3-dimensional Rotational Angiography Research Articles

Novel visually guided leadless pacemaker implantation using the latest high-speed intraprocedural 3-dimensional rotational angiography system

Novel visually guided leadless pacemaker implantation using the latest high-speed intraprocedural 3-dimensional rotational angiography system

Assessing the risk of intracranial aneurysm rupture using computational fluid dynamics: a pilot study.

This study compared 2 representative cases with ruptured aneurysms to explore the role of hemodynamic and morphological parameters in evaluating the rupture risk of intracranial aneurysms (IAs). CTA and 3-dimensional rotational angiography (3DRA) of 3 IAs in 2 patients were retrospectively analyzed in this study. Hemodynamics and morphological parameters were compared between a ruptured IA and an unruptured IA in case1, and between before and after aneurysm rupture in case 2. In case 1, the ruptured aneurysm had larger morphological parameters including size ratio (SR), aspect ratio (AR), aneurysm vessel angle (θF), Aneurysm inclination angle (θA), Undulation index (UI), Ellipticity index (EI), and Non-sphericity Index (NSI) than the unruptured aneurysm. And oscillatory shear index (OSI) is also larger. Higher rupture resemblance score (RRS) was shown in the ruptured aneurysm. In case 2, the aneurysm had one daughter sac after 2 years. Partial morphological and hemodynamic parameters including SR, AR, θF, θA, UI, EI, NSI, OSI, and relative residence time (RRT) increased, and normalized wall shear stress (NWSS) was significantly reduced. RRS increased during this period. SR and OSI may have predictive values for the risk of intracranial aneurysm rupture. It is possible that WSS Changes before and after IA rupture, yet the influence of high or low WSS on growth and rupture of IA remains unclear. RRS is promising to be used in the clinical assessment of the rupture risk of IAs and to guide the formulation of treatment plans.

Impact of a selective lens dose reduction protocol in 3D rotational angiography on radiation exposure to the eye lens during cerebral angiography: a randomized controlled trial

BackgroundWe aimed to investigate the radiation dose to the eye lens (lens dose) during cerebral angiography and to evaluate the effectiveness of the lens dose reduction protocol for 3-dimensional rotational...

Topological Data Analysis and Use of Mapper for Cerebral Aneurysm Rupture Status Discrimination Based on 3-Dimensional Shape Analysis.

Topological data analysis (TDA), which identifies patterns in data through simplified topological signatures, has yet to be applied to aneurysm research. We investigate TDA Mapper graphs (Mapper) for aneurysm rupture discrimination. Two hundred sixteen bifurcation aneurysms (90 ruptured) from 3-dimensional rotational angiography were segmented from vasculature and evaluated for 12 size/shape and 18 enhanced radiomics features. Using Mapper, uniformly dense aneurysm models were represented as graph structures and described by graph shape metrics. Mapper dissimilarity scores (MDS) were computed between pairs of aneurysms based on shape metrics. Lower MDS described similar shapes, whereas high MDS represented shapes that do not share common characteristics. Ruptured/unruptured average MDS scores (how "far" an aneurysm is shape-wise to ruptured/unruptured data sets, respectively) were evaluated for each aneurysm. Rupture status discrimination univariate and multivariate statistics were reported for all features. The average MDS for pairs of ruptured aneurysms were significantly larger compared with unruptured pairs (0.055 ± 0.027 vs 0.039 ± 0.015, P < .0001). Low MDS suggest that, in contrast to ruptured aneurysms, unruptured aneurysms have similar shape characteristics. An MDS threshold value of 0.0417 (area under the curve [AUC] = 0.73, 80% specificity, 60% sensitivity) was identified for rupture status classification. Under this predictive model, MDS scores <0.0417 would identify unruptured status. MDS statistical performance in discriminating rupture status was similar to that of nonsphericity and radiomics Flatness (AUC = 0.73), outperforming other features. Ruptured aneurysms were more elongated ( P < .0001), flatter ( P < .0001), and showed higher nonsphericity ( P < .0001) compared with unruptured. Including MDS in multivariate analysis resulted in AUC = 0.82, outperforming multivariate analysis on size/shape (AUC = 0.76) and enhanced radiomics (AUC = 0.78) alone. A novel application of Mapper TDA was proposed for aneurysm evaluation, with promising results for rupture status classification. Multivariate analysis incorporating Mapper resulted in high accuracy, which is particularly important given that bifurcation aneurysms are challenging to classify morphologically. This proof-of-concept study warrants future investigation into optimizing Mapper functionality for aneurysm research.

