Accuracy in Identifying the Source of Subarachnoid Hemorrhage in the Setting of Multiple Intracranial Aneurysms.

BACKGROUND: Subarachnoid hemorrhage cases with multiple cerebral aneurysms frequently demonstrate a hemorrhage pattern that does not definitively delineate the source aneurysm. In these cases, rupture site is ascertained from angiographic features of the aneurysm such as size, morphology, and location. OBJECTIVE: To examine the frequency with which such features lead to misidentification of the ruptured aneurysm. METHODS : Records of patients who underwent surgical clipping of a ruptured aneurysm at our institution between 2004 and 2014 and had multiple aneurysms were retrospectively reviewed. A blinded neuroendovascular surgeon provided the rupture source based on the initial head computed tomography scans and digital subtraction angiography images. Operative reports were then assessed to confirm or refute the imaging-based determination of the rupture source. RESULTS: One hundred fifty-one patients had multiple aneurysms. Seventy-one patients had definitive hemorrhage patterns on initial computed tomography scans and 80 patients had nondefinitive hemorrhage patterns. Thirteen (16.2%) of the cases with nondefinitive hemorrhage patterns had discordance between the imaging-based determination of the rupture source and intraoperative findings of the true ruptured aneurysm, yielding an imperfect positive predictive value of 83.8%. Of all multiple aneurysm cases with subarachnoid hemorrhage treated by surgical or endovascular means at our institution, 4.3% (13 of 303) were misidentified. CONCLUSION: Morphological features cannot reliably be used to determine rupture site in cases with nondefinitive subarachnoid hemorrhage patterns. Microsurgical clipping, confirming obliteration of the ruptured lesion, may be preferentially indicated in these patients unless, alternatively, all lesions can be contemporaneously and safely treated with endovascular embolization.

Reducing length of stay in aneurysmal subarachnoid hemorrhage: A three year institutional experience.

Hospital length of stay is a common metric of excellence in health care. With limited data evaluating hospital length of stay (LOS) and cost in subarachnoid hemorrhage (SAH), in this study we explore multiple prognostic factors and present our institutional experience in shortening LOS. 345 SAH patients were reviewed over a three year period. Patient demographics, hemorrhage grade, hospital course, hospital costs, and LOS were reviewed. Angiogram-negative SAH, Hunt and Hess (HH) Grade 5, and early mortalities were excluded. During this period a physician-led daily multidisciplinary huddle was established to identify and expedite patient discharge needs. 174 patients met inclusion criteria. Significant predictors of increased hospital LOS on univariate analysis included higher HH grade, hydrocephalus, need for ventriculostomy or ventriculoperitoneal shunt, clinical vasospasm, pneumonia, respiratory failure, deep venous thrombosis, and urinary tract infection. Need for shunt, clinical vasospasm, and pneumonia remained significant on multivariate analysis. Mean LOS times decreased to less than those cited in earlier studies, with mean hospital LOS dropping from 21.6days to 14.1. Total hospital costs per SAH patient decreased from $328K to $269K. Readmission rate and breakdown by patient discharge site remained unchanged. Need for ventriculoperitoneal shunt, clinical vasospasm, and pneumonia were found predictive of longer LOS in SAH patients. A physician-led daily multidisciplinary huddle is a potentially valuable tool to identify patient discharge needs and lower LOS and cost in SAH patients.

Safety and efficacy of balloon angioplasty of the anterior cerebral artery for vasospasm treatment after subarachnoid hemorrhage.

