Abciximab rescue in acute carotid stent thrombosis

Occlusion of an internal carotid artery stent was identified immediately post placement in a patient who had restenosis after prior angioplasty. An IV dose of abciximab was administered, and serial angiograms were performed. This resulted in partial resolution of the thrombus at 10 minutes and complete resolution at 20 minutes.

Use of three-dimensional Guglielmi detachable coils in the treatment of wide-necked cerebral aneurysms

A three-dimensional Guglielmi detachable coil (3D-GDC) has been developed that is designed specifically to bridge the neck of an aneurysm with coil loops, thereby facilitating retention of additional coils placed within the aneurysm. Nine wide-necked cerebral aneurysms were successfully embolized using the 3D-GDC, provided that the dome-to-neck ratio was 1.5 or greater.

Preoperative and palliative embolization of vertebral tumors

Embolization of vertebral tumors is useful as an adjunct to surgery because it can minimize blood loss. Embolization also may decrease surgical operating time and reduce complications by improving visualization in the operative field. It also is occasionally useful as a palliative measure to relieve pain or neurologic compromise in patients with unresectable tumors. Spinal embolization is a relatively safe procedure when performed with proper technique by experienced operators.

Timing of ICAM-I Expression in a Canine Model of Post-Haemorrhagic Cerebral Vasospasm

SUMMARY

Temporal alterations in endothelial intercellular adhesion molecule I (ICAM-I) expression during the course of post-haemorrhagic cerebral vasospasm (PHCV) are correlated with angiographic and histologic changes in the canine basilar artery. Angiography was performed in six dogs to obtain baseline measurements of basilar artery diameter. In three dogs subarachnoid haemorrhage (SAH) was created by performing percutaneous puncture of the cisterna magna, and replacing 7 ml of cerebrospinal fluid with 7 ml of arterial blood. The remaining three dogs were used as controls. Daily angiography was performed on all dogs to determine the percent reduction in basilar artery diameter (%RBAD). One dog from each group was sacrificed after 24 hours. The remaining two dogs in each group were sacrificed after 48 hours. Each basilar artery was perfusion fixed and subjected to histologic, and immunohistochemical analysis. In the SAH group, the average %RBAD was 4 (+/- 3) at 24 hours, and 36 (+/- 1) at 48 hours. In the control group, the average %RBAD was - 1 (+/- 1) at 24 hours, and 0 (+/- 2) at 48 hours. Endothelial edema and endothelial expression of ICAM-I were found at 24 hours.At 48 hours post-SAH there was widespread endothelial desquamation, but no evidence of ICAM-I expression. In the control group, histology was normal and no ICAM-I expression was found at 24 or 48 hours. The results suggest that a brief window of therapeutic efficacy exists during the first postictal 24 hours where ICAM-I antagonists may be useful in suppressing the pathogenesis of PHCV.

Endovascular treatment of intracranial aneurysms with Guglielmi Detachable Coils: emphasis on new techniques

Endovascular therapy for intracranial aneurysms has evolved since Serbinenko pioneered embolisation with latex balloons in the 1970s. The focus of modern endovascular therapy has shifted to the use of Guglielmi Detachable Coils (GDC; Boston Scientific Corporation, Natick, MA, USA) which are retrievable until the operator is satisfied with placement and they are detached. GDC therapy has been shown to be most efficacious in smaller aneurysms with relatively large dome:neck ratios which allow maximal coil packing within the aneurysm lumen. Wide neck aneurysms with dome:neck ratios of less than 2.0 and large aneurysms have a significantly lower incidence of complete treatment, with higher rates of repeat rupture following GDC therapy. The geometry of wide neck aneurysms is less favourable for retention of coils within the aneurysm lumen, resulting in greater risk of parent vessel compromise from coil herniation and difficulty obtaining maximal coil packing. This chapter will summarise GDC therapy for intracranial aneurysms including newer techniques designed to address the problem of wide neck aneurysms.

Adjuvant use of epsilon-aminocaproic acid (Amicar) in the endovascular treatment of cranial arteriovenous fistulae

We report our experience with the use of the antifibrinolytic agent epsilon-aminocaproic acid (EACA), Amicar, as an adjuvant to endovascular treatment of cranial arteriovenous fistulae. We also review applications of antifibrinolytic agents to neurovascular disorders and discuss the mechanism of action, dosing strategy, contraindications, and possible complications associated with the use of EACA. We identified 13 patients with cranial arteriovenous fistulae (five direct carotid cavernous fistulae [CCF], seven dural arteriovenous fistulae [DAVF], and one vein of Galen malformation) who received EACA as an adjunct to endovascular treatment. In all cases embolic coils were the primary embolic agent. We reviewed the modes of initial endovascular therapy and angiographic findings immediately thereafter and the response to EACA. Two direct CCF and two DAVF were completely thrombosed on follow-up angiography, and two DAVF demonstrated diminished flow after EACA therapy. Seven fistulae did not respond to EACA. Four of eight tightly coiled fistulae thrombosed, while none of five loosely coiled fistulae thrombosed. None of four cases with a residual fistula separate from the coil mass underwent thrombosis with EACA, while four of nine cases without a separate fistula thrombosed. There was no morbidity related to EACA therapy. EACA may thus be useful as an adjunct to endovascular treatment of cranial arteriovenous fistulae. Loose or incomplete coil packing of the fistula predicts a poor response to EACA therapy.

Arterial dissections complicating cerebral angiography and cerebrovascular interventions

BACKGROUND AND PURPOSE

Iatrogenic dissections are an uncommon complication of cerebral angiography. We retrospectively reviewed 12 cases of arterial dissections complicating cerebral angiography and cerebrovascular interventions to evaluate the clinical course of these dissections.

METHODS

Cases from a large tertiary center performing a large number of neurovascular procedures were collected retrospectively. The patients' medical records and imaging studies were reviewed, with particular attention given to the cause of the dissection, the development of ischemic events resulting from the dissection, and the treatment used.

