A Nicholson

Superselective Intra-Arterial Ethanol Sclerotherapy of Feeding Artery and Nidal Aneurysms in Ruptured Cerebral Arteriovenous Malformations.

SUMMARY: In the endovascular treatment of cerebral arteriovenous malformations, ethanol sclerotherapy is seldom used due to safety concerns. However, when limited reflux of an embolic agent is permissible or when there is a long distance to the target, ethanol may be preferable. We reviewed 10 patients with 14 cerebral AVM feeding artery aneurysms or intranidal aneurysms treated with intra-arterial ethanol sclerotherapy at our institution between 2005 and 2014. All patients presented with acute intracranial hemorrhage. Thirteen of 14 aneurysms were treated primarily with 60%–80% ethanol into the feeding artery. Complete target feeding artery and aneurysm occlusion was seen in all cases; 8/13 (62%) were occluded by using ethanol alone. No retreatments or recurrences were seen. One permanent neurologic deficit (1/13, 7.7%) and no deaths occurred. In a subset of ruptured cerebral AVMs, ethanol sclerotherapy of feeding artery aneurysms and intranidal aneurysms can be performed with a high degree of technical success and a low rate of complication.

Tips and tricks to optimize MRI protocols for cutaneous vascular anomalies

Magnetic resonance imaging (MRI) serves as the principal imaging modality to diagnose and plan treatment for children with cutaneous vascular anomalies. While routine MRI protocols can lead to the correct diagnosis in the majority of cases, the imaging appearances can sometimes be nonspecific or confusing, yielding more than one possible diagnosis. This review highlights specific MRI sequence recommendations and scanning tips that can optimize the imaging protocol to increase diagnostic confidence.

Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging.

Background and Purpose To evaluate the ability of IA MR perfusion to characterize meningioma blood supply. Methods Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA) and intravenous (IV) T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA) dural, internal carotid artery (ICA) dural, or pial. MR perfusion data regions of interest (ROIs) were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM), relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and mean transit time (MTT). Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling. Results 18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11), ICA dural (n = 4), or pial (n = 3). FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion.

Predictors of intracranial hemorrhage volume and distribution in brain arteriovenous malformation

Background and purpose Despite evidence regarding risk factors for brain arteriovenous malformation (bAVM)-associated spontaneous intracranial hemorrhage (ICH), few data exist describing the spectrum of clinical outcomes that bAVM-associated ICH may manifest. This study aimed to identify the demographical, clinical, and bAVM anatomical variables associated with ICH volume and the presence of intraventricular hemorrhage (IVH) of ruptured bAVMs, two indicators of worse clinical outcome, to help better predict outcome for unruptured bAVMs. Methods Computed tomography images (n = 169) of patients with ruptured bAVM in a prospectively maintained institutional database were retrospectively reviewed to calculate ICH volume and the presence or absence of IVH. Demographic, clinical, and bAVM characteristics information was summarized and analyzed with univariable and multivariable regression models to identify the associations of these features with ICH volume and the presence of IVH. Results Patient sex, exclusively deep venous drainage, and lobar location were associated with ICH volume in univariable analysis; exclusively deep venous drainage remained significant in multivariable analysis (PI = 0.33, 95% CI: 0.21–0.52, p < 0.001). Exclusively deep venous drainage, multiple feeding arteries, and venous stenosis were associated with IVH in univariable analysis; exclusively deep venous drainage (OR = 7.27, 95% CI: 1.94–27.29, p = 0.003) remained significant in multivariable analysis. Conclusions Variables associated with ICH volume and the presence of IVH in ruptured bAVMs were evaluated and identified. They impart information that may help predict the clinical outcome of unruptured bAVM, in turn aiding clinicians in treatment planning.

Effects on vessel measurement accuracy and subsequent occlusion after calcium channel blocker infusion during treatment of cerebral aneurysms with the Pipeline embolization device

Introduction/Purpose To achieve aneurysm occlusion, flow diverters (FDs) must be accurately sized to maximize coverage over the neck and induce thrombosis. Catheterization for diagnostic angiography can cause vasospasm that may affect vessel measurements. This study evaluates impacts of intra-arterial infusion of a calcium channel blocker (CCB) on angiographic measurements in patients treated with FDs to determine effects on final diameter of the FD and subsequent occlusion. Materials and methods Pre-treatment measurements were recorded for diameter of the distal and proximal landing zones and maximum and minimum diameters between these segments. Post-treatment measurements of the stent following deployment were recorded at these locations. When CCB was infused, post-infusion pre-treatment measurements were recorded. Rates of occlusion were noted for all patients. T-tests were performed to assess for differences in pre- and post-treatment measurements and rates of occlusion between groups with and without CCB infusion. Results Twenty-eight FDs were deployed to treat 25 aneurysms in 24 patients. CCB infusion was performed prior to deployment of 12 (42.9%) devices. No significant difference was noted between groups for pre- and post-treatment measurement changes. Confirmed aneurysm occlusion was more likely to occur in the CCB infusion group (88.9% vs. 36.4%, p = 0.009). Conclusion Optimization of device sizing is important to increase FD density over the aneurysm neck and promote thrombosis. To improve measurement accuracy, CCB infusion can reduce effects of mild vasospasm. Subsequent aneurysm occlusion was more likely to occur following FD treatment when device size selection was based on measurements performed following CCB infusion.