Balloon angioplasty is often performed for symptomatic vasospasm following aneurysmal subarachnoid hemorrhage. Angioplasty of the anterior cerebral artery (ACA), however, is perceived to be a challenging endeavor and not routinely performed due to technical and safety concerns. Here, we evaluate the safety and efficacy of balloon angioplasty of the anterior cerebral artery for vasospasm treatment. Patients with vasospasm following subarachnoid hemorrhage who underwent balloon angioplasty at our institution between 2011 and 2016 were retrospectively reviewed. All ACA angioplasty segments were analyzed for pre- and post-angioplasty radiographic measurements. The degree of vasospasm was categorized as mild (<25%), moderate (25-50%), or severe (>50%), and relative change in caliber was measured following treatment. Clinical outcomes following treatment were also assessed. Among 17 patients, 82 total vessel segments and 35 ACA segments were treated with balloon angioplasty. Following angioplasty, 94% of segments had increased caliber. Neurological improvement was noted in 75% of awake patients. There were no intra-procedural complications, but two patients developed ACA territory infarction, despite angioplasty treatment. We demonstrate that balloon angioplasty of the ACA for vasospasm treatment is safe and effective. Thus, ACA angioplasty should be considered to treat vasospasm in symptomatic patients recalcitrant to vasodilation infusion therapy.

Quantitative assessment of parent vessel and distal intracranial hemodynamics following pipeline flow diversion.

Background Pipeline embolization devices (PEDs) are commonly used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intraparenchymal hemorrhage. Although intra-aneurysmal hemodynamic changes have been studied, parent vessel and intracranial hemodynamics after PED use are unknown. We examine the impact of flow diversion on parent artery and distal intracranial hemodynamics. Method Patients with internal carotid cerebral aneurysms treated with PED who had flow volume rate, flow velocities, pulsatility index, resistance index, Lindegaard ratio, and wall shear stress (WSS) obtained after treatment using quantitative magnetic resonance angiography were reviewed. Means were compared between ipsilateral and contralateral internal carotid artery (ICA) and middle cerebral artery (MCA) using paired t tests. Results A total of 18 patients were included. Mean flow volume rate was lower in the ipsilateral versus contralateral ICA ( p = 0.04) but tended to be higher in the ipsilateral versus contralateral MCA ( p = 0.08). Lindegaard ratio was higher ipsilateral to the PED in diastole ( p = 0.05). Although there was no significant difference in flow velocities, pulsatility or resistance indices, and WSS, the two cases in our cohort with hemorrhagic complications did display significant changes in MCA flows and MCA WSS. Conclusion PED placement appears to alter the elasticity of the stented ICA segment, with lower flows in the ipsilateral versus contralateral ICA. Conversely, MCA flows and MCA WSS are higher in the ipsilateral MCA among patients with hemorrhage after PED placement, suggesting the role of disrupted distal hemodynamics in delayed ipsilateral intraparenchymal hemorrhage.

Changes in pulsatility and resistance indices of cerebral arteriovenous malformation feeder arteries after embolization and surgery.

OBJECTIVES: Embolization reduces flow in cerebral arteriovenous malformations (AVMs) before surgical resection, but changes in pulsatility and resistance indices (PI, RI) are unknown. Here, we measure PI, RI in AVM arterial feeders before and after embolization/surgery. METHODS: Records of patients who underwent AVM embolization and surgical resection at our institution between 2007 and 2014 and had PI, RI, and flows obtained using quantitative magnetic resonance angiography were retrospectively reviewed. PI = [(systolic - diastolic flow velocity)/mean flow velocity] and RI = [(systolic - diastolic flow velocity)/systolic flow velocity]. Hemodynamic parameters were compared between the feeder and contralateral artery before and after embolization/surgery. RESULTS: 38 patients were included (6 embolization only, 24 embolization and surgery, 8 surgery only). After embolization, flow volume rates within feeders decreased significantly (p < 0.001) to match flows in their contralateral counterparts (p = 0.78). On the other hand, mean, systolic, and diastolic flow velocities (p = 0.60, 0.32, 0.34, respectively) as well as PI, RI (p = 0.99, 0.68) did not change significantly after embolization. However, after surgery mean, systolic, and diastolic flow velocities within feeders decreased significantly (p = 0.001, 0.002, 0.001, respectively) and PI, RI normalized to match the indices of their contralateral counterparts (p = 0.46, 0.46). CONCLUSION: Following partial AVM embolization, PI, RI are unchanged and flow velocities in feeder arteries also remain unchanged likely due to redistribution of flow through residual nidus. Thus, staged management of AVMs is unlikely to increase outflow resistance and offers a safe treatment strategy.