RESULTS

Each of nine dissections affected a vertebral artery, each of two affected an internal carotid artery, and one affected a common carotid artery. The prevalence of iatrogenic dissections was 0.4%. Seven of the dissections were noted at the time of contrast material injection for the filming of cerebral angiograms. The other five dissections occurred during catheter or wire manipulations for interventional neuroradiologic procedures. Five of the patients in our series were treated with IV administered heparin for 24 to 48 hours. The other seven patients had recently suffered acute intracranial hemorrhage or undergone neurosurgery and could not undergo anticoagulant therapy. None of the patients developed symptoms of ischemia, but one was later found to have an asymptomatic infarct in the territory supplied by the dissected artery.

CONCLUSION

Arterial dissections are an uncommon complication of cerebral angiography and cerebrovascular interventions and usually have a benign clinical course.

Bovine type I collagen as an endovascular stent-graft material: biocompatibility study in rabbits

PURPOSE

To study the biocompatibility of a bovine type I collagen preparation as a material for small-vessel stent-grafts in rabbits.

MATERIALS AND METHODS

A composite nitinol-collagen endovascular stent-graft with a 4-mm inner diameter was deployed in the abdominal aorta in nine rabbits. Angiography was performed, and the rabbits were sacrificed at 1, 2, and 7 days and at 1 and 3 months. The portion of the aorta containing the stent-graft was excised and was histologically evaluated.

RESULTS

All stent-grafts were patent at all time points. On days 1, 2, and 7 after implantation, scattered red and white blood cells adhered to the stent-graft. At 1 month, the stent-graft was endothelialized and was infiltrated with fibroblasts that deposited collagen within the interstices of the implanted collagen material. At 3 months, there was additional collagen deposition within the interstices of the stent-graft that did not narrow the lumen of the stent-grafts.

CONCLUSION

Type I collagen as a intravascular stent-graft material is biocompatible for at least 3 months in rabbits. It is rapidly endothelialized and does not cause reactive stenosis. As a versatile and biocompatible polymer, collagen is potentially useful in the construction of endovascular stent-grafts for use in human arteries.

1999 ARRS Executive Council Award. Creation of saccular aneurysms in the rabbit: a model suitable for testing endovascular devices. American Roentgen Ray Society

OBJECTIVE

This study developed an animal model of intracranial aneurysms suitable for evaluating emerging endovascular devices for aneurysmal therapy. We characterized the short-, medium-, and long-term attributes of this endovascular technique for saccular aneurysmal creation in the rabbit.

MATERIALS AND METHODS

The right common carotid artery was surgically exposed in nine New Zealand white rabbits. Using endovascular techniques, we occluded the origin of the right common carotid artery with a pliable balloon. Elastase was incubated endoluminally in the proximal common carotid artery above the balloon. The common carotid artery was ligated distally. Animals were studied angiographically and sacrificed at 2 weeks (n = 3), 10 weeks (n = 3), and 24 weeks (n = 3) after aneurysm creation. Histology was obtained.

RESULTS

Saccular aneurysms formed in eight of the nine rabbits. The aneurysm projected from the apex of an approximately 90 degree curve of the parent vessel, the brachiocephalic artery. Mean aneurysm diameter was 4.5 mm (SD, 1.2 mm), and mean height was 7.5 mm (SD, 1.6 mm). All samples showed thinned elastic lamina and no evidence of inflammation. In four of eight aneurysms, unorganized thrombus was present in the dome of the aneurysm.

CONCLUSION

Arterial aneurysms with intact endothelium and deficient elastic lamina were reliably created in an area of high shear stress in New Zealand white rabbits. Three of these aneurysms remained patent for at least 6 months. We found a simple procedure that can be readily applied to the testing of new endovascular devices for a reliable creation of aneurysms in rabbits.

Endovascular creation of an in vivo bifurcation aneurysm model in rabbits

PURPOSE

To develop a rabbit model of an intracranial bifurcation aneurysm to test new endovascular therapies.

MATERIALS AND METHODS

An experimental aneurysm model was created in rabbits by means of endovascular balloon occlusion of the left common carotid artery, which created an aneurysm at the bifurcation formed by the aortic arch and the brachiocephalic trunk. A total of 18 aneurysms were created. In eight rabbits, the aneurysms were incubated with intraluminal elastase to induce degeneration of the elastic laminae. The animals were followed up with angiography for as long as 3 months. The animals were sacrificed at various times, and histologic evaluation of the aneurysm was performed.

RESULTS

Ten aneurysms created without elastase infusion were all very small or completely closed at 1-3 months. Six aneurysms created with elastase infusion had long-term patency (two were patent at 1 month and four, at 3 months). The elastase aneurysms had a mean width of 3 mm (range, 2-3.5 mm) and a mean length of 5 mm (range, 3-7 mm). Histologic evaluation revealed destruction of the normal elastin layers, which allowed the artery to become aneurysmal.

CONCLUSION

This aneurysm model re-created the hemodynamic forces and size of human cerebral bifurcation aneurysms and maintained the integrity of the endothelium. The creation of the aneurysms was rapid, reliable, and reproducible.

Idiopathic supraclinoid and internal carotid bifurcation steno-occlusive disease in young American adults

We report a series of American adults with idiopathic steno-occlusive disease of the supraclinoid internal carotid artery and its bifurcation. We reviewed the clinical records and imaging of 18 patients, 16 women and 2 men, aged 20-53 years (mean 35 years). There were no predominating risk factors for vascular occlusive disease, such as oral contraceptive use, hypertension, diabetes mellitus, or smoking. Four patients had irregularity of their cervical internal carotid arteries in a pattern not classic but suspicious of fibromuscular dysplasia. Eleven patients met the criteria for moyamoya disease, having both bilateral disease and moyamoya collateral lenticulostriate arteries. Necropsy in one case showed intimal thickening with duplication of the internal elastic lamina involving the internal carotid artery bifurcation bilaterally. We found a marked predominance of young and middle-aged females in our American adults, but our findings do not support the association with birth-control pills previously reported.

Histologic evaluation of platinum coil embolization in an aneurysm model in rabbits

PURPOSE

To characterize the histologic response to platinum coil embolization by using a rabbit aneurysm model.

MATERIALS AND METHODS

Saccular aneurysms were created in New Zealand White rabbits by using vessel ligation with intraluminal elastase incubation. Aneurysms were subsequently embolized by using platinum coils. Subjects were sacrificed at various intervals up to 12 weeks following coil embolization. The aneurysm cavities and adjacent vessels were embedded in methylmethacrylate, were sectioned, and were stained for histologic examination.