Interventional magnetic resonance imaging guided carotid embolectomy using a novel resonant marker catheter: demonstration of preclinical feasibility

To assess the visualization and efficacy of a wireless resonant circuit (wRC) catheter system for carotid artery occlusion and embolectomy under real-time MRI guidance in vivo, and to compare MR imaging modality with x-ray for analysis of qualitative physiological measures of blood flow at baseline and after embolectomy. The wRC catheter system was constructed using a MR compatible PEEK fiber braided catheter (Penumbra, Inc, Alameda, CA) with a single insulated longitudinal copper loop soldered to a printed circuit board embedded within the catheter wall. In concordance with IACUC protocol (AN103047), in vivo carotid artery navigation and embolectomy were performed in four farm pigs (40–45 kg) under real-time MRI at 1.5T. Industry standard clots were introduced in incremental amounts until adequate arterial occlusion was noted in a total of n=13 arteries. Baseline vasculature and restoration of blood flow were confirmed via MR and x-ray imaging, and graded by the Thrombolysis in Cerebral Infarction (TICI) scale. Wilcoxon signed-rank tests were used to analyze differences in recanalization status between DSA and MRA imaging. Successful recanalizations (TICI 2b/3) were compared to clinical rates reported in literature via binomial tests. The wRC catheter system was visible both on 5° sagittal bSSFP and coronal GRE sequence. Successful recanalization was demonstrated in 11 of 13 occluded arteries by DSA analysis and 8 of 13 by MRA. Recanalization rates based on DSA (0.85) and MRA (0.62) were not significantly different from the clinical rate of mechanical aspiration thrombectomy reported in literature. Lastly, a Wilcoxon signed rank test indicated no significant difference between TICI scores analyzed by DSA and MRA. With demonstrated compatibility and visualization under MRI, the wRC catheter system is effective for in vivo endovascular embolectomy, suggesting progress towards clinical endovascular interventional MRI.

P-025 Calcium Channel Blocker Infusion Improves Vessel Measurement Accuracy and Aneurysm Occlusion Following Flow Diversion

Introduction/purpose To best achieve complete occlusion of aneurysms treated with flow diverters (FDs), devices must be accurately sized to precisely match the parent vessel diameter. Appropriately sized FDs will have maximal coverage over the aneurysm neck and will be more likely to induce thrombosis. Catheterization for diagnostic angiography can cause vasospasm that may affect vessel measurements. This study evaluates the effects of intra-arterial infusion of a calcium channel blocker (CCB) on angiographic measurements in patients treated with FDs, investigating the impact on the final diameter of the expanded stent following deployment and subsequent occlusion. Materials and methods Retrospective analysis was performed of prospectively maintained procedure records to identify patients with aneurysms treated with FDs. In all patients, pre-treatment measurements were recorded for vessel diameter of the distal and proximal landing zones, as well as maximum and minimum diameters between these segments. Post-treatment measurements of the stent itself following deployment were recorded at the distal and proximal ends in addition to maximum and minimum diameters. When CCB was infused prior to treatment, post-infusion pre-treatment measurements were recorded. All measurements were performed after calibrating to a catheter included on the image. Rates of occlusion and time to confirmed occlusion were noted for all patients. Independent-sample 2 tailed T-tests were performed to assess for differences in pre- and post-treatment measurements, rates of occlusion, and time to confirmed occlusion between groups with and without CCB infusion. Results 21 FDs were deployed to treat 19 aneurysms in 18 patients. CCB infusion was performed prior to deployment of 9 devices. The change in measurements noted after CCB infusion are summarized in Table 1. No significant difference was noted between groups for pre- and post-treatment measurement changes. Subsequent aneurysm occlusion was more likely to occur in the CCB infusion group (100% vs. 44.4%, p < 0.001). No significant difference was noted between groups for time to occlusion (313.7 vs. 392.8 days, p = 0.807) or overall angiographic follow up time (209.1 vs. 302.5 days, p = 0.326).Abstract P-025 Table 1 Diameter change after CCB infusion Measurement Change Distal Landing Zone 30.2% Proximal Landing Zone 44.3% Maximum Diameter 60.7% Minimum Diameter 8.4% Conclusion Optimization of device sizing is important to increase FD density over the aneurysm neck and promote thrombosis. To improve accuracy of measurements of parent vessels prior to device selection, CCB infusion can reduce the effects of mild vasospasm. In this study, subsequent aneurysm occlusion was more likely to occur following FD treatment when device size selection was based on measurements performed following CCB infusion. Disclosures M. Alexander: None. R. Darflinger: None. F. Settecase: None. A. Nicholson: None. D. Cooke: None. M. Amans: None. S. Hetts: None. C. Dowd: None. R. Higashida: None. V. Halbach: None.