Relationship of pulsatility and resistance indices to cerebral arteriovenous malformation angioarchitectural features and hemorrhage.

The role that hemodynamics plays in the pathophysiology of cerebral arteriovenous malformation (AVM) hemorrhage remains unclear. Here, we examine the relationship of pulsatility and resistance indices to AVM angioarchitectural features and hemorrhage. Records of patients with cerebral AVMs evaluated at our institution between 2007-2014 and with flows obtained before treatment using quantitative magnetic resonance angiography (QMRA) were retrospectively reviewed. Flow volume rate and flow velocity were measured in primary arterial feeders and compared to their contralateral counterparts. Pulsatility index (PI)=[(systolic flow velocity-diastolic flow velocity)/mean flow velocity] and resistance index (RI)=[(systolic flow velocity-diastolic flow velocity)/systolic flow velocity] were calculated for each feeder and compared to the normal contralateral vessel. Relationships between PI, RI and AVM clinical and angioarchitectural features were assessed using linear regression. Seventy-two patients with a total of 101 feeder arteries were included. PI and RI were significantly lower in AVM arterial feeders compared to normal vessels, thereby resulting in significantly higher flow volume rates and flow velocities in feeder vessels. There was no significant association of PI and RI with hemorrhagic presentation, exclusive deep venous drainage, venous stenosis, single draining vein, or deep location. In conclusion, PI and RI can be measured using QMRA and are lower in AVM arterial feeders compared to normal vessels. Although we found no significant correlation between PI, RI, and AVM angioarchitectural characteristics thought to be associated with increased hemorrhage risk, future studies with larger sample sizes may better elucidate this relationship.

Effect of Hemodynamics on Stroke Risk in Symptomatic Atherosclerotic Vertebrobasilar Occlusive Disease.

IMPORTANCE: Atherosclerotic vertebrobasilar (VB) occlusive disease is a significant etiology of posterior circulation stroke, with regional hypoperfusion as an important potential contributor to stroke risk. OBJECTIVE: To test the hypothesis that, among patients with symptomatic VB stenosis or occlusion, those with distal blood flow compromise as measured by large-vessel quantitative magnetic resonance angiography (QMRA) are at higher risk of subsequent posterior circulation stroke. DESIGN, SETTING, AND PARTICIPANTS: A prospective, blinded, longitudinal cohort study was conducted at 5 academic hospital-based centers in the United States and Canada; 82 patients from inpatient and outpatient settings were enrolled. Participants with recent VB transient ischemic attack or stroke and 50% or more atherosclerotic stenosis or occlusion in vertebral and/or basilar arteries underwent large-vessel flow measurement in the VB territory using QMRA. Physicians performing follow-up assessments were blinded to QMRA flow status. Follow-up included monthly telephone calls for 12 months and biannual clinical visits (for a minimum of 12 months, and up to 24 months or the final visit). Enrollment took place from July 1, 2008, to July 31, 2013, with study completion on June 30, 2014; data analysis was performed from October 1, 2014, to April 10, 2015. EXPOSURE: Standard medical management of stroke risk factors. MAIN OUTCOMES AND MEASURES: The primary outcome was VB-territory stroke. RESULTS: Of the 82 enrolled patients, 72 remained eligible after central review of their angiograms. Sixty-nine of 72 patients completed the minimum 12-month follow-up; median follow-up was 23 (interquartile range, 14-25) months. Distal flow status was low in 18 of the 72 participants (25%) included in the analysis and was significantly associated with risk for a subsequent VB stroke (P = .04), with 12- and 24-month event-free survival rates of 78% and 70%, respectively, in the low-flow group vs 96% and 87%, respectively, in the normal-flow group. The hazard ratio, adjusted for age and stroke risk factors, in the low distal flow status group was 11.55 (95% CI, 1.88-71.00; P = .008). Medical risk factor management at 6-month intervals was similar between patients with low and normal distal flow. Distal flow status remained significantly associated with risk even when controlling for the degree of stenosis and location. CONCLUSIONS AND RELEVANCE: Distal flow status determined using a noninvasive and practical imaging tool is robustly associated with risk for subsequent stroke in patients with symptomatic atherosclerotic VB occlusive disease. Identification of high-risk patients has important implications for future investigation of more aggressive interventional or medical therapies.

