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Purpose: Monitoring of blood pressure (BP) during procedures is variable, depending on multiple factors. Common methods include sphygmomanometer (BP cuff), separate radial artery catheterization, and side port monitoring of an indwelling sheath. Each means of monitoring has disadvantages, including time consumption, added risk, and signal dampening due to multiple factors. We sought an alternative approach to monitoring during procedures in the catheterization laboratory., Methods: A new technology involving a 330 µm fiberoptic sensor embedded in the wall of a sheath structure was tested against both radial artery catheter and sphygmomanometer readings obtained simultaneous with readings recorded from the pressure sensing system (PSS). Correlations and Bland-Altman analysis were used to determine whether use of the PSS could substitute for these standard techniques., Results: The results indicated highly significant correlations in systolic, diastolic, and mean arterial pressures (MAP) when compared against radial artery catheterization (p<0.0001), and MAP means differed by <4%. Bland-Altman analysis of the data suggested that the sheath measurements can replace a separate radial artery catheter. While less striking, significant correlations were seen when PSS readings were compared against BP cuff readings., Conclusions: The PSS has competitive functionality to that seen with a dedicated radial artery catheter for BP monitoring and is available immediately on sheath insertion without the added risk of radial catheterization. The sensor is structurally separated from the primary sheath lumen and readings are unaffected by device introduction through the primary lumen. Time delays and potential complications from radial artery catheterization are avoided., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Endovascular coil embolization has become an accepted and often first-line treatment for ruptured and unruptured intracranial aneurysms. While the complications of endovascular therapy of intracranial aneurysms have been well vetted in the literature, there are few reports solely concerning the complications and salvage techniques related to either the technical aspects of coil deployment or to the devices themselves. In this review the structural details of commonly used endovascular coils, technical complications related to coiling and salvage techniques used when these complications occur are discussed.

Background and Purpose: Hypothermia has been shown to be beneficial in the setting of acute SCI. However, widespread use has been hindered by the need for systemic hypothermia as the vehicle for achieving spinal cord hypothermia. This study demonstrates that localized spinal cord hypothermia can be achieved via a percutaneous approach while maintaining systemic normothermia., Materials and Methods: Five Yucatan swine underwent catheterization of the subarachnoid space and infusion of room temperature, chilled, and iced PL solutions into the cervical spinal canal, with drainage from the lumbar canal. Thermocouples were placed within the spinal cord and in the subarachnoid space and recorded during infusions and recovery from hypothermia., Results: Results demonstrated that hypothermia as low as 16.8°C is feasible in the spinal cord with retention of systemic normothermia, with strong (r = 0.95) correlation between the spinal cord temperature and the CSF temperature. Degrees of cooling varied with flow rates and with infusate temperature., Conclusions: While the data are preliminary in a small group of animals, the ability to rapidly create a wide range of controlled spinal cord hypothermia while preserving normal body temperature warrants wider exploration. The study also indicates that further investigation of the hypothesis that CSF temperature monitoring may be an acceptable surrogate for direct spinal cord temperature monitoring should be pursued.

Object: Postprocedural rebleeding is a significant source of morbidity following endovascular treatment of ruptured intracranial aneurysms. Previous large-scale reports include the Cerebral Aneurysm Rerupture After Treatment trial, the International Subarachnoid Aneurysm Trial, and the study on Early Rebleeding after Coiling of Ruptured Cerebral Aneurysms, which reported nonprocedural rebleeding rates within 30 days of treatment of 2.7%, 1.9%, and 1.4%, respectively. However, coiling of intracranial aneurysms is in a state of continual change due to advancing device design and evolving techniques. These studies included only patients initially treated prior to 2004. In the present study the authors assess the most recent short-term results with endovascular treatment of ruptured aneurysms., Methods: A multicenter retrospective chart review was conducted of patients undergoing endovascular treatment for ruptured intracranial aneurysms between July 2004 and October 2009. The technique used, including the use of stent or balloon assistance, was evaluated. Demographic and clinical factors, such as sex, age, initial clinical presentation, aneurysm size, aneurysm location, and modified Raymond Classification following initial treatment, were also evaluated and compared between the groups in which rebleeding did and did not occur., Results: A total of 469 patients underwent endovascular treatment for a ruptured aneurysm; nonprocedural rehemorrhage occurred within 30 days of the initial coiling in 4 cases (0.9%). Two patients (50%) died after rehemorrhage. Stent-assisted coiling was used during the original treatment in 1 (25%) of the 4 patients with a rerupture. However, no technical, clinical, or demographic factors were found to be statistically significant in association with rebleeding., Conclusions: Recent data suggest that the periprocedural rebleeding rate may be improving over time.

Cerebral sinus thrombosis, although uncommon, can be lethal if not recognized and treated quickly. Systemic heparin has become the treatment standard of care; however, some patients' conditions continue to deteriorate even while taking heparin. Endovascular techniques for thrombolysis have continued to evolve. The authors present a case of cerebral sinus thrombosis treated with a combination of mechanical and chemical intrasinus thrombolysis.

The statistics for stroke in the USA reads like a familiar ad slogan cited in most papers pertaining to acute ischemic stroke (AIS). Stroke is the third leading cause of death in the USA. While stroke ranks third among all causes of death, behind diseases of the heart and cancer, it is the leading cause of serious long-term disability in the USA.(1) Approximately 795 000 people, 87% of whom are ischemic, suffer from stroke each year in the USA.(2) That means that on average, every 40 seconds someone within the USA develops a stroke. For 2009 the combined direct and indirect cost of stroke, from hospitalization and rehabilitation to institutionalization, is estimated at $68.9 billion within the USA.(2).