RESULTS

Two weeks following coil implantation, aneurysms were filled predominantly with unorganized thrombus. Six weeks following coil implantation, histologic features included complete filling of the aneurysm lumen with either prominent laminated but unorganized thrombus or areas of unorganized thrombus interspersed among areas of cellular infiltration. At 12 weeks following coil implantation, aneurysms were filled with the loosely packed, disordered cells contained within the extracellular matrix. Fibrosis or smooth muscle cell infiltration was not present in any of the 6- or 12-week samples.

CONCLUSION

Platinum coils placed into experimental saccular aneurysms in New Zealand White rabbits failed to elicit a fibrotic response. This model can be used for the testing of biologic modifications of platinum coils aimed at increasing intra-aneurysmal fibrosis.

The fate of neuroradiologic abstracts presented at national meetings in 1993: rate of subsequent publication in peer-reviewed, indexed journals

BACKGROUND AND PURPOSE

Abstract presentations are a valuable means of rapidly conveying new information; however, abstracts that fail to eventually become published are of little use to the general medical community. Our goals were to determine the publication rate of neuroradiologic papers originally presented at national meetings in 1993 and to assess publication rate as a function of neuroradiologic subspecialty and study design.

METHODS

Proceedings from the 1993 ASNR and RSNA meetings were reviewed. A MEDLINE search encompassing 1993-1997 was performed cross-referencing lead author and at least one text word based on the abstract title. All ASNR and RSNA neuroradiologic abstracts were included. Study type, subspecialty classification, and sample size were tabulated. Publication rate, based on study design and neuroradiologic subspecialty, was compared with overall publication rate. Median duration from meeting presentation to publication was calculated, and the journals of publication were noted.

RESULTS

Thirty-seven percent of ASNR abstracts and 33% of RSNA neuroradiologic abstracts were published as articles in indexed medical journals. Publication rates among neuroradiologic subspecialty types were not significantly different. Prospective studies presented at the ASNR were published at a higher rate than were retrospective studies. There was no difference between the publication rate of experimental versus clinical studies. Neuroradiologic abstracts were published less frequently than were abstracts within other medical specialties. Median time between abstract presentation and publication was 15 months.

CONCLUSION

Approximately one third of neuroradiologic abstracts presented at national meetings in 1993 were published in indexed journals. This rate is lower than that of abstracts from medical specialties other than radiology.

Experimental side-wall aneurysms: a natural history study

We studied the natural history of canine side-wall experimental aneurysms to determine the incidence of spontaneous aneurysm thrombosis, to serve as control data for future studies focusing on development of aneurysm occlusion devices. Bilateral common carotid artery vein patch aneurysms were surgically created in eight mongrel dogs (20-25 kg). Duplex Doppler sonography was performed at 14 days and angiography between 30 and 210 days following aneurysm creation. Sonography demonstrated patency of 13 (81%) of 16 aneurysms. Patent aneurysms ranged in size from 8 x 10 mm to 14 x 16 mm. Conventional angiography was performed in four dogs approximately 30 days following aneurysm creation; in these four, all of 7 initially patent on sonography remained fully patent. One dog underwent conventional angiography at approximately 60 days following aneurysm creation; both aneurysms in this case remained widely patent. Three dogs underwent conventional angiography at approximately 200 days following aneurysm creation; all 4 aneurysms initially patent on sonography remained fully patent. None of the three aneurysms found to be occluded on sonographs demonstrated spontaneous recanalization. The canine side-wall aneurysm model is a valid tool for testing some aneurysm-occlusion devices, because control aneurysms remain patent indefinitely.

Prevalence of cerebral aneurysms in patients with persistent primitive trigeminal artery

OBJECT

The aim of this study was to determine the prevalence of cerebral saccular aneurysms in patients with persistent primitive trigeminal artery (PPTA). The prevalence of cerebral saccular aneurysms in patients with PPTA previously has been reported to be 14 to 32%, but this rate range is unreliable because it is based on collections of published case reports rather than a series of patients chosen in an unbiased manner.

METHODS

The authors retrospectively evaluated their own series of 34 patients with PPTA to determine the prevalence of cerebral aneurysms in this population. The prevalence of intracranial aneurysms in patients with PPTA was approximately 3% (95% confidence interval 0-9%).

CONCLUSIONS

The prevalence of intracranial aneurysms in patients with PPTA is no greater than the prevalence of intracranial aneurysms in the general population.

Angiographic correlation of CT calcification in the carotid siphon

BACKGROUND AND PURPOSE

Calcification in the coronary arteries has been correlated with significant vessel stenosis. The predictive value of calcification within the carotid siphon has not been characterized; however, stenosis in the carotid siphon is potentially important in determining management of patients with ipsilateral carotid bifurcation stenosis. The purpose of this study was to determine optimal parameters for assessing carotid siphon calcification on head CT scans and to compare the CT findings with angiographic results.

METHODS

We performed a retrospective review of patients referred for diagnostic carotid arteriography. Those patients who also had undergone a head CT study at our institution were selected. The CT scans and angiograms of 64 patients (128 vessels) were reviewed. Carotid siphon calcification on CT scans was characterized on brain and bone windows as mild, moderate, or severe. Comparison was then made with angiographic findings.

RESULTS

The sensitivity and specificity of CT for depicting greater than 50% angiographic stenosis in the carotid siphon were 86% and 98%, respectively, for bone windows and 100% and 0%, respectively, for brain windows. The positive predictive value (PPV) for a stenosis of greater than 50% as evidenced by severe calcification was 86% on bone windows and 11% on brain windows. The PPV for mild and moderate calcification on bone windows was 2.5% and 0%, respectively.

CONCLUSION

Severe CT calcification in the carotid siphon as characterized on bone windows correlates with a carotid siphon stenosis of greater than 50% as determined angiographically. Therefore, the identification of severe calcification offers a potential noninvasive method for identifying stenosis of the carotid siphon. This information may be essential in determining management and prognosis for patients with carotid bifurcation stenosis.

Dural arteriovenous fistula of the cervical spine presenting with subarachnoid hemorrhage

We describe a case of dural arteriovenous fistula (DAVF) presenting with subarachnoid hemorrhage (SAH). The diagnosis of DAVF was based on spinal angiography. A review of the literature revealed that five of 13 previously reported DAVFs of the cervical spine were accompanied by SAH. SAH has not been observed in DAVFs involving other segments of the spinal canal.