Correlation between angiographic transit times and neurological status on admission in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVE: The use of digital subtraction angiography (DSA) for semiquantitative cerebral blood flow(CBF) assessment is a new technique. The aim of this study was to determine whether patients with aneurysmal subarachnoid hemorrhage (aSAH) with higher Hunt and Hess grades also had higher angiographic contrast transit times (TTs) than patients with lower grades. METHODS: A cohort of 30 patients with aSAH and 10 patients without aSAH was included. Relevant clinical information was collected. A method to measure DSA TTs by color-coding reconstructions from DSA contrast-intensity images was applied. Regions of interest (ROIs) were chosen over major cerebral vessels. The estimated TTs included time-to-peak from 0% to 100% (TTP0-100), TTP from 25% to 100% (TTP25-100), and TT from 100% to 10% (TT100-10) contrast intensities. Statistical analysis was used to compare TTs between Group A (Hunt and Hess Grade I-II), Group B (Hunt and Hess Grade III-IV), and the control group. The correlation coefficient was calculated between different ROIs in aSAH groups. RESULTS: There was no difference in demographic factors between Group A (n = 10), Group B (n = 20), and the control group (n = 10). There was a strong correlation in all TTs between ROIs in the middle cerebral artery (M1, M2) and anterior cerebral artery (A1, A2). There was a statistically significant difference between Groups A and B in all TT parameters for ROIs. TT100-10 values in the control group were significantly lower than the values in Group B. CONCLUSIONS: The DSA TTs showed significant correlation with Hunt and Hess grades. TT delays appear to be independent of increased intracranial pressure and may be an indicator of decreased CBF in patients with a higher Hunt and Hess grade. This method may serve as an indirect technique to assess relative CBF in the angiography suite.

Effects of nidus microarchitecture on cerebral arteriovenous malformation hemodynamics.

Intranidal vessel geometry and organization underlying flow within cerebral arteriovenous malformations (AVM) is poorly understood. We examine the relationship between intranidal vessel characteristics and AVM flow. Records of patients with AVM evaluated at our institution between 2007 and 2013 were retrospectively reviewed. Patients were included if surgical specimens were available and flows were obtained before treatment using quantitative magnetic resonance angiography. Intranidal vessels were identified and the diameter and cross-sectional area of each vessel were measured from digitized images of specimen slides. The relationship between vessel diameter, vessel cross-sectional area, AVM volume, and AVM flow was assessed. Twenty-nine patients were included. Mean total number of vessels per specimen was 133. Mean total AVM flow was 340 ± 276 mL/min. Mean vessel diameter ranged from 0.18-2.37 mm and mean vessel cross-sectional area ranged from 0.09-9.46 mm(2). Linear regression analysis showed that total flow is significantly associated with larger AVM volume (R(2)=0.28, P=0.007), but not with number of vessels per section of the specimen (P=0.20) or mean vessel diameter (P=0.92). Exponential regression analysis demonstrated that AVM flow is significantly correlated to the sum of the cross-sectional vessel areas within each specimen (R(2)=0.16, P=0.05). Total AVM flow is significantly related to sum of the cross-sectional areas of all vessels within each nidus, rather than to total number of vessels or mean nidal vessel diameter. This finding suggests that the sum of the cross-sectional areas of intranidal vessels likely determines the resistance to flow within a cerebral AVM.

Neurological outcomes and cure rates of embolization of brain arteriovenous malformations with n-butyl cyanoacrylate or Onyx: a meta-analysis.