Background and Purpose: Preoperative embolization facilitates the surgical management of complex cerebral arteriovenous malformations (cAVMs). This analysis aims to investigate the risks for preoperative cAVM embolization with Onyx., Materials and Methods: We retrospectively analyzed clinical data of all patients who underwent embolization with Onyx as a preoperative treatment of cAVMs at our institution since 2005 (US Food and Drug Administration [FDA] approval). Patients with arteriovenous fistulas were excluded. A total of 107 patients were treated for cAVMs during the study period. Of those patients, 41 underwent cAVM embolizations with Onyx in 82 procedures., Results: After the embolization, the cAVM diameter was reduced from 3.71 +/- 1.55 cm to 3.06 +/- 1.89 cm (P < .05). Median volume reduction was 75%. Complete occlusion with embolization alone was achieved in 4 (10%) cAVMs. The recurrence rate for completely occluded cAVMs was 50% (2 patients). A total of 71% of the 41 patients treated with Onyx underwent surgery, and 15% underwent radiosurgery. There were 9% who have not yet received definitive treatment of their residual cAVMs. A new permanent neurologic deficit occurred in 5 patients (6.1% per procedure or 12.2% per patient)., Conclusions: A considerable risk for a permanent neurologic deficit remains for cAVM embolization with Onyx. The risk has to be carefully weighted against the benefit of volume reduction in the treatment of cAVMs.

Background: Treatment of VLGUIA remains a challenge. To reduce mass effect and achieve complete occlusion, open surgery has been our favored treatment. However, endovascular therapy is preferred for lesions in the cavernous sinus or for older patients with complicating medical problems. The goal of this study is to investigate outcome of stent and/or coil treatment of VLGUIA., Methods: Beginning in 2002, the neuroform stent has been available to the University of Texas Southwestern Medical Center in Dallas. Since then until 2006, 15 patients were treated for VLGUIA with stenting and/or coiling at this institution. These 15 patients were used for a retrospective analysis in this study., Results: Median patient age was 65 years, median aneurysm size was 27 mm (20-37 mm), and median follow-up time was 22 months. Eight aneurysms were localized in the cavernous sinus and 7 at the ophthalmic segment of the internal carotid artery. Four aneurysms were completely occluded (100%); 3 aneurysms, nearly complete (90%-99%); and 8 aneurysms, partial (<90% occlusion). Twelve patients required retreatment. Final GOS was 1 (good recovery) in 11 patients, 2 (moderate disability) in 3 patients, and 3 (severely disabled) in 1 patient. No patient died or deteriorated., Conclusions: Stent/coil management of VLGUIA is constantly evolving. Current treatment results are promising, with very low morbidity/mortality. Disadvantage is the frequent persistence of residual aneurysm.

Objective: A classification system developed to characterize in-stent restenosis (ISR) after coronary percutaneous transluminal angioplasty with stenting was modified and applied to describe the appearance and distribution of ISR occurring after Wingspan (Boston Scientific, Fremont, CA) intracranial percutaneous transluminal angioplasty with stenting., Methods: A prospective, intention-to-treat, multicenter registry of Wingspan treatment for symptomatic intracranial atherosclerotic disease was maintained. Clinical and angiographic follow-up results were recorded. ISR was defined as greater than 50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent(s) and greater than 20% absolute luminal loss. ISR lesions were classified by angiographic pattern, location, and severity in comparison with the original lesion treated., Results: Imaging follow-up (3-15.5 months) was available for 127 intracranial stenotic lesions treated with Wingspan percutaneous transluminal angioplasty with stenting. Forty-one lesions (32.3%) developed either ISR (n = 36 [28.3%]) or complete stent occlusion (n = 5 [3.9%]) after treatment. When restenotic lesions were characterized using the modified classification system, 25 of 41 (61.0%) were focal lesions involving less than 50% of the length of the stented segment: three were Type IA (focal stenosis involving one end of the stent), 21 were Type IB (focal intrastent stenosis involving a segment completely contained within the stent), and one was Type IC (multiple noncontiguous focal stenoses). Eleven lesions (26.8%) demonstrated diffuse stenosis (>50% of the length of the stented segment): nine were Type II with diffuse intrastent stenosis (completely contained within the stent) and two were Type III with proliferative ISR (extending beyond the stented segment). Five stents were completely occluded at follow-up (Type IV). Of the 36 ISR lesions, 16 were less severe or no worse than the original lesion with respect to severity of stenosis or length of the segment involved; 20 lesions were more severe than the original lesion with respect to the segment length involved (n = 5), actual stenosis severity (n = 6), or both (n = 9). Nine of 10 supraclinoid internal carotid artery ISR lesions and nine of 13 middle cerebral artery ISR lesions were more severe than the original lesion., Conclusion: Wingspan ISR typically occurs as a focal lesion. In more than half of ISR cases, the ISR lesion was more extensive than the original lesion treated in terms of lesion length or stenosis severity. Supraclinoid internal carotid artery and middle cerebral artery lesions have a propensity to develop more severe posttreatment stenosis.