Risk of cerebral angiography in patients with subarachnoid hemorrhage, cerebral aneurysm, and arteriovenous malformation: a meta-analysis

BACKGROUND AND PURPOSE

A well-defined complication rate of cerebral angiography in patients with subarachnoid hemorrhage (SAH), cerebral aneurysm, and arteriovenous malformation (AVM) would be useful to physicians making decisions regarding the imaging of these patients. We sought to define a statistically significant complication rate through meta-analysis of prospective studies in the literature.

METHODS

Meta-analysis of 3 published prospective studies of complications in cerebral angiography was performed to specifically define the risk of cerebral angiography in patients presenting with SAH, cerebral aneurysm, and AVM. The complication rates for cerebral angiography in patients with SAH and AVM/aneurysm without SAH were compared with the complication rates in patients who underwent cerebral angiography for transient ischemic attack (TIA)/ischemic stroke with use of the Fisher exact test.

RESULTS

The combined risk of permanent and transient neurological complication was significantly lower in patients with SAH compared with patients with TIA/stroke (1.8% versus 3.7%; P=0.03). The combined risk of permanent and transient neurological complication was significantly lower in patients with aneurysm/AVM without SAH compared with patients with TIA/stroke (0.3% versus 3.7%; P=0.001). When the patients with SAH and cerebral aneurysm/AVM were combined, the overall risk of permanent and transient neurological complication was significantly lower than for the TIA/stroke patients (0.8% versus 3.0%; P=0.001), as was the risk of permanent neurological complication (0.07% versus 0.7%; P=0.004).

CONCLUSIONS

The risk of permanent neurological complication associated with cerebral angiography in patients with SAH, cerebral aneurysm, and AVM is quite low (0.07%). This risk is lower than previously recognized.

Endovascular treatment of ruptured, peripheral cerebral aneurysms: parent artery occlusion with short Guglielmi detachable coils

We report two cases of distal cerebral aneurysms that were treated by parent artery occlusion with short Guglielmi detachable coils (GDCs). One patient had a presumed mycotic aneurysm of the distal left posterior cerebral artery, and the other had a partially clipped aneurysm of the distal right anterior inferior cerebellar artery that had hemorrhaged. Short GDCs allow controlled, accurate occlusion of the parent artery at the aneurysmal neck.

Exposure of medical personnel to methylmethacrylate vapor during percutaneous vertebroplasty

The occupational exposure to methylmethacrylate (MMA) vapor during percutaneous vertebroplasty was determined. During five vertebroplasty procedures, air-sampling pumps were attached to medical personnel. MMA vapor levels in the samples were then quantified using gas chromatography. The samples collected yielded MMA vapor levels of less than five parts per million (ppm). The MMA vapor concentrations measured were well below the recommended maximum exposure of 100 ppm over the course of an 8-hour workday.

Correlation of angiography and MR imaging in cerebral vasculitis

PURPOSE

MR imaging and cerebral angiography were correlated in patients with primary angiitis of the central nervous system (PACNS) to assess the relative roles of these imaging modalities in the diagnosis.

MATERIAL AND METHODS

In 9 patients, MR imaging and angiography were compared with regard to the relative involvement of each major vascular territory. Vascular territories assessed were the anterior, middle, and posterior cerebral arteries, and the posterior fossa.

RESULTS

All patients had angiographic findings consistent with vasculitis in multiple vascular territories. MR findings ranged from normal to diffusely abnormal. One patient had a completely normal MR investigation. Of 50 territories affected by vasculitis on angiography, 17 (34%) were normal on MR.

CONCLUSION

Relative to cerebral angiography, MR imaging is a poor indicator of the presence or absence of PACNS. Angiography is indicated when clinical suspicion of PACNS is strong, regardless of the findings on MR.

CT-guided percutaneous drainage of syringomyelia

PURPOSE

Our purpose is to describe CT-guided percutaneous drainage of syringomyelia as a possible contribution in patient management.

METHOD

CT-guided percutaneous drainage was performed on three patients with symptomatic syringomyelia. We determined the success of percutaneous decompression by subsequent CT and MRI. The effect of syringomyelia decompression in relation to the patient's symptoms was determined. This information was then used to help guide clinical management.

RESULTS

In Case 1, percutaneous drainage of a large syrinx in a C5 quadriplegic patient with increasing lower extremity spasticity demonstrated significant decompression by imaging but did not result in clinical improvement. A surgical procedure to decompress the syrinx was not performed on the basis of this information. In Case 2, percutaneous drainage of a large syrinx in a quadriplegic patient with increasing upper extremity numbness and weakness demonstrated significant decompression by imaging and resulted in sustained clinical improvement, temporarily obviating the need for surgery. In Case 3, percutaneous drainage of the rostral aspect of a septated syrinx cavity in a patient with a Chiari I malformation and a syringoperitoneal shunt in place resulted in decompression by imaging but failed to relieve the patient's newly developed symptoms. An additional shunt was therefore not placed. In no case did the patient experience periprocedural complications or worsening of symptoms.

CONCLUSION

CT-guided percutaneous drainage of syringomyelia is a safe and successful technique. It can be used diagnostically to identify patients that may or may not benefit from surgical syrinx decompression and in some cases may provide a temporary therapeutic alternative to surgery.

Effects of systemic heparinization on the thrombogenicity of hydrophilic and nonhydrophilic catheters in a swine model

We assessed the effect of systemic heparinization on the in-vivo thrombogenicity of various micro- and guiding catheters in a swine model. Microcatheters were placed through 6-F guiding catheters into the common carotid arteries of swine for 30-min (short-term) and 90-min (medium-term) periods, with and without systemic heparinization. At the end of the placement period the microcatheters were retracted through the guiding catheters and fixed for scanning electron microscopy (SEM). Guiding catheters were harvested after 5 h placement, with and without systemic heparinization, by retraction through 8-F sheaths and fixed for SEM. The surfaces of both hydrophilic and nonhydrophilic microcatheters all demonstrated more accumulation of debris during placement without than with systemic heparinization. The difference was primarily in the amount of fibrillary material on the catheter surface. The guiding catheters also demonstrated increased debris accumulation without systemic heparinization. This suggests that, even when using relatively nonthrombogenic catheters, systemic heparinization is indicated during cerebral angiography.