BACKGROUND: In the past decade, preoperative endovascular embolization of cerebral arteriovenous malformations (AVMs) became an essential tool in the treatment of these entities. With the current expansion of technology and wide incorporation of new devices, the indications for the use of endovascular embolization have expanded to include embolization for cure. This has been facilitated by the wide use of the new liquid embolic agents (ethylene-vinyl alcohol co-polymer (EVOH)) in addition to n-butyl cyanoacrylate (NBCA). The aim of this study was to review the current published literature for these two agents and report on permanent neurological injuries and cure rate. METHODS: Published literature citing embolization results for AVMs using liquid embolic agents was reviewed. Papers reporting on permanent complication rates and complete angiographic cure were reviewed. A meta-analysis was performed based on these two variables for the two embolic agents. RESULTS: 103 studies met the selection criteria. Poor neurological outcomes for NBCA and EVOH were 5.2% and 6.8%, respectively (OR 1.4; p=0.56). AVM complete obliteration rate was seen in 13.7% in the NBCA group and in 24% in the EVOH group (OR 1.9). This OR decreased to 1.35 in the subgroup analysis for patients treated after the year 2000. CONCLUSIONS: NBCA continues to have a trend towards lower permanent complication rates, but EVOH had higher angiographic cure rates. The recent literature has demonstrated an increase in the cure rate of AVMs with endovascular embolization techniques yet with a possible increase in permanent neurological deficits and mortality.

Detection of unruptured intracranial aneurysms on noninvasive imaging. Is there still a role for digital subtraction angiography?

BACKGROUND: To determine the utility of digital subtraction angiography (DSA) in patients with unruptured intracranial aneurysms (UIA) detected on noninvasive imaging, such as magnetic resonance angiography (MRA) and computed tomography angiography (CTA). The follow-up of patients with untreated UIAs involves serial imaging; however, this diagnosis may be based on false positive (FP) results. We examined the incidence of FPs in our institutional series. METHODS: DSAs performed at our institution from January 2011 to June 2014 were retrospectively reviewed and patients referred with UIA detected on noninvasive imaging were selected. Clinical presentation as well as aneurysm location, size, and number reported on DSA and noninvasive imaging were assessed. RESULTS: Two hundred and eighty six patients (mean age 56.8 years, female 74.8%) with a total of 355 UIA were included. Thirty-one patients had a symptomatic presentation. Analysis per patient showed the pooled FP rate of noninvasive imaging was 15%. MRA FP was 13% (22/171) and CTA FP was 18% (22/120). FP increased significantly with aneurysm size < 3.5 mm on MRA (P < 0.001) and <4.0 mm on CTA (P = 0.01). Mean aneurysm size among symptomatic patients was significantly larger (P < 0.001) as compared to the incidental group (17.8 vs. 7.7 mm). No location was significantly susceptible to false detection of aneurysms. CONCLUSION: DSA detection of FP UIA diagnosed on noninvasive imaging is significantly higher for aneurysms <4.0 mm. Accurate diagnosis with DSA may eliminate the need for further follow-up and its associated negative psychological and economic effects. Within the limitations of this retrospective study, we conclude that DSA has a diagnostic role in small aneurysms detected on noninvasive imaging.

Hemodynamic Features of Symptomatic Vertebrobasilar Disease.