Technical Feasibility of Renal Artery Embolization on a Transplanted Kidney Due to Intractable Unilateral Hydronephrosis After En Bloc Kidney Transplantation: Case Report.

En bloc kidney transplantation (EBKT) is a technique used to transplant pediatric kidneys to adult recipients, but can lead to certain complications seldom found in single-kidney transplantation. We report a case of renal artery embolization after EBKT due to intractable unilateral hydronephrosis and highlight the technical details and challenges of the procedure. An 18-year-old female with MELAS syndrome underwent EBKT from a 10-month-old male baby. Two months later, the patient developed unilateral hydronephrosis and recurrent urinary tract infections, which was intractable to conventional therapy. Therefore, we underwent embolization of the problematic transplanted left kidney. Owing to the complicated anatomy and multiple angulations, multiple microcatheters, wires and support catheters were needed to select the renal arteries. Repeated procedures were required due to remnant flow from small branches and accessory renal arteries that were not easily visualized by conventional angiography, which were eventually detected by adjunctive use of 3-dimensional rotational angiography. Selective renal artery embolization after EBKT is challenging due to the short renal artery length and multiple angulations, yet it can still be performed safely and effectively by use of meticulous catheter-wire interactions and adjunctive intraoperative imaging techniques to delineate the precise anatomy of the target arteries. Selective renal artery embolization, which is less invasive than nephrectomy, can be considered if the culprit kidney must inevitably be sacrificed in en bloc kidney transplantation.

Reliability of using generic flow conditions to quantify aneurysmal haemodynamics: A comparison against simulations incorporating boundary conditions measured in vivo

Background and objectivesInitiation, growth, and rupture of intracranial aneurysms are believed to be closely related to their local haemodynamic environment. While haemodynamics can be characterised by use of computational fluid dynamics (CFD), its reliability depends heavily upon accurate assumption of the boundary conditions. Herein, we compared the simulated aneurysmal haemodynamics obtained by use of generic boundary conditions against those obtained under flow conditions measured in vivo. MethodsWe prospectively recruited 19 patients with intracranial aneurysms requiring 3-dimensional rotational angiography, during which blood pressure at the internal carotid artery was probed by catheter and flowrate measured by a dedicated software tool. Using these flow conditions measured in vivo, we quantified the aneurysmal haemodynamics for each patient by CFD, and then compared the results with those derived from a generic condition reported in the literature, in terms of the time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and percentage of the intra-aneurysmal flow (PIAF). In addition, the effects on aneurysmal haemodynamics of different outflow strategies (splitting method vs. Murray's Law) and simulation schemes (transient vs. steady-state) relative to each flow condition were also assessed. ResultsDifferences in the simulated TAWSS (−6.08 ± 10.64 Pa, p = 0.001), OSI (0.06 ± 0.13, p = 0.001), and PIAF (−0.05 ± 0.20, p = 0.012) between the patient-specific and generic boundary conditions were found to be statistically significant, in contrast to that in the RRT (49 ± 307 Pa−1, p = 0.062). Outflow strategies did not yield statistically significant differences in any of the investigated parameters (all p > 0.05); rather, the resulting parameters were found to be in good correlations (all r > 0.71, p < 0.001). Difference between the aneurysmal TAWSS and the WSS derived from cycle-averaged flowrate condition was found to be minor (0.66 ± 1.36 Pa, p = 0.000), so was that between PIAFs obtained respectively from the transient and steady-state simulations (0.02 ± 0.05, p = 0.000). ConclusionsIncorporating into simulation the patient-specific boundary conditions is critical for CFD to characterise aneurysmal haemodynamics, while outflow strategies may not introduce significant uncertainties. Steady-state simulation incorporating the cycle-averaged flow condition may produce unbiased WSS and PIAF compared to the transient analysis.