In vivo evaluation of a new type I collagen hemostatic plug for high-risk, large-core biopsies

PURPOSE

To evaluate in a swine model the hemostatic properties of a new, expansile type I collagen plug for use in high-risk renal biopsies.

MATERIALS AND METHODS

Highly purified bovine type I collagen was formed into porous cylindrical plugs and compressed radially to fit into a 5-F delivery system. On hydration these collagen plugs demonstrated radial expansion with approximately 1,600% volumetric expansion ratio. Direct exposure of both kidneys was performed in a 25-kg swine, and a bolus of 3,000 U of heparin was administered to create a coagulopathic state. A 14-gauge Temno coaxial biopsy gun was utilized in performing nine pairs of renal biopsies. The first biopsy of each biopsy pair represented the control biopsy (without collagen plug placement), whereas the second biopsy of each pair represented the plugged biopsy. The presence and duration of hemorrhage from each biopsy site was monitored visually.

RESULTS

The biopsy sites without collagen plug showed immediate hemorrhage in nine of nine cases (100%), and in two of nine cases (22%) pulsatile bleeding was noted. With the use of the collagen plug, seven of nine (78%) sites showed immediate hemorrhage, but in no case was pulsatile bleeding noted. Mean bleeding duration was 156 seconds for the control biopsies versus 73 seconds for the biopsy sites plugged with collagen (P = .03, Mann-Whitney rank sum test). Bleeding duration was less than 1 minute in only one of nine (11%) control biopsies compared to six of nine (67%) collagen plug biopsies.

CONCLUSIONS

A recently developed, expansile collagen hemostatic plug significantly decreases the duration of hemorrhage at renal biopsy sites in an anticoagulated swine model.

Primary fibrosarcoma of the sella unrelated to previous radiation therapy

Fibrosarcomas involving the sella turcica are rare lesions and, when encountered, have been associated with previous radiation of a pituitary adenoma. Although primary intracranial fibrosarcomas are well recognized, no case of primary fibrosarcoma of the sella turcica has been reported to date. We describe here a patient who presented with a 2-month history of headache, visual disturbances, and diabetes insipidus. Her past medical history was unremarkable, with no radiation therapy. Magnetic resonance imaging revealed a sellar/suprasellar lesion that at surgery appeared firm in consistency. A radical removal of the mass was performed through a transsphenoidal approach. The patient recovered promptly from the operation and 2 weeks later, given the aggressive histologic appearance of the lesion, underwent gamma knife radiosurgery. Seven months after diagnosis, the patient presented with local tumor recurrence. A subtotal surgical resection was performed, and additional postsurgical treatment is still under consideration. Although most often related to previous radiation of the pituitary gland, primary fibrosarcomas can occur in the sella. This possibility should be suspected in the differential diagnosis of sellar masses that lack the classical characteristics of the much more common pituitary adenomas.

Platinum coil-mediated implantation of growth factor-secreting endovascular tissue grafts: an in vivo study

PURPOSE

To demonstrate in vivo that platinum embolic coils can be used to deliver genetically modified, growth factor-secreting fibroblast grafts into the endovascular space with the long-term goal of improving fibrosis within coil-embolized cerebral aneurysms.

MATERIALS AND METHODS

Murine fibroblasts that contained multiple inserts of the DNA for human basic fibroblast growth factor were grown in culture onto 10-mm-long segments of Guglielmi detachable coils. Control (n = 4) and fibroblast-bearing (n = 4) coils were implanted into the common carotid artery in nude rats. The arterial segments that contained the coil were harvested after 14 or 35 days. Cellular content and collagen formation in the treated vessels were assessed histologically.

RESULTS

At both 14 and 35 days, samples with control coils showed primarily involuting blood elements with minimal fibroblast proliferation or collagen formation. At 14 days, samples with fibroblast-bearing coils showed extensive fibroblast proliferation. At 35 days, samples with fibroblast-bearing coils showed marked interval fibroblast proliferation and collagen formation.

CONCLUSION

Platinum coils can be used as a cell delivery device. Direct intravascular implantation of growth factor-secreting fibroblast grafts leads to improved intravascular scar formation, therefore theoretically reducing the potential for aneurysm regrowth or coil compaction.

Transforming growth factor-Beta binds reversibly in vitro to guglielmi detachable coils

SUMMARY

We determined the propensity for and reversibility of transforming growth factor-beta(TGFbeta) binding to uncoated Guglielmi Detachable Coils (GDC) and to GDC coated with extracellular matrix (ECM) proteins. Three 1.0 centimetre samples each of uncoated GDC-18 and of GDC-18 coated with either poly-L-lysine, laminin, type I collagen, type IV collagen, fibronectin, or poly-L-lysine and laminin were prepared. These samples were immersed briefly in a solution containing I(125)-labelled TGFbeta at a concentration of 0.225 mug/ml with initial specific activity of 123.3 mCi/mg (DuPont-NEN, Billerica, MA), and were counted using a scintillation counter. Each sample was then placed in a vial containing saline, shaken for 60 seconds, and counted again. Selected samples were immersed for varying periods within the TGFbeta solution and counted before and after saline rinse. Samples were rinsed one week after initial rinsing and counted again. The amount of binding between coil types was compared using the Student t test. For all samples initial binding of TGFbeta was in the order of 60-120 pg/cm. For the pre-rinse data there were no statistically significant differences between the amount bound to any single coil coating type relative to other coatings. Compared to the initial accumulations, the amount remaining after rinsing ranged from 40% (poly-L-lysine) to 63% (poly-L-lysine with laminin), with a mean of 55% among the seven coil types. After rinsing there was more growth factor remaining on uncoated coils than on poly-L-lysine-coated coils (p=0.05), fibronectin-coated coils (p=0.01), and type IV collagen-coated coils (p=0.04). There was a trend toward greater residual growth factor on coils coated with poly-L-lysine and laminin compared to coils coated with poly-L-lysine alone (p=0.10). Delayed, second rinsing of the samples one week after initial testing demonstrated only minor incremental loss of TGFbeta from the coil surfaces. After five minutes of immersion, accumulation was approximately 200% greater than that noted with brief submersion, but immersions lasting over five minutes did not yield increasing levels of TGFbeta binding. TGFbeta binds to GDC coils. Binding is not improved with ECM protein-coated coils compared to uncoated coils. The absolute amount of TGFbeta bound to the coil will likely result in local concentrations of growth factor in the order of those required for biological activity in vivo.