BACKGROUND AND PURPOSE: Atherosclerotic vertebrobasilar disease is an important cause of posterior circulation stroke. To examine the role of hemodynamic compromise, a prospective multicenter study, Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS), was conducted. Here, we report clinical features and vessel flow measurements from the study cohort. METHODS: Patients with recent vertebrobasilar transient ischemic attack or stroke and ≥50% atherosclerotic stenosis or occlusion in vertebral or basilar arteries (BA) were enrolled. Large-vessel flow in the vertebrobasilar territory was assessed using quantitative MRA. RESULTS: The cohort (n=72; 44% women) had a mean age of 65.6 years; 72% presented with ischemic stroke. Hypertension (93%) and hyperlipidemia (81%) were the most prevalent vascular risk factors. BA flows correlated negatively with percentage stenosis in the affected vessel and positively to the minimal diameter at the stenosis site (P<0.01). A relative threshold effect was evident, with flows dropping most significantly with ≥80% stenosis/occlusion (P<0.05). Tandem disease involving the BA and either/both vertebral arteries had the greatest negative impact on immediate downstream flow in the BA (43 mL/min versus 71 mL/min; P=0.01). Distal flow status assessment, based on an algorithm incorporating collateral flow by examining distal vessels (BA and posterior cerebral arteries), correlated neither with multifocality of disease nor with severity of the maximal stenosis. CONCLUSIONS: Flow in stenotic posterior circulation vessels correlates with residual diameter and drops significantly with tandem disease. However, distal flow status, incorporating collateral capacity, is not well predicted by the severity or location of the disease.

Quantitative assessment of changes in cerebral arteriovenous malformation hemodynamics after embolization.

BACKGROUND AND PURPOSE: Embolization reduces flow in arteriovenous malformations (AVMs) before surgical resection, but achievement of this goal is determined subjectively from angiograms. Here, we quantify effects of embolization on AVM flow. METHODS: Records of patients who underwent AVM embolization at our institution between 2007 and 2013 and had flow rates obtained pre- and postembolization using quantitative magnetic resonance angiography were retrospectively reviewed. Total flow was estimated as aggregate flow within primary arterial feeders or flow in single draining veins. RESULTS: Twenty-one patients were included (mean age 35 years, 24% hemorrhagic presentation) with Spetzler-Martin grades 1 to 4. Fifty-four total embolization sessions were performed. The mean AVM flow was 403.4±262.4 mL/min at baseline, 285.3±246.4 mL/min after single session (29% drop, P<0.001), and 102.0±103.3 mL/min after all sessions of embolization (75% drop, P<0.001). Total number of pedicles embolized (P<0.001) and embolization of an intranidal fistula during any session (P=0.002) were significantly associated with total decreased flow postembolization. On multivariate analysis, total pedicles embolized was predictive of total flow drop (P<0.001). However, pedicles embolized per session did not correlate with flow drop related to that session (P=0.44). CONCLUSIONS: AVM flow changes after embolization can be measured using quantitative magnetic resonance angiography. The total number of pedicles embolized after multiple embolization sessions was predictive of final flow, indicating this parameter is the best angiographic marker of a hemodynamically successful intervention. The number of pedicles embolized per session, however, did not correlate with flow drop in that session, likely because of flow redistribution after partial embolization.

Changes in wall shear stress of cerebral arteriovenous malformation feeder arteries after embolization and surgery.

BACKGROUND AND PURPOSE: Wall shear stress (WSS) has been implicated as an important stimulus for vascular remodeling. The purpose of this study is to measure WSS in AVM arterial feeders using quantitative magnetic resonance angiography pre- and post-embolization/surgery. METHODS: Records of patients who underwent AVM embolization and surgical resection at our institution between 2007 and 2013 and had WSS, flow rate, and vessel diameter obtained pre- and post-treatment using quantitative magnetic resonance angiography were retrospectively reviewed. WSS was compared between the feeder and contralateral artery pre- and post-embolization/surgery. RESULTS: Twenty-one patients were included (mean age 34 years, 19% hemorrhagic presentation), with Spetzler-Martin grades 1 to 4. WSS, blood flow, and vessel diameter were assessed in a total of 51 feeder arteries. At baseline, mean WSS was significantly higher compared with the contralateral vessel (29.7±12.0 dynes/cm(2) versus 23.3±11.0 dynes/cm(2); P=0.007). After embolization (23.0 dynes/cm(2) versus 22.5 dynes/cm(2); P=0.78) and surgery (17.9 dynes/cm(2) versus 23.2 dynes/cm(2); P=0.09), WSS was not significantly different than in the contralateral vessel. Reduced WSS post-embolization corresponded to significantly decreased flow (338.1 mL/min versus 170.3 mL/min; P<0.001) and smaller vessel diameter (3.7 mm versus 3.5 mm; P=0.01). CONCLUSIONS: Enlargement of cerebral AVM arterial feeders is insufficient to compensate for increased blood flow, creating high WSS. After treatment, flow diminishes and so WSS and vessel diameter concomitantly decrease. Thus, WSS plays a pivotal role in vascular remodeling that may be exploited to monitor AVM response to treatment or understand other high-flow vascular pathologies.