Background and Purpose: Wingspan is a self-expanding, microcatheter-delivered microstent specifically designed for the treatment of symptomatic intracranial atherosclerotic disease. Our aim was to discuss the effect of patient age and lesion location on in-stent restenosis (ISR) rates after percutaneous transluminal angioplasty and stenting (PTAS) with the Wingspan system., Materials and Methods: Clinical and angiographic follow-up results were recorded for all patients from 5 participating institutions. ISR was defined as >50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent and >20% absolute luminal loss. For the present analysis, patients were stratified into younger (55 years) age groups., Results: ISR occurred at a rate of 45.2% (14/31) in the younger group and 24.2% (15/62) in the older group (odds ratio, 2.6; 95% confidence interval, 1.03-6.5). In the younger group, ISR occurred after treatment of 13/26 (50%) anterior circulation lesions versus only 1/5 (20%) posterior circulation lesions. In the older group, ISR occurred in 9/29 (31.0%) anterior circulation lesions and 6/33 (18.2%) posterior circulation lesions. In young patients, internal carotid artery lesions (10/17 treated, 58.8%), especially those involving the supraclinoid segment (8/9, 88.9%), were very prone to ISR. When patients of all ages were considered, supraclinoid segment lesions had much higher rates of both ISR (66.6% versus 24.4%) and symptomatic ISR (40% versus 3.9%) in comparison with all other locations., Conclusion: Post-Wingspan ISR is more common in younger patients. This increased risk can be accounted for by a high prevalence of anterior circulation lesions in this population, specifically those affecting the supraclinoid segment, which are much more prone to ISR and symptomatic ISR than all other lesions.

Background: Lymphangiohemangioma, also called lymphatic-venous or venolymphatic malformation, is a rare malformation of the lymphatics, with vascular elements. These are low-flow vascular lesions., Objective: To evaluate the feasibility and efficacy of endoscopic injection sclerotherapy with doxycycline for low-flow vascular malformations in the GI tract., Design: Case report., Setting: Academic center., Patients: An adult man with lymphangiohemangioma that involved the mediastinum and the esophagus. The esophageal involvement caused dysphagia and chest pain., Interventions: We characterized the lesion with EUS and successfully treated the esophageal and paraesophageal lesions with endoscopic injection sclerotherapy by using doxycycline., Main Outcome Measurement: Symptom resolution and complications., Results: The patient's esophageal symptoms resolved with sclerotherapy. This is the first reported case of lymphangiohemangioma with esophageal involvement and the first reported case of endoscopic injection sclerotherapy by using doxycycline in the GI tract., Limitations: Case report and short follow-up period., Conclusions: Endoscopic injection sclerotherapy with doxycycline for lymphatic and low-flow vascular malformations in the GI tract is feasible, easy, safe, and effective.

The goals of this study were to evaluate brain activation in patients with probable Alzheimer's disease (AD), mild cognitive impairment (MCI), and controls while performing a working memory (WM) task. Eleven AD patients, ten MCI subjects, and nine controls underwent functional magnetic resonance imaging (fMRI) while performing a visual WM task. Statistical parametric maps of brain activation were obtained in each group, and group activation difference maps were generated. Ability to perform the task did not differ among the groups. Activation was observed in the parahippocampal region, superior-middle-inferior frontal gyri, parietal region, anterior-posterior cingulate, fusiform gyrus, and basal ganglia. MCI and AD groups showed more activation than the controls in the right superior frontal gyrus, bilateral middle temporal, middle frontal, anterior cingulate, and fusiform gyri. Activation in the right parahippocampal gyrus, left inferior frontal gyrus, bilateral cingulate and lingual gyri, right lentiform nucleus, right fusiform gyrus, and left supramarginal gyrus in the AD group was less than in the MCI group. The WM task evoked activation in widely distributed regions, consistent with previous fMRI studies. AD and MCI patients showed an increased extent of activation and recruitment of additional areas.

A percutaneous technique for visualizing sacral nerve roots is described. A fiberscope was inserted into the subarachnoid space through a sheath that was inserted via a percutaneous lumbar puncture. The sacral nerve roots were identified with endoscopic visualization and x-ray fluoroscopy localization of the endoscope. These images were compared with those obtained from a videoscope, which revealed better imaging. Specific sacral nerve roots can be identified by using a combination of endoscopy and x-ray fluoroscopy. This technique may enable minimally invasive interventions such as lysis of adhesions, arachnoid cyst decompression, selective dorsal rhizotomy, and more selective and precise nerve stimulation electrode placement.

Object: The purpose of this paper was to demonstrate the usefulness of various fiberoptic endoscopes for percutaneous intraspinal navigation of the spinal canal, posterior fossa, and ventricular system., Methods: Fresh, unembalmed cadavers were used, in which lumbar punctures were made for access to the subarachnoid space (in the case of larger [3.8- and 5-mm-diameter] endoscopes, small laminotomies were performed). Static and video images of pertinent structures were acquired for comparison among devices. Endoscopes were compared for their maneuverability, durability, field of view, and image quality. Seven sizes and types of endoscopes were considered. Overall, the devices offering a tip-deflecting mechanism were superior in maneuverability. Endoscopes in which a charged couple display chip was used at the tip of the scope for image acquisition offered improved image quality and field of view. Larger scopes, although more durable, were more rigid and may be limited in application. Multiple images from multiple devices are presented., Conclusions: Percutaneous intraspinal navigation offers a promising neurosurgical approach to the spinal canal, the posterior fossa, and the ventricular system. Concerns regarding safety, management of complications, and the lack of adjunctive tools for intervention through the endoscopes or for use under fluoroscopic guidance represent areas that warrant further investigation and development.

Background and Purpose: Our previous model of spinal cord injury (SCI) included six dogs undergoing 30-minute compression with a balloon in the subarachnoid space. We determined whether various balloon sizes and compression times creates a gradation of injuries., Methods: In 17 dogs (including our original six), angioplasty balloons 2, 4, or 7 mm in diameter (2 cm long) were inflated at T6 for 30, 120, or 240 minutes. T1- and T2-weighted, gadolinium-enhanced, and short-tau inversion recovery (STIR) MR images were obtained at 1.5 T. Spinal canal occlusion (SCO) was measured as balloon area-spinal cord area. Hematoxylin-eosin and beta amyloid precursor protein staining were performed to demonstrate hemorrhage and axonal injury, respectively. Injuries were scored as mild, moderate, or severe. Trends were assessed with one-way analysis of variance., Results: SCO was 12.5-20% for 2-mm balloons, 28-56% for 4 mm, and 62-82% for 7 mm. No abnormalities were seen with SCO <30%. T1- and T2-weighted images had the poorest diagnostic performance; STIR images were best for predicting hemorrhage and axonal injury. Hemorrhage was demonstrated more frequently than was axonal injury. SCO (P < .0001) and hemorrhage (P = .002) significantly increased with balloon size. Longer inflation times tended to increase injuries for a given size, but differences were not significant., Conclusion: Compression injuries depended on the level of SCO. The compression times tested had less effect than the degree of compression. The value of 1.5-T MR imaging varied with the sequence and improved with contrast enhancement. STIR images showed SCIs not otherwise detected.