Prevalence of cerebral aneurysms in patients with fibromuscular dysplasia: a reassessment

OBJECT

The aim of this study was to determine the prevalence of cerebral saccular aneurysms in patients with carotid artery and/or vertebral artery (VA) fibromuscular dysplasia (FMD).

METHODS

A metaanalysis was performed using data from 17 previously reported series of patients with internal carotid artery (ICA) and/or VA FMD that included information on the prevalence of cerebral aneurysms. In addition, the authors retrospectively evaluated their own series of 117 patients with ICA and/or VA FMD to determine the prevalence of cerebral aneurysms. The metaanalysis of the 17 earlier series, which included 498 patients, showed a 7.6 +/- 2.5% prevalence of incidental, asymptomatic aneurysms in patients with ICA and/or VA FMD. In the authors' series of patients with FMD, 6.3 +/- 4.9% of patients harbored an incidental, asymptomatic aneurysm. When the authors' series was combined with those included in the metaanalysis, the prevalence was found to be 7.3 +/- 2.2%. The prevalence of aneurysms in the general population would have to be greater than 5.6% for there to be no statistically significant difference (chi-square test, p < 0.05) when compared with this 7.3% prevalence in patients with FMD.

CONCLUSIONS

The prevalence of intracranial aneurysms in patients with cervical ICA and/or VA FMD is approximately 7%, which is not nearly as high as the 21 to 51% prevalence that has been previously reported.

Guglielmi detachable coil embolization for unruptured aneurysms in nonsurgical candidates: a cost-effectiveness exploration

PURPOSE

We calculated the incremental cost-utility ratio for Guglielmi detachable coil (GDC) embolization versus no therapy for unruptured intracranial aneurysms considered inappropriate for surgical clipping procedures.

METHODS

Decision tree and Markov analyses that employ cohort simulation were applied to determine the incremental cost-utility ratio of GDC embolization versus no therapy for unruptured cerebral aneurysms. Clinical values required as input data were estimated from the literature for the following variables: relative frequencies of complete aneurysmal occlusion, partial aneurysmal occlusion, and attempted coiling (no coils detached); morbidity and mortality of GDC embolization; frequency, morbidity, and mortality of spontaneous aneurysmal rupture in untreated and GDC-embolized aneurysms; annual rate of recanalization of GDC-embolized aneurysms; quality of life when knowingly living with untreated or GDG-embolized aneurysms and of living with fixed neurologic deficit; costs of GDC embolization, spontaneous aneurysmal rupture, stroke, and rehabilitation; and discount rate. Cost-utility ratios below $50000 per quality-adjusted life year saved were considered acceptable. Sensitivity analyses were performed for all relevant input variables.

RESULTS

Baseline input values resulted in acceptable cost-utility ratios for GDC embolization of unruptured intracranial aneurysms. These ratios remained within acceptable limits across wide ranges of various input parameters. Cost-effectiveness was markedly affected by the natural course of unruptured, untreated aneurysms; rates of spontaneous rupture greater than 2% per year resulted in favorable cost-utility ratios that were relatively unaffected by variation in GDC efficacy, while rates of rupture less than 1% per year resulted in unfavorable ratios that were highly dependent on GDC efficacy. Many of the GDC efficacy indexes, such as rate of failed coiling, early recanalization, and progressive aneurysmal thrombosis, have mild effects on the cost-utility ratios. GDC complication rate as well as life expectancy had moderate effects on the analysis. The influence of late aneurysmal recanalization was mild unless high rates of rupture for partially coiled aneurysms were applied. Suboptimal clip placement resulting from the presence of GDC coils within a ruptured aneurysm had no demonstrable consequence on cost-utility ratios.

CONCLUSIONS

The single most influential variable determining the cost-effectiveness of GDC embolization in our analysis was the natural course of untreated aneurysms. Other important variables included GDC-related morbidity and life expectancy at the time of GDC embolization.

In vitro proliferation and adhesion of basic fibroblast growth factor-producing fibroblasts on platinum coils

PURPOSE

To evaluate the growth and adhesion characteristics in vitro of genetically modified, basic fibroblast growth factor-producing fibroblasts on platinum detachable coils.

MATERIALS AND METHODS

Coils of two sizes were coated with laminin, poly-L-lysine, fibronectin, and type I and type IV collagen and were cultured with basic fibroblast growth factor-secreting fibroblasts. Type I collagen strands were inserted in the lumen of some coils. Cellular proliferation and adherence during passage of coils through microcatheters were studied with both light and scanning electron microscopy. Growth factor concentration in the culture medium was measured.

RESULTS

Rapid cellular proliferation was noted on all coated coils except those coated with type IV collagen. Proliferation on uncoated coils was slightly slower than on most coated coils, although confluent cell layers were present on uncoated larger-diameter coils within 48 hours. Cells had a marked propensity to grow between the primary coil windings into the coil lumen, except in coils that contained collagen filaments. Passage through microcatheters caused widespread stripping of cells from the outer surface of coils, especially the uncoated samples. Viable cells remained in the coil lumen. Supernatant contained high concentrations of growth factor.

CONCLUSION

Platinum embolic coils are a promising mechanism of cell delivery for stimulation of scar formation or other desirable biologic effects.

Percutaneous transvenous coil embolization of a type 4 sagittal sinus dural arteriovenous fistula: case report

OBJECTIVE AND IMPORTANCE

To present an alternative endovascular therapy for a Type 4 sagittal sinus dural arteriovenous fistula (DAVF).

CLINICAL PRESENTATION

A 74-year-old man presented with right facial paresthesias. Magnetic resonance imaging revealed an enlarged left parasagittal cortical vein adjacent to the superior sagittal sinus. Angiography demonstrated a Type 4 sagittal sinus DAVF.

INTERVENTION

The DAVF was cured using percutaneous transvenous coil embolization.

CONCLUSION

This case represents the first report in which a sagittal sinus DAVF was cured using a percutaneous transvenous endovascular approach.

Typical and atypical MR imaging features of intracranial epidermoid tumors

OBJECTIVE

We categorized the MR imaging characteristics of intracranial epidermoid tumors.