Intracranial blood flow changes after extracranial carotid artery stenting.

BACKGROUND: Carotid artery stenting is an endovascular treatment option for patients with extracranial carotid stenosis. However, intracranial blood flow changes following stenting have not been established. OBJECTIVE: To determine the effects of stenting on intracranial blood flow. METHODS: Records of patients who underwent stenting at our institution between 2004 and 2012 and had flow rates obtained pre- and poststenting by the use of quantitative magnetic resonance angiography were retrospectively reviewed. Percentage stenosis, stenosis length, and minimum vessel diameter were measured from cerebral angiography images. RESULTS: Eighteen patients were included. Mean age was 65 years with 67% presenting with symptomatic stenosis. Degree of stenosis ranged from 60% to 90%. Internal carotid artery (ICA) mean flow improved significantly poststenting from 174.9 ± 83.6 mL/min to 250.7 ± 91.2 mL/min (P = .011). Ipsilateral middle cerebral artery (MCA) flow, however, was not significantly altered poststenting (107.8 ± 41.6 mL/min vs 114.3 ± 36.3 mL/min; P = .28). Univariate analysis revealed that improved minimum vessel diameter after stenting, but not percentage stenosis (P = .18) or stenosis length (P = .45), is significantly associated with increased ICA flow (P = .02). However, improved percentage stenosis, stenosis length, minimum vessel diameter, and ICA flow poststenting were not significantly associated with increased MCA flow (P = .64, .38, .13, .37, respectively). CONCLUSION: ICA flow was compromised at baseline, improving 43% on average poststenting. Increased minimum vessel diameter was the factor most significantly associated with increased flow. Conversely, MCA flow was not significantly compromised at baseline nor altered after stenting, suggesting compensatory intracranial collateral supply prestenting that redistributes following ICA revascularization.

Augmentation of N-butyl cyanoacrylate embolization of cranial, head, and neck tumors by simultaneous infusion of 5% dextrose solution.

BACKGROUND: N-Butyl cyanoacrylate (NBCA) is an adhesive liquid embolic agent widely used for embolization of cranial, head and neck tumors. Adequate distal penetration of NBCA into vessels with the smallest possible diameter, while preventing its reflux, is still a challenge, even in experienced hands. Simultaneous infusion of 5% dextrose in water solution (D5W) through the guiding catheter has been described before as a technique for improving embolization of dural arteriovenous malformations. OBJECTIVE: To describe our experience with a modified D5W guide catheter push technique during embolization of hemorrhagic cranial, head and neck tumors. The embolization technique and pitfalls which might lead to complications are discussed in detail. MATERIALS: A retrospective series of 20 patients treated with the D5W push technique during embolization of cranial, head and neck lesions between 2007 and 2013 is presented. The goal of embolization was preoperative or palliative embolization of hemorrhagic tumors. Localization and histopathologic diagnosis of lesions, concentration of NBCA used, subsequent surgical treatment, intraoperative blood loss, and complications were evaluated. RESULTS: A total of 44 arterial pedicles were embolized during 22 treatment sessions. Adequate embolization of the lesions was achieved in all cases. Transient ischemic attack due to atheroma embolization (from the aorta) was seen in one patient (4%). Persistent vascularity of tumor associated with minimal intraoperative bleeding was reported in one patient (4%). Recurrence of epistaxis was reported in two patients diagnosed with Osler-Weber-Rendu syndrome. CONCLUSIONS: The D5W push technique during NBCA embolization of cranial, head and neck tumors is a safe and effective method to enhance penetration of the embolizing agent.