Object: Preoperative embolization is viewed by the authors as a useful adjunct in the surgical management of cerebral arteriovenous malformations (AVMs). This study was performed to determine the rate of significant complication in patients undergoing this procedure., Methods: Demographic, anatomical, and procedure data were collected prospectively. The treating physician reported complications. In addition, a review of medical records including procedure reports, operative reports, and discharge summaries was performed. Univariate statistical analysis was performed to determine if any of the variables was predictive of a poor outcome of embolization (death or permanent neurological deficit). Endovascular procedures for embolization were performed 339 times in 201 patients during an 11-year period. Female patients comprised 53.7% of the study group and 85.6% of the AVMs were supratentorial. Embolization was performed using polyvinyl alcohol particles, N-butyl cyanoacrylate, detachable coils, and/or the liquid polymer Onyx. Analyzed by procedure, a poor result of embolization occurred in 7.7%. Analyzed by patient, 11% died or had a permanent neurological deficit as a result of the embolization. None of the demographic, anatomical, or procedure variables identified were predictive of a poor outcome., Conclusions: Preoperative embolization may gradually reduce flow to an AVM, reduce intraoperative blood loss, and reduce operative time. The risks of this procedure, however, are not insignificant and must be considered in planning treatment for patients with AVMs.

Percutaneous intraspinal navigation (PIN) is a new minimally invasive approach to the subarachnoid space. Using conventional radiographic fluoroscopy, entrance is gained to the lumbar subarachnoid space, allowing navigation throughout the spinal canal. Using an antenna/guidewire introduced via PIN, we performed endospinal MR imaging of the thoracic spinal cord in a cadaver and canine subject. Comparison images were obtained with an optimal surface coil. PIN allows endospinal MR imaging of the spinal cord, providing significant signal-to-noise ratio gains over conventional imaging.

Object: A case-control analysis of patients with SAH was performed to compare risk factors and outcomes at 6 months posthemorrhage in patients with a very small aneurysm compared with those with a larger aneurysm., Methods: All patients with SAH who were treated between January 1998 and December 1999 were studied. A very small aneurysm was defined as "equal to or less than 5 mm in diameter." Clinical data and treatment summaries were maintained in an electronic database. The Glasgow Outcome Scale (GOS) score was determined by an independent registrar. One hundred twenty-seven patients were treated. A very small aneurysm was the cause of SAH in 42 patients (33%), whereas 85 (67%) had aneurysms larger than 5 mm (mean diameter 11 mm). There were no differences in demographic variables or medical comorbidities between the two groups. Thick SAH (Fisher Grade 3 or 4) was more common in patients with a very small aneurysm than in those with a larger aneurysm (p = 0.028). One hundred eight patients underwent microsurgery (85%), 15 underwent coil embolization (12%), and four (3%) required both procedures. Vasospasm occurred in nine patients (21%) with very small aneurysms compared with 14 (16%) with larger aneurysms (p = 0.62). Shunt-dependent hydrocephalus occurred in nine patients (21%) with very small aneurysms and in 19 (22%) with larger aneurysms (p = 1). The mean GOS score for both groups was 4 (moderately disabled) at 6 months., Conclusions: Small aneurysms produce thick SAH more often than larger aneurysms. There is no difference in outcome after SAH between patients with a very small aneurysm and those with a larger aneurysm.

Objectives: The aims of this study were to determine the feasibility of obtaining auditory cortex activation evoked by pure tones presented at threshold and suprathreshold hearing levels, to evaluate tonotopicity of the primary auditory cortex, and to determine the effect of stimulus intensity on auditory cortex activation using silent functional magnetic resonance imaging (fMRI)., Methods: Sixteen subjects with normal hearing underwent silent fMRI. An audiometer was used to deliver pure tones of 1000, 2000, and 4000 Hz to the left ear. Two levels of acoustic stimulation were used: 1). threshold, hearing level determined in the scanner room and 2). suprathreshold, 70 dB hearing loss (HL). Tonotopicity and stimulus intensity coding was assessed on the basis of the location, extent, and amount of the auditory cortex activation., Results: The localization of activation moved to more medial and posterior regions of the primary auditory cortex as the frequency of the pure tone increased. Compared with a threshold stimulus, a suprathreshold stimulus evoked the same regions with increased spatial extent. The average increase in the right auditory cortex activation in response to suprathreshold stimulus was 57% at 1000, 51% at 2000, and 45% at 4000 Hz compared with that activated by the threshold stimulus., Conclusions: Silent fMRI can be used to evaluate auditory cortex activation using low-intensity stimuli. The level of stimulus intensity increases the amount of auditory cortex activation and influences the fMRI mapping of the tonotopic organization of the primary auditory cortex.