MATERIALS AND METHODS

MR images from 23 cases of intracranial epidermoid tumors were reviewed retrospectively. Signal intensities of tumor relative to surrounding structures were noted, as were the internal architecture of the tumors and the presence and degree of hydrocephalus.

RESULTS

Seventeen (74%) of 23 cases of intracranial epidermoid tumors were revealed as slightly hyperintense relative to CSF on T1-weighted MR images. Nineteen (95%) of 20 cases were hyperintense relative to CSF on proton density-weighted MR images. Fifteen (65%) of 23 cases were isointense to CSF on T2-weighted MR images, whereas the remaining eight cases (35%) were hyperintense to CSF on T2-weighted MR images. One (4%) of 23 cases showed signal intensity that was isointense to CSF on all pulse sequences. Fifteen (65%) of 23 cases showed heterogeneous signal characteristics on either T1-weighted or proton density-weighted MR images, or both. Eight (35%) of 23 cases showed a rim of hyperintensity on proton density-weighted MR images. Five (33%) of the 15 cases that received gadolinium showed rim enhancement. Five (22%) of 23 cases were multilocular, with different regions of tumors showing highly variable imaging characteristics. Two (9%) of 23 cases showed high signal intensity on T2-weighted MR images in the adjacent brain parenchyma. Two (9%) of 23 cases showed mild hydrocephalus. Six (43%) of 14 tumors that either originated in or secondarily involved the cerebellopontine angle also extended into the ipsilateral Meckel's cave.

CONCLUSION

On T1-, proton density-, and T2-weighted MR images intracranial epidermoid tumors usually showed heterogeneous signal intensity that was hyperintense to CSF. On all spin-echo pulse sequences epidermoid tumors with signal characteristics isointense to CSF were unusual. Hydrocephalus, even in the setting of marked displacement and compression of the brainstem, was not usually seen on MR imaging. Meckel's cave was often involved secondarily with epidermoid tumors that involved the cerebellopontine angle.

Posterior fossa hemorrhage after supratentorial surgery

PURPOSE

To evaluate the imaging findings, possible pathogenesis, and frequency of hemorrhage near the tentorial surface of the cerebellum after supratentorial surgery.

METHODS

Over a 5-year period, 13 patients with posterior fossa hemorrhage after supratentorial surgery were identified with postoperative CT studies, which were obtained in all patients after craniotomy. Four of the 13 patients also had postoperative MR examinations. Preoperative and postoperative radiologic studies and medical records were reviewed.

RESULTS

All hemorrhages were located along the superior aspect of the cerebellum transversely oriented along the cerebellar fossa and fissures. None of the patients had coagulopathy or radiologic evidence of posterior fossa tumor or vascular malformation. None of the hemorrhages had an appearance typical of hypertensive hemorrhage. Ten patients (77%) had lumbar drains placed before surgery and all had epidural drains placed at the conclusion of surgery. One patient had surgery for a meningioma, and 12 had surgery for aneurysms. The frequency of hemorrhage after aneurysmal surgery was 3.5%. No neurologic deficits developed referable to the cerebellum.

CONCLUSIONS

Hemorrhage should be viewed as a potentially benign sequela of surgery rather than as an indication of hypertension, aneurysm, or previously unrecognized vascular malformation or neoplasm.

Thrombogenicity of hydrophilic and nonhydrophilic microcatheters and guiding catheters

PURPOSE

To assess in a swine model the in vivo thrombogenicity of various microcatheters and guiding catheters as a function of catheter material, catheter coating, and duration of implantation.

METHODS

Microcatheters (Tracker 18 and Fastracker 18, Target Therapeutics, Fremont, Calif; Magic 1.8, Balt, Montmorency, France; and Transit, Cordis Endovascular Systems, Miami Lakes, Fla) were placed through 6F guiding catheters (Fasguide, Target Therapeutics, and Envoy, Cordis Endovascular Systems) into the common carotid arteries of swine for 30 minutes (short term), 90 minutes (medium term), and 35 days (long term). Guiding catheters were implanted for 5 hours. At the end of the implantation periods the catheters were retracted and fixed for scanning electron microscopy.

RESULTS

The surface of the Fastracker microcatheter was devoid of debris after both short- and medium-term implantation. The Tracker microcatheter had minimal accumulation of cellular elements whereas the Transit microcatheter showed moderate accumulation of nondeformed red blood cells. Neither the Tracker nor the Transit microcatheter showed evidence of increasing debris accumulation after medium-term implantation as compared with short-term implantation. The Magic microcatheter was coated with gross thrombus after both short- and medium-term implantation. The Fasguide guiding catheter was nearly devoid of debris, while the Envoy guiding catheter had moderate thrombus formation. Long-term implantation of the Fastracker microcatheter was well tolerated whereas that of the Transit catheter resulted in vessel occlusion.

CONCLUSIONS

Hydrophilic microcatheters and guiding catheters are less thrombogenic than their nonhydrophilic counterparts, but not all hydrophilic coatings are equally hypothrombogenic. Degree of thrombogenicity depends on catheter material rather than surface morphology. Medium-term implantation did not yield increasing thrombus formation relative to short-term implantation.

Serotonergic innervation of the supraependymal neuronal complex of the golden hamster

A ganglion-like system of intraventricular neuronal perikarya and processes known as the supraependymal neuronal complex (SENC) is located on the floor of the third ventricle of the golden hamster. Serotonergic neuronal elements were identified in the SENC by immunocytochemical techniques. Serotonin (5-hydroxytryptamine, 5-HT) was not detected within supraependymal neuronal perikarya. However, serotonergic nerve fibers were found to project via the median eminence both onto the surface and into the neuropil of the SENC. The SENC is thought to be involved in neuroendocrine regulation since it innervates the pituitary gland. The results of the present study suggest that serotonin plays a role in SENC/pituitary gland interaction.

Percutaneous transvenous coil embolization of a Djindjian type 4 tentorial dural arteriovenous malformation

We report a 60-year-old man who had a progressive neurologic deficit resulting from a Djindjian type 4 tentorial dural arteriovenous malformation (DAVM). The DAVM was repaired via percutaneous transvenous coil embolization.

Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral body compression fractures: technical aspects

PURPOSE

To describe a technique for percutaneous vertebroplasty of osteoporotic vertebral body compression fractures and to report early results of its use.

METHODS

The technique was used over a 3-year period in 29 patients with 47 painful vertebral fractures. The technique involves percutaneous puncture of the involved vertebra(e) via a transpedicular approach followed by injection of polymethylmethacrylate (PMMA) into the vertebral body.

RESULTS

The procedure was technically successful in all patients, with an average injection amount of 7.1 mL PMMA per vertebral body. Two patients sustained single, nondisplaced rib fractures during the procedure; otherwise, no clinically significant complications were noted. Twenty-six patients (90%) reported significant pain relief immediately after treatment.

CONCLUSION

Vertebroplasty is a valuable tool in the treatment of painful osteoporotic vertebral fractures, providing acute pain relief and early mobilization in appropriate patients.

Ruptured vertebrobasilar aneurysms: frequency of the nonaneurysmal perimesencephalic pattern of hemorrhage on CT scans

PURPOSE

To determine the frequency of the computed tomographic (CT) pattern of nonaneurysmal perimesencephalic subarachnoid hemorrhage in the setting of ruptured posterior fossa aneurysms.

MATERIALS AND METHODS

Four neuroradiologists independently and retrospectively reviewed cranial CT scans of 169 patients with ruptured vertebrobasilar aneurysms (44 cases of posteroinferior cerebellar artery aneurysm, 20 cases of superior cerebellar artery aneurysm, and 105 cases of basilar-tip aneurysm).

RESULTS

The mean frequency of nonaneurysmal perimesencephalic pattern of subarachnoid hemorrhage in ruptured vertebrobasilar aneurysms was 7.1% (48 of 676 readings) among the four readers. The mean frequency of aneurysms with the pattern of hemorrhage for each location was as follows: basilar tip, 9.8% (41 of 420 readings); superior cerebellar artery, 5.0% (four of 80 readings); and posteroinferior cerebellar artery, 0%. In 75% (six of eight) of the cases in which the CT pattern of hemorrhage was deemed compatible by all readers with nonaneurysmal hemorrhage, the clinical presentation was mild.

CONCLUSION

Because ruptured posterior fossa aneurysms manifest with the nonaneurysmal pattern of hemorrhage in approximately 10% of cases, a high degree of suspicion should be maintained even if the pattern of subarachnoid hemorrhage suggests a nonaneurysmal origin and clinical symptoms are mild.

3D gadolinium-enhanced MR angiography of the carotid arteries

PURPOSE

To compare gadolinium-enhanced magnetic resonance angiography (MRA) of the carotid bifurcation with 2D time-of-flight (TOF) MR angiography with regard to image quality and duration of examination.

MATERIALS AND METHODS

Gadolinium contrast was administered intravenously during 3D MR imaging at 1.5 Tesla in 46 patients presenting with suspected carotid occlusive disease. 2D time-of-flight MR angiography of the carotid bifurcation had been performed in each patient prior to gadolinium-enhanced MR angiography.

RESULTS

Gadolinium MRA eliminated slice misregistration and in-plane saturation artifacts that occasionally degrades 2D TOF MR angiography. Gadolinium MRA required less than 4 min to image from the aortic arch to the skull base compared to 11 min for 2D TOF with comparable signal-to-noise ratio (SNR). Postprocessing was required to eliminate overlapping venous enhancement. Both techniques had susceptibility related artifactual loss of signal at the skull base and both demonstrated a linear artifact paralleling the long axis of arteries.

CONCLUSION

Gadolinium-enhanced MR angiography is a promising technique for the evaluation of patients with carotid occlusive disease because it rapidly images the carotid arteries from the aortic arch to the skull base and eliminates some of the artifacts that degrade 2D TOF MR angiography.

Primary osseous amyloidoma causing spinal cord compression

The myelographic, CT, and MR findings of a rare localized primary bone amyloidoma causing upper thoracic spinal cord compression are presented. Imaging showed a large, calcified mass centered in the posteromedial portion of the left second rib that invaded the second thoracic vertebra and the spinal canal.

Immunocytochemical detection of oxytocin in the supraependymal neuronal complex of the golden hamster

A system of intraventricular neuronal perikarya and processes known as the supraependymal neuronal complex (SENC) is located on the floor of the third ventricle and innervates the neurohypophysis of the golden hamster (Mesocricetus auratus). Immunocytochemical techniques were used to determine if oxytocin and/or vasopressin are present in the neuronal elements of the SENC. Oxytocinergic fibers were observed to breach the ependyma of the median eminence and enter the neuropil of the SENC. Some of these fibers traverse the SENC to reach the adjacent ependymal surface and terminate on the floor of the third ventricle while others terminate within the neuropil of the SENC. These oxytocinergic fibers may be involved in the secretion of oxytocin into the cerebrospinal fluid (CSF). Vasopressinergic fibers were detected in the neuropil of the SENC in only one of four specimens examined and are assumed to be aberrant processes from the hypothalamo-neurohypophysial tract. Neither oxytocin nor vasopressin were detected in the neurons intrinsic to the SENC. The function of the SENC is unknown, but it may be involved in regulatory processes in which CSF oxytocin has been implicated, such as osmotic homeostasis and/or cardiovascular reflexes.

Elevated adenosine deaminase activity and hereditary hemolytic anemia. Evidence for abnormal translational control of protein synthesis

We have investigated the molecular basis of the marked elevation in erythrocyte adenosine deaminase (ADA) activity in a kindred with hereditary hemolytic anemia. Red cell ADA-specific activity was verified to be 70- to 100-fold normal levels. Western blots demonstrated a corresponding increase in erythrocyte ADA-specific immunoreactive protein. Analysis of genomic DNA revealed no evidence for amplification or major structural changes in the ADA gene. ADA-specific messenger RNA (mRNA) from proband reticulocytes was comparable in size and amount to mRNA from control reticulocytes. Translation of proband poly A+ reticulocyte mRNA in a rabbit reticulocyte lysate system and immunoprecipitation of 35S-labeled protein products with anti-ADA antibody yielded a band of approximately 42,000 apparent mol wt that was absent in translation products from control reticulocyte mRNAs. These data suggest that the increased ADA activity in red cells in this disorder results from the increased translation of an aberrant ADA mRNA.