiding catheters for neurointerventional applications

The use of certain large-caliber (ie, 7F to 9F) coronary guiding catheters for selected neuroendovascular procedures is described in the context of surveying recently developed neurovascular guiding catheters. These large-caliber guiding catheters have proved useful in situations requiring proximal access to tortuous brachiocephalic arteries, permitting coaxial delivery of relatively large neurointerventional devices, such as most detachable balloons and 5F percutaneous transluminal angioplasty catheters. These large-caliber coronary guiding catheters have some important advantages over both old and new neurovascular guiding catheters, including favorably preshaped configurations and superior torque control. These features permit relatively easy direct selective catheterization of unfavorable vascular anatomy resulting from dolichoectasia of the aortic arch and great vessels.

Sentinel transoral hemorrhage from a pseudoaneurysm of the internal maxillary artery: a complication of CT-guided biopsy of the masticator space

A patient presented with transoral hemorrhage 3 months after CT-guided percutaneous biopsy of the masticator space, prompting concern about sentinel hemorrhage from impending carotid artery rupture related to prior radical head and neck surgery and radiation therapy. Angiographic evaluation showed the internal carotid artery to be normal but demonstrated a pseudoaneurysm of the buccal branch of the internal maxillary artery exactly corresponding to the site of prior fine-needle biopsy.

Endovascular therapy for surgical diseases of the cranial base

Endovascular therapy for surgical diseases of the cranial base is in many ways a survey of the field of interventional neuroradiology (or endovascular neurosurgery). As the multidisciplinary focus to the treatment of various cranial base diseases has become increasingly complex, the role of endovascular therapy as both a primary and secondary treatment modality has expanded. A comprehensive review of this role is presented.