Purpose: To evaluate auditory cortex activation evoked by pure-tone stimulus using silent functional magnetic resonance imaging (FMRI)., Material and Methods: Nine volunteers with normal hearing as determined with pure-tone audiometry were studied. Auditory cortex activation was evoked by pure-tone stimuli presented monaurally at 1,000, 2,000, and 4,000 Hz. Images of auditory cortex activation were obtained using silent and conventional FMRI techniques. Heschl's gyrus activation was evaluated by the number of voxels exceeding a predetermined significance level (P <.0001)., Results: In both techniques, all subjects showed activation in the Heschl's gyrus. Silent FMRI detected more activation in all studied frequencies compared with the conventional FMRI. The observed difference in the Heschl's gyrus activation between the techniques reached statistical significance for 1,000 Hz frequency (P <.05)., Conclusions: The amount of Heschl's gyrus activation detected with silent FMRI is greater than that of conventional FMRI. Silent FMRI technique can be used to acquire functional images of the auditory cortex without the confounding effects of scanner noise.

Object: The records of 30 patients with posterior cerebral artery (PCA) aneurysms treated during a 12-year period were reviewed to determine outcome and the risk of visual field deficit associated with PCA sacrifice., Methods: Clinical data and treatment summaries for all patients were maintained in an electronic database. The Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) scores were determined by an independent registrar. Visual field changes were determined by review of medical records. Twenty-eight patients were treated with open surgery, one of them after an attempt at detachable coil embolization failed. Two patients underwent successful endovascular PCA sacrifice. The mean GOS and mRS scores in 18 patients with unruptured aneurysms were 4 and 2, respectively, at discharge. Subarachnoid hemorrhage (SAH) from other aneurysms and neurological deficits caused by the PCA lesion or underlying disease contributed to poor outcomes in this group. The mean GOS and mRS scores in 12 patients with ruptured aneurysms were 4 and 4, respectively, at discharge. One patient died of severe vasospasm. Neurological deficits secondary to SAH and, in one patient, treatment of a concomitant arteriovenous malformation contributed to poor outcomes in the patients with ruptured aneurysms. Seven patients with normal visual function preoperatively underwent PCA occlusion. One patient (14%) developed a new visual field deficit., Conclusions: Optimal treatment of PCA aneurysms is performed via one of several surgical approaches or by endovascular therapy. The approach is determined, in part, by the anatomical location and size of the aneurysm and the presence of underlying disease and neurological deficits.

Percutaneous intraspinal navigation (PIN) is a new minimally invasive approach to the CNS. The authors studied the utility of MR-guided intracranial navigation following access to the subarachnoid compartment via PIN. The passive tracking technique was employed to visualize devices during intracranial navigation. Under steady-state free precession (SSFP) MR-guidance a microcatheter-microguidewire was successfully navigated to multiple brain foci in two cadavers. SSFP MR fluoroscopy possesses adequate contrast and temporal resolution to allow MR-guided intracranial navigation.

We describe a percutaneous approach for cerebral surgical access. After lumbar puncture, the spinal subarachnoid space was traversed by using standard angiographic guidewire techniques until the introducer catheters were in the intracranial space. Under fluoroscopic guidance, the intracranial subarachnoid space was navigated, and the ventricular system entered. Subarachnoid placement was confirmed with contrast-enhanced digital angiography. Placement anterior to the brain stem was confirmed in both cadavers during dissection, and spinal navigation without cord damage from the anterior or posterior approach was confirmed in one. Percutaneous intraspinal navigation is a new route of access for cerebrospinal surgery that has many potential applications.

Background and Purpose: Previous animal models for spinal cord injury required laminectomy and exposure of the spinal cord to create direct trauma, compromising imaging by both surgical artifact and the nature of the production of the injury. Our purpose was to study a model that uses percutaneous intraspinal navigation with an angioplasty balloon, providing a controlled degree of spinal cord compression and allowing improved MR imaging of spinal cord injury., Methods: Nine mongrel dogs were studied. MR images were obtained of six dogs after technique development in three dogs. Angioplasty balloons measuring 7 or 4 mm in diameter and 2 cm in length were placed in the midthoracic subarachnoid space. Imaging was performed by using a 1.5-T MR imaging unit before and after balloon inflation. The balloon was inflated within 5 seconds and deflated after 30 minutes. T1- and T2-weighted and contrast-enhanced images were acquired. Spinal cords were submitted for pathologic examination., Results: All four animals with 7-mm balloons experienced hemorrhage, and three had axonal injury revealed by histopathologic examination. One of two animals with 4-mm balloons experienced no injury, and one had axonal injury without hemorrhage. Regional parenchymal enhancement was seen in two of the animals with 7-mm balloons., Conclusion: This percutaneous spinal cord injury model results in a graduating degree of injury. It differs from previous techniques by avoiding surgical exposure and the associated artifacts, yet it offers histopathologic findings similar to those of human spinal cord injury. The canine spinal cord is amenable to MR imaging with clinical imaging units. Further evaluations with various durations of compression and various balloon sizes are warranted.

Summary: With the rapidly developing applications of GDC endovascular aneurysm embolization, the recognition and treatment of potential intra-procedural complications is crucial to reducing the morbidity and mortality of this procedure. Thromboembolic complications occur with an incidence of 2-11% with endovascular aneurysm coiling. We describe five cases in which the intraarterial use of thrombolytics was applied to disrupt a fresh clot and recanalize the occluded vessels with variable angiographic and clinical success. Five cases are presented in which thromboembolic complications occurred during or shortly after GDC endovascular aneurysm occlusion. The complication was recognized while depositing coils in two cases, on post-embolization angiogram in one, and a few hours following embolization in two cases in which a new neurologic deficit developed in the ICU. In those cases recognized while the microcatheter was near the aneurysm site, immediate thrombolysis was performed at the site of occlusion. The patients who developed a new neurologic deficit were returned to the endovascular suite and the site of occlusion was noted to be distal to the coiled aneurysm. Clot disruption was performed with the microcatheter before delivering intraarterial thrombolytics. Thromboembolic complications of GDC aneurysm embolization are fortunately rare and can be managed with delivery of thrombolytic therapy at the site of occlusion. Intraarterial thrombolysis of fresh clot caused by GDC aneurysm occlusion can successfully open the occluded vessels but not without serious risk of hemorrhage.