Rare presentation of intracranial vascular blowout after tumor resection and radiation therapy.

A middle-aged patient presented with a rapidly growing right dural-based extra-axial posterior clinoid mass extending to the right cavernous sinus that was surgically resected. Histological examination showed solid growth of primitive neuroectodermal tumor arising from the third nerve. Following surgical resection, the patient was further managed by radiation and chemotherapy. Two years later the patient developed new intracranial hemorrhage in the area adjacent to the previous surgical cavity. A cerebral angiogram showed contrast extravasation at the junction of the posterior communicating artery (Pcom) and the right posterior cerebral artery (PCA), with an expanding pseudoaneurysm. This was managed with N-butyl cyanoacrylate embolization. Autopsy showed microscopic recurrence of tumor into the PCA/PCom region with invasion of the wall of the Pcom. This case report illustrates the concept of vascular blowout in intracranial cerebral vasculature. It appears that, in the presence of risk factors that contribute to weakening of vessel walls (surgery, radiation, tumor recurrence), a blowout can occur intracranially.

Effects of extracranial carotid stenosis on intracranial blood flow.

BACKGROUND AND PURPOSE: The hemodynamic effects of extracranial carotid stenosis on intracranial blood flow are not well characterized. We sought to determine the impact of degree of stenosis, stenosis length, and residual lumen on intracranial blood flow in patients with extracranial carotid stenosis. METHODS: Carotid stenosis patients who had undergone both vessel flow rate measurements using quantitative magnetic resonance angiography and digital subtraction angiography were examined. The impact of the anatomic measurements of the stenosis relative to ipsilateral internal carotid artery (ICA) flow and ipsilateral-to-contralateral middle cerebral artery (MCA) flow ratio were assessed. RESULTS: Forty-four patients (mean age, 67 years; 64% symptomatic) were included. Higher percentage stenosis and smaller residual lumen were associated with a significant decrease in ICA flow (P<0.01 and 0.04, respectively). On multivariate analysis, percentage stenosis remained as the primary predictor of ICA flow (P<0.001). MCA flow ratio was not significantly associated with percentage stenosis, stenosis length, or residual lumen. However, mean MCA flow ratio was significantly lower in symptomatic compared with asymptomatic patients (0.92 versus 1.22; P=0.001). In contrast, mean ICA flow ratio was similar among these 2 groups (0.55 versus 0.55; P=0.99). CONCLUSIONS: Percentage stenosis and residual lumen are significantly associated with ICA but not MCA flow, suggesting that local hemodynamic effects of carotid stenosis do not translate directly to distal vasculature, because intracranial flows can be maintained through collaterals. The lower MCA flow ratio in symptomatic patients highlights the potential importance of distal hemodynamics in symptomatic presentation.

Rare presentation of intracranial vascular blowout after tumor resection and radiation therapy.

A middle-aged patient presented with a rapidly growing right dural-based extra-axial posterior clinoid mass extending to the right cavernous sinus that was surgically resected. Histological examination showed solid growth of primitive neuroectodermal tumor arising from the third nerve. Following surgical resection, the patient was further managed by radiation and chemotherapy. Two years later the patient developed new intracranial hemorrhage in the area adjacent to the previous surgical cavity. A cerebral angiogram showed contrast extravasation at the junction of the posterior communicating artery (Pcom) and the right posterior cerebral artery (PCA), with an expanding pseudoaneurysm. This was managed with N-butyl cyanoacrylate embolization. Autopsy showed microscopic recurrence of tumor into the PCA/PCom region with invasion of the wall of the Pcom. This case report illustrates the concept of vascular blowout in intracranial cerebral vasculature. It appears that, in the presence of risk factors that contribute to weakening of vessel walls (surgery, radiation, tumor recurrence), a blowout can occur intracranially.