Radiological evaluation of maxillary artery and descending palatine artery in the pterygopalatine fossa by 3D rotational angiography.

The aim of this study is to evaluate the branching patterns and topographical features of the third part of the maxillary artery (t-MA) and descending palatine artery (DPA) by 3-Dimensional Rotational Angiography (3DRA) images and to define the radiological classification of their variations, based upon the previous cadaveric studies and a review of the literature. This study was conducted from May 2020 through June 2021. All consecutive adult patients who were examined with 3D-RA were enrolled in the study. The morphological evaluations and measurements of t-MA, DPA and their branches were made on maximum intensity projection images with 10-20mm slice thickness. Eighty-five hemifaces, including 58 females and 45 right sides, were evaluated. The diameter of the t-MA was measured as 1.73 ± 0.30mm. The most common pattern of the t-MA according to its course was loop type (63/85, 74.1%) and according to branching pattern was Type Ib (29/85, 34.1%). The mean diameter of DPA was 1.19 ± 0.20mm. The DPA presented as a single trunk in 11/85 cases. Type II, which was defined as one lesser palatine artery originating from distal-DPA, was the most common morphological variation (51.8%). 3DRA imaging provides valuable information for vascular anatomical studies. The most common morphological variation related to t-MA, DPA is the distal branching pattern.

Improved Cerebral Arteriovenous Malformation Obliteration With 3-Dimensional Rotational Digital Subtraction Angiography for Radiosurgical Planning: A Retrospective Cohort Study

Anderson, Joshua L BS; Khattab, Mohamed H MD; Sherry, Alexander D BS; Luo, Guozhen MS; Chitale, Rohan V MD; Froehler, Michael T MD, PhD; Fusco, Matthew R MD; Cmelak, Anthony J MD; Attia, Albert MD

Analysis of Morphological-Hemodynamic Risk Factors for Aneurysm Rupture Including a Newly Introduced Total Volume Ratio.

The purpose of this study was to evaluate morphological and hemodynamic factors, including the newly developed total volume ratio (TVR), in evaluating rupture risk of cerebral aneurysms using ≥7 mm sized aneurysms. Twenty-three aneurysms (11 unruptured and 12 ruptured) ≥ 7 mm were analyzed from 3-dimensional rotational cerebral angiography and computational fluid dynamics (CFD). Ten morphological and eleven hemodynamic factors of the aneurysms were qualitatively and quantitatively compared. Correlation analysis between morphological and hemodynamic factors was performed, and the relationship among the hemodynamic factors was analyzed. Morphological factors (ostium diameter, ostium area, aspect ratio, and bottleneck ratio) and hemodynamic factors (TVR, minimal wall shear stress of aneurysms, time-averaged wall shear stress of aneurysms, oscillatory shear index, relative residence time, low wall shear stress area, and ratio of low wall stress area) were statistically different between ruptured and unruptured aneurysms (p < 0.05). By simple regression analysis, the morphological factor aspect ratio and the hemodynamic factor TVR were significantly correlated (r2 = 0.602, p = 0.001). Ruptured aneurysms had complex and unstable flow. In ≥7 mm ruptured aneurysms, high aspect ratio, bottleneck ratio, complex flow, unstable flow, low TVR, wall shear stress at aneurysm, high oscillatory shear index, relative resistance time, low wall shear stress area, and ratio of low wall stress area were significant in determining the risk of aneurysm rupture.

Geometric parameters on MRA source images to differentiate small Proximal Posterior communicating artery aneurysms from Infundibular dilation.