Beginning in the 1960s, neurosurgeons and radiologists have made attempts to treat intracranial aneurysms using nonclip techniques. The evolution of such therapy has included acrylics, metallic particles, balloons, electric current, and nondetachable and detachable coils. This article will chronologically review these various techniques and the papers that reported their results so that the reader can understand how endovascular therapy developed and the position it currently holds in the treatment of intracranial aneurysms.

Objective: In this study, the incidence, etiologies, and management with respect to clinical outcome of patients with iatrogenic aneurysmal rupture during attempted coil embolization of intracranial aneurysms are reviewed., Methods: A retrospective analysis was conducted of 274 patients with intracranial aneurysms treated with Guglielmi detachable coils over a 6-year period from 1994 to 2000. Patient medical records were examined for demographic data, aneurysm location, the number of coils deployed preceding and after aneurysmal rupture, the etiology of the rupture, and the clinical status on admission and at the time of discharge., Results: Of 274 patients with intracranial aneurysms treated with coil embolization, six (2%) had an intraprocedural rupture. Of these six, two were women and four were men. The mean age was 67 years (range, 52-85 yr). Mean follow-up time was 8 months (range, 0-25 mo). Aneurysmal rupture resulted from detachment of the last coil in three patients, detachment of the third coil (of four) in one patient, and insertion of the first coil in another patient. In one patient, the aneurysmal rupture was a result of catheter advancement before detachment of the last coil. The Glasgow Outcome Scale score at last follow-up examination was 1 in two patients, 2 in two patients, and 5 in two patients., Conclusion: The rate of rupture of aneurysms during coil embolization is approximately 2 to 4%. The clinical outcome may be related to the timing of the rupture and the number of coils placed before rupture. If extravasation of contrast agent is seen, which suggests intraprocedural rupture, further coil deposition should be attempted if safely possible.

Objective: Symptomatic vertebrobasilar artery stenosis portends a poor prognosis, even with medical therapy. Surgical intervention is associated with considerable morbidity, and percutaneous angioplasty alone has demonstrated mixed results, with significant complications. Recent advances in stent technology have allowed for a novel treatment of symptomatic, medically refractory, vertebrobasilar artery stenosis. We report on a series of patients with medically refractory, posterior circulation stenosis who were treated with transluminal angioplasty and stenting at two medical centers in the United States., Methods: A retrospective analysis of data for 11 consecutive patients with symptomatic, medically refractory, intracranial, vertebral or basilar artery stenosis was performed. All patients were treated with percutaneous transluminal angioplasty and stenting. Short-term clinical and angiographic follow-up data were obtained., Results: Among 11 patients who were treated with stent-assisted angioplasty of the basilar or vertebral arteries, there were three periprocedural deaths and one delayed death after a pontine stroke. Other complications included a second pontine infarction, with subsequent residual diplopia. The remaining seven patients (64%) experienced symptom resolution and have resumed their preprocedural activities of daily living. Angiographic follow-up examinations demonstrated good patency of the stented lesions for five of seven survivors (71%); one patient exhibited minimal intrastent intimal hyperplasia, and another patient developed new stenosis proximal to the stent and also developed an aneurysm within the stented portion of the basilar artery. The last patient exhibited 40% narrowing of the treated portion of the vessel lumen., Conclusion: Recent advances in stent technology allow negotiation of the proximal posterior circulation vasculature. Although the treatment of vertebrobasilar artery stenosis with angioplasty and stenting is promising, long-term angiographic and clinical follow-up monitoring of a larger patient population is needed.

In the mid-1960s, radiologists began experimenting with stents for use in the peripheral vasculature in the hope of treating vascular insufficiency resulting from vessel stenosis in a nonsurgical manner. The 1990s saw stents move into the neurovascular arena for the management of a variety of disease processes, including arterial and venous sinus stenosis, arterial dissection, arterial aneurysms, and arteriovenous fistulae. This article reviews the current status of stenting in regard to the management of neurovascular maladies.

Type 4 Ehlers-Danlos Syndrome (EDS 4) is the most malignant form of Ehlers-Danlos Syndrome, often accompanied by neurovasacular complications secondary to vessel dissection or aneurysms. The fragile nature of connective tissue in these patients makes exovascular and endovascular treatment hazardous. We have treated four patients with EDS 4 over the last 8 years by using neuroendovascular procedures. Two of these individuals suffered remote vascular injuries around the time of their procedures and ultimately died. The circumstances surrounding their deaths will make up the body of this report.

Background and Purpose: Intravascular stents are being used with increasing frequency in interventional neuroradiology. They provide the potential to expand the therapeutic capabilities of the endovascular therapist and stand to revolutionize endovascular intervention within both the intracranial and extracranial vessels. We present our application of stent technology to further the understanding of endovascular rescue from procedural complications and the solving of complex clinical problems., Methods: Three patients underwent unplanned placement of intravascular stents. In two patients a stent was used to provide stabilization of an irretrievable intravascular device; in the third patient a stent was used to provide a scaffolding for proximal external carotid sacrifice., Results: Stent deployment was successful in all patients. The intravascular devices stabilized by stent placement included unraveled fragments of a Guglielmi detachable coil (GDC) and a partially deployed coronary stent. Proximal external carotid sacrifice was achieved with the aid of a stent in one patient to control hemorrhage from recurrence of laryngeal cancer. No periprocedural neurologic complications were encountered. Six-month follow-up angiography in one patient showed only minimal myointimal hyperplasia induced by stent-stabilized GDC fragments adjacent to the internal carotid vessel wall., Conclusion: Stents can be used to provide stabilization of irretrievable intravascular devices or as a scaffolding for proximal vessel sacrifice. These applications may allow endovascular rescue of procedural complications and solve unique clinical problems.