P-024 Prominent Condylar Veins Causing Pulsatile Tinnitus: Dynamic Angiographic Confirmation

Introduction/purpose Numerous processes can cause pulsatile tinnitus (PT), some of which are potentially life threatening. This case series describes a cause of PT – prominent condylar veins – that has undergone little investigation to date. This report characterizes angiographic findings in patients with prominent condylar veins and means to localize symptoms to these structures using dynamic angiography with head positioning and venous balloon test occlusion. Materials and methods Retrospective analysis was performed under IRB approved protocol for 43 consecutive PT patients referred for diagnostic angiography at a major academic medical center between January 2013 and December 2015. Rates of different etiologies of PT among patients in this group were noted. In addition to standard diagnostic cervicocerebral angiography, dynamic angiography with head turning was conducted. The effects of provocative maneuvers were measured using time-resolved flow analysis known (iFlow, Siemens Healthcare, Erlangen Germany). Results 5 (11.6%) patients were found to have prominent condylar veins. 16 (37.2%) had a dAVF, 4 (9.3%) had a venous diverticulum, and 9 (20.9%) had no angiographic abnormality detected. The findings of the five patients with prominent condylar veins are summarized in the table. Representative images are provided in the figure.Abstract P024 Figure 1Abstract P024 Table 2 Conclusion Prominent flow in condylar veins should be considered among the numerous causes of PT. This may be a frequent cause of these symptoms in patients who previously would have had no identifiable cause Further investigation is warranted with respect to this cause of PT and PT in general. Disclosures M. Alexander: None. K. Meisel: None. V. Halbach: None. R. Darflinger: None. A. Nicholson: None. F. Settecase: None. D. Cooke: None. R. Higashida: None. C. Dowd: None. S. Hetts: None. M. Amans: None.

E-087 Virtual Angiographic Reconstructed Projections from Four-Dimensional Digital Subtraction Angiography Acquisition, A Feasibility Study

Introduction/purpose Digital subtraction angiography (DSA) remains the gold standard for the evaluation of extra- and intracranial vascular pathology. Typically, acquisition of multiple angiographic projections is needed to either elongate the vessel(s) of interest or to separate overlapping vessels. Acquiring multiple projections for each selected vessel is costly in terms of time, contrast load, and radiation exposure. Three dimensional digital subtraction angiography (3 DDSA) enabled angiographers to evaluate single vessel injections in multiple projections. Four dimensional digital subtraction angiography (4 DDSA) provides time-resolved 3D acquisition of both the arterial and venous phases of angiography. The aim of this paper is to evaluate the overall quality of processed 4 DDSA to discriminated vascular pathology from normal anatomy. Materials/methods 3 D DSA acquisition was performed to capture primarily arterial phase (260 deg, 1.5 deg/f, rotation duration: ~6 s, 172 projections, 0.36 μGy/projection) or both arterial and venous phases (260 deg, 0.85 deg/f, rotation duration: ~12 s, 304 projections, 0.36 μGy/projection). Projection images obtained from the rotational acquisition were combined with the constraining 3D-DSA vascular volumes in order to form a time resolved 4 DDSA. Using an edge enhanced reconstruction kernel, the 4 DDSA volume was visualized with either a smooth or sharp image characteristic with a slice matrix of 512 × 512. This was then reconstructed into a Virtual Angiography image (Siemens). A secondary reconstruction of the mask phase of each DSA run was also performed to obtain soft tissue and bone anatomical information, from which standard biplane angiographic projections of the 4 DDSA were reconstructed. Windowing, contrast, brightness and opacity levels were adjusted. Single frame images of processed 4 DDSA acquisitions were then evaluated by our Inerventional Neuroradiology staff, as were the corresponding standard biplane projections. Images were graded on overall quality (0 = nondiagnostic, 1 = poor, 2 = acceptable, 3 = good) and ability to discriminate pathology from normal vascular anatomy. Results were compared using standard multivariate two-sample t-test. Results Four internal carotid artery and one vertebral artery injection were evaluated. All vessels had positive findings. Evaluators identified all positive findings on both 4 DDSA and standard DSA images. There was no significant difference in ability to clear the key branch points or vessels between standard and 4 DDSA (3.84 vs. 3.65, p = 0.220). The standard DSA image quality was significantly better than 4 DDSA (20.0 vs. 11.2, p < 0.001) in composite quality scoring. Conclusions Pathology was clearly delineated from normal vascular anatomy on 4 DDSA. However, the quality of the processed 4 DDSA images remains inferior to standard DSA projections. 4 DDSA image quality may may be improved by optimizing acquisition parameters and injection rates, but this work illustrates significant limitations in the current post-processing algorithm as the source data demonstrates better quality and resolution prior to processing. As the acquisition and post-processing software improve, single injection 4 DDSA offers distinct advantages of decreased study time, contrast dose, and radiation exposure. Disclosures L. Pung: 5; C; Siemens Medical Solutions. R. Darflinger: None. J. Yu: None. M. Alexander: None. A. Nicholson: None. F. Settecase: None. T. Moore: 5; C; Siemens Medical Solutions. M. Amans: None. S. Hetts: None. D. Cooke: None.