Background and Purpose: Brain temperature may be an important factor governing the extent of neuronal injury associated with stroke. The goal of this study was to develop a noninvasive method for measuring brain temperature, both to characterize the extent to which temperature changes after stroke and to test protocols designed to reduce brain temperature. We used an animal model to test the ability of 1H MR spectroscopy to measure temperature from infarcted brain tissue at 24 hours after insult., Methods: Unilateral permanent focal ischemia in the middle cerebral artery territory was induced in adult dogs by intravascular delivery of microfibrillar collagen. MR imaging performed at 24 hours after insult was used to guide the implantation of temperature probes into the basal ganglia infarct and into the same anatomic location on the contralateral side. Serial non-water-suppressed 1H MR spectra were obtained from 1.3-cm3 voxels using an echo time of 136 and 272 ms, alternately, from the infarcted and contralateral non-infarcted tissue during a period when brain temperature was raised and lowered by whole-body heating and cooling., Results: The chemical shift difference between the 1H MR spectroscopy signal of water and N-acetylaspartate or water and trimethylamines was plotted against brain temperature for two voxel locations. The slope and intercept of the plots obtained for infarcted and non-infarcted brain were not significantly different (P < .05, t test), and there was no difference between the slope and intercept of plots made from data collected with an echo time of 136 or 272 ms., Conclusion: The results of this study indicate that brain temperature can be measured from regions of brain containing infarcted tissue, at least up to 24 hours after ischemia. It should be possible to apply the 1H MR spectroscopy method used in the present study to measure brain temperature after stroke.

Objective and Importance: Symptomatic basilar artery stenosis is a highly morbid disease process. Recent technological and pharmaceutical advances make endovascular treatment of this disease process possible., Clinical Presentation: We report three cases of patients with a symptomatic basilar artery stenosis despite anticoagulation., Intervention: All patients were successfully treated with a flexible coronary stent and perioperative antiplatelet medications without incident. Poststenting angiography demonstrated a normal-caliber artery with patent perforators. In one case, a poststenting cerebral blood flow study revealed improved perfusion., Conclusion: A new generation of stents and balloons makes access to intracranial intradural arterial pathological abnormalities possible. Such devices may well revolutionize the management of ischemic and hemorrhagic intracranial cerebrovascular disease.

Summary: We determined the types and rates of complications related to diagnostic angiography and neuroradiologic interventional procedures at a centre that carries out the full spectrum of angiographic procedures. The occurrence of immediate and delayed complications in 1929 neuroangiographic procedures (1358 diagnostic and 571 interventional) performed between the years 1993-1996 was prospectively identified and recorded on a daily basis. A retrospective review of all charts of patients having procedures conducted during the study period was also carried out to ensure that no complications were missed. The overall complication rate for diagnostic cerebral angiography was 2.2%. Puncture site complications ranged from 0 - 0.1 %. Vessel injury distal to the puncture site ranged from 0.2 - 0.6%. The temporary neurologic complication rate was 0.3%, while the permanent rate was 0.4%. There were no contrast reactions. The death rate was 0.1 %. Interventional procedures had higher incidences of complications with overall rates ranging from 5.3 - 33%. Temporary and permanent neurologic deficits occurred at a rate of 0 - 10.5% depending upon the procedure involved. Individual complication and death rates and complication categories are provided for arteriovenous malformation embolisation, tumour embolisation, temporary balloon occlusion tests, detachable balloon vessel sacrifice, urokinase infusion, angioplasty, papavarine infusion, GDC embolisation, and carotid cavernous fistula embolisation. When carried out in experienced hands, neuroangiography and neurointervention are relatively safe with low incidences of neurologic and non-neurologic complications. Knowledge of these rates is important when counselling patients prior to treatments or deciding upon the risk-benefit ratio of preoperative procedures.

With the growing use of endovascular therapy for intracranial aneurysms, it is important that we understand at a cellular level the processes that lead to lesion obliteration. We present autopsy findings, including electron and light microscopic studies, of a basilar artery aneurysm that was successfully embolized with the Guglielmi detachable coil system 4 weeks before the patient died.

Purpose: To determine whether transient ischemia can be separated from permanent ischemia via calcium 45 autoradiography and to assess the applicability of dual isotope single-photon emission CT (SPECT) in the evaluation of cerebral blood flow., Methods: We examined calcium influx in 12 dogs (group A) by using whole-brain calcium 45 autoradiography: Animals received 250 microCi/kg 24 hours after 30-minute (n = 6) or permanent (n = 6) middle cerebral artery (MCA) occlusion. Forty-eight hours after MCA occlusion, 5-mm coronal brain sections were fixed for either autoradiography or pathologic examination. In a separate study, 9 mongrel dogs (group B) were given 250 microCi/kg calcium 45 and a mean dose of 700 microCi/kg technetium Tc 99m hexamethylpropyleneamine oxime intravenously. A silicone plug was then injected into the internal carotid artery and angiography was performed to verify MCA occlusion. A 10th (control) animal did not undergo occlusion. In an 11th animal, placement of the plug could not be achieved and a slurry of microfibrillar collagen was injected into the carotid artery. No angiography was performed in animals 10 and 11. After occlusion, each animal was injected with a mean dose of 126 microCi/kg simultaneous acquisition for technetium 99m and 123I-iodoamphetamine., Results: In group A, all animals who had permanent MCA occlusion showed infarction and increased calcium 45 uptake in infarcted territories. None of the animals who had 30-minute occlusion had either increased calcium 45 uptake or infarction at 48 hours. In group B, 7 or 10 dogs had SPECT findings that were consistent with the calcium autoradiographic marker for ischemia. One animal died during the procedure and 1 dog served as a control., Conclusion: Calcium 45 autoradiography allowed distinction between areas of temporary and permanent occlusion. Iodoamphetamine imaging was not consistently sensitive to that level of ischemia. Timing of calcium influx may lead to insight that could impact timing of pharmacologic or endovascular intervention.

Few cases of radiation injury related to lengthy interventional neuroradiologic procedures have been reported, although concern has been heightened, as evidence by a 1994 FDA Public Health Advisory. We report a case of radiation-induced dermatitis in a patient undergoing multiple diagnostic and embolization procedures for treatment of a spinal arteriovenous malformation.

The management of extracranial carotid or vertebral artery pseudoaneurysms is controversial. Although some of these lesions resolve spontaneously, many clinicians opt to treat them with trapping procedures that result in vessel sacrifice. We describe two cases in which an intravascular stent was used to obliterate an aneurysm of the extracranial vertebral artery and the internal carotid artery, respectively, while maintaining the patency of the parent vessel. The technique, which has been successful in experimental animal models, shows promise for application in humans.

We report a case of severe posttraumatic arterial vasospasm treated with repetitive intraarterial papaverine infusions. The salient features of the mechanism of action of papaverine are included.

The authors describe a patient with a large intracavernous aneurysm of the right internal carotid artery and a marked decrease in focal brain blood flow induced by temporary carotid balloon occlusion. The patient subsequently underwent a superficial temporal to middle cerebral artery bypass followed by successful carotid occlusion using detachable balloons placed proximal to the aneurysm. Postoperative rCBF demonstrated normal perfusion in the region of the right internal carotid artery distribution as well as normalization of perfusion to a previous area of baseline perfusion abnormality. Cerebral brain blood flow imaging was useful in the initial evaluation as well as the management of this patient.

Human brain activity was evoked by a dynamic random-dot display in which a square-wave grating appeared and disappeared at regular intervals. Grating visibility was determined by one of four different contrasts: texture, stereo disparity, luminance, or color. Scalp fields measured with 31 electrodes were used to estimate epicortical potential fields. The estimation procedure required detailed anatomical data for each subject. These were obtained from magnetic resonance images. A three-dimensional digitizer and a stereotactic headgear were used to accurately merge the frame of reference of the magnetic resonance image with that of the evoked potential. Epicortical potential fields provided a better indicator of where brain activity is evoked than did scalp fields. These procedures also corrected for anatomical variations between scalp and brain from subject to subject. In two right-handed female subjects, evoked activity was observed in the left posterior parietal and the right occipital, parieto-occipital and posterior temporal cortices. Evoked activity was observed in the left parietal cortex for luminance processing, in the right parietal cortex for texture processing and in the right temporal cortex for color processing, which was selective for the particular contrast.

Purpose: To report the development and validation of a technique of dual tracer single-photon emission CT brain imaging using technetium-99m hexamethylpropyleneamine oxime and iodine-123 iodoamphetamine agents and the application of this technique in patients with a variety of diagnoses., Methods: Contamination between the two isotopes' energy windows was calculated by opening both energy windows while scanning a group of patients using a single isotope. To compare uniformity of I-123 down-scatter, Tc-99m studies were performed both before and after the administration of I-123 in five of 24 dual studies. The 24 patients studied with the dual-isotope technique were evaluated during acetazolamide testing, trial balloon occlusion, or embolization of an arteriovenous malformation., Results: In a dual acquisition, average count contamination of an I-123 study by Tc-99m was less than 1% of the total I-123 counts, and contamination of a Tc-99m study by I-123 was approximately 12% of the total Tc-99m counts. Tc-99m studies performed both before and after the administration of I-123 demonstrated that contaminating counts do not adversely affect scan interpretation. Dual-tracer scans were completed in all 24 patients, 10 of whom showed changes after intervention., Conclusions: Dual-tracer single-photon emission CT brain scans of adequate diagnostic quality are possible using Tc-99m and I-123.

A new method is described to calculate epicortical potential fields from scalp fields based on linear algebra. It requires detailed anatomical information, for each subject, obtained from MR images. The calculation is validated in a physical model of the human head and applied to human subjects. The results suggest that the method yields reliable epicortical fields that help to localize evoked cortical activity in humans.

The performance of two methods, used to localize brain activity from evoked potential fields measured on the scalp, was assessed in a tank model of the human head. This physical model contained a human skull encased in a polymer simulating the resistivity and geometry of brain and scalp. The dipole localization method mislocalized the positions of known dipole sources by several centimeters. The mislocalization was systematic. The dipoles were localized too deeply in the head. The Laplacian method yielded a field resembling the brain surface field (epicortical potential field) provided that the iso-potential contours of the scalp field closed within the measurement range. Clipping resulted in a serious mislocalization of the position of the peak of the epicortical potential field.

It is important to determine preoperatively which patients can tolerate permanent occlusion of a cervical internal carotid or cerebral artery when such a procedure may be necessary to treat cerebrovascular or neoplastic lesions. Here we report our experience in combining temporary intra-arterial balloon occlusion with concomitant cerebral blood flow imaging in preoperative evaluation of such patients. Forty-two patients with a variety of cerebrovascular and neoplastic lesions underwent trial balloon occlusion of an internal carotid or intracerebral artery. Eight patients developed both neurologic symptoms as well as brain perfusion defects during trial occlusion. Nine others developed only perfusion defects. The remainder were asymptomatic and had negative scans. Brain blood flow imaging during intra-arterial balloon occlusion identified 17 patients potentially at risk for developing postsurgical ischemic deficits. Treatment alternatives to acute arterial sacrifice were developed for these patients.