O-037 MRI-Guided Sclerotherapy for Intraorbital Vascular Malformations: An Updated Experience

Introduction/purpose Despite benign histology, many congenital intra-orbital lesions have an aggressive prognosis owing to the confined orbital space and the intimate optic nerve association – resulting in pain, disfigurement, and vision loss. Complete surgical excision while preserving function may not be possible1 The use of conventional fluoroscopically guided interventions is limited due to inability to visualize soft tissue anatomy. We have previously presented our work evaluating the feasibility of applying interventional MRI technology to access and treat these challenging intraorbital lesions, and now present an update with new patients and multi-year follow up. Materials and methods Ten MRI-guided sclerotherapy procedures were performed on 4 patients (4M, 0F, age = 3–30y) presenting with cystic congenital intraorbital lesions. Patients presented with proptosis (n = 3), visual impairment (n = 2), diplopia (n = 1), ecchymosis (n = 2), and/or pain (n = 1). All procedures were exclusively performed within an interventional MRI suite with an in-room monitor used for real-time needle guidance, injection monitoring and bedside scanner operation. A 22 g MR-compatible needle was inserted into the targeted lesions under “MR-fluoroscopy” using triorthogonal image plane guidance2 to interactively monitor the needle on continuously updated sets of true-FISP images (TR/TE, 4.35/2.18; FA, 60°; NSA, 3; TA, 3.11 s/slice). 0.6% gadolinium was mixed with 5% Ethanolamine Oleate (Ethamolin®) (0.15 ml:1.0 ml vol.) and injected under real-time monitoring using a triorthogonal FLASH sequence (TR/TE,2484/5.4). Follow up on the earliest patients is available for three years. Results Intra-orbital needle insertion and subsequent repositioning were sucesfully performed in all cases. The flexibility of triorthogonal guidance was most helpful in accessing the intraconal retrobulbar space. Active monitoring of sclerosing agent was persistently achieved on 3 planes. Targeted lesions ranged between 1.5 and 4 cm. Three lesions encircled/abutted the optic nerve. Between 1–5.5 mls of sclerosing material were injected per procedure. The smallest lesion was completely filled with sclerosant during each of 2 treatment sessions, with 3 partially filled to avoid excessive intraorbital pressure. Local edema and bruising were a standard finding for 1–2 weeks afterwards. Complete imaging resolution of one lymphatic malformation occurred. The 3 other lesions significantly shrank, without delayed complications. Conclusion This report demonstrates long term success in using MRI technology to treat congenital intraorbital lesions, with no long term or delayed complications to date. This offers a new avenue for those patients who are typically deprived of surgical and other conventional interventional options.Abstract O-037 Figure 1 3-year-old male with a complex right-sided rectrobulbar slow flow vascular malformation encasing the optic nerve. The patients presented with proptosis, ecchymosis, squint, and visual impairment. He was subjected to 2 prior unsuccessful surgical interventions (a:1-3) are axial, sagittal, and coronal T2-Wis demonstrating the extent of malformation prior to MRI-guided sclerotherapy. (b:1-3) are the corresponding scans obtained 6 weeks after the first sclerotherapy session. (c:1-3) are the same scans obtained 12 weeks after the first, and second session of sclerotherapy. There has been significant shrinkage of the overall dimensions of the malformation and reduction of proptosis References 1 Chung EM, et al. Radiographics 2007;(27):1777–799. 2 Derakhshan JJ, et al. Proc ISMRM 15:487 (2007). Disclosures A. Nicholson: None. T. Powell: None. J. Saunders: None. B. Hayek: None. T. Wojno: None. S. Nour: None.