We aimed to assess the accuracy of magnetic resonance angiography (MRA) in the differentiation of small aneurysms versus infundibular dilations (IDs) at the internal carotid artery-posterior communicating artery (ICA-PComA) junction, emphasizing the role of MRA axial source images. This retrospective study consisted of 83 focal arterial protrusions at ICA-PComA junction in 76 patients who underwent both MRA and digital subtraction angiography (DSA)/3-dimensional rotational angiography (3DRA). The diagnostic performance of MRA for differential diagnosis of aneurysm from ID was calculated using DSA/3DRA interpretation as the standard of reference. In addition, long-axis diameter, short-axis diameter, long-axis diameter/short-axis diameter (L/S) ratio, and angle of lesion (angle of the long-axis of lesion with respect to the x-axis) measured on MRA source images were compared between aneurysms and IDs. Sensitivity, specificity, and accuracy of MRA for distinguishing aneurysms from IDs were 74.4% (57.9-87.0%) to 76.9% (60.7-88.9%), 93.2% (81.3-98.6%) to 95.5% (84.5-99.4%), and 85.5% (76.1-92.3%), respectively. Significant differences were found for the long-axis diameter (P<.001), short-axis diameter (P<.001), L/S ratio (P<.05), and angle of the lesion (P<.001) on MRA axial source images between aneurysms and IDs. The angle of the lesion had the highest discriminatory ability (area under the curve = .966 [.902-.994]) to differentiate aneurysms from IDs. An angle of lesion >60° was 89.7% (75.8-97.1%) sensitive and 100% (92.0-100.0%) specific for diagnosis of aneurysm. MRA is a useful imaging modality for distinguishing between aneurysm and ID at the ICA-PComA junction. Furthermore, geometric parameters on MRA axial source images can provide added value in their differentiation.

Commentary: Improved Cerebral Arteriovenous Malformation Obliteration With 3-Dimensional Rotational Digital Subtraction Angiography for Radiosurgical Planning: A Retrospective Cohort Study.

Commentary: Improved Cerebral Arteriovenous Malformation Obliteration With 3-Dimensional Rotational Digital Subtraction Angiography for Radiosurgical Planning: A Retrospective Cohort Study.

Improved Cerebral Arteriovenous Malformation Obliteration With 3-Dimensional Rotational Digital Subtraction Angiography for Radiosurgical Planning: A Retrospective Cohort Study.

Stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVMs) is well-established. Radiographic advantages exist for 3-dimensional rotational digital subtraction angiography (3DRA) over 2-dimensional digital subtraction angiography (2D DSA) in delineating AVM nidus structure for SRS treatment planning. However, currently there is limited to no data directly comparing 2D DSA versus 3DRA in terms of patient outcomes. To investigate whether the use of 3DRA over 2D DSA in radiosurgical treatment planning for AVMs associates with improved clinical outcomes. All AVM patients treated with SRS at our institution between the years 2000 and 2018 were identified. Primary outcomes were obliteration rates and time to obliteration (TTO); secondary outcomes included rates of post-SRS hemorrhage, salvage therapy, and symptomatic radionecrosis. A minimum of 12 mo of follow-up imaging/angiogram post-SRS was required, or alternatively evidence of obliteration on angiogram prior to 12 mo post-SRS. Single predictor and multivariable Cox regression and logistic regression models were constructed to test for association between radiographic, clinical, and treatment factors with outcomes. A total of 75 patients were included. Total 17 patients received 3DRA and 58 patients received 2D DSA, with a median follow-up of 3.29 yr. The 3DRA is significantly associated with improved TTO on single predictor (HR 2.87, 1.29-6.12; P=.0109) and multivariable analysis (HR 2.448, 1.076-5.750; P=.0330) and increased odds of achieving obliteration by 3 yr post-SRS on single predictor analysis (OR 6.044, 1.405-26.009; P=.0157). The 3DRA over 2D DSA in SRS treatment planning for AVMs may result in improved TTO and 3-yr obliteration rates. Further investigation and prospective study are warranted.

An Outcomes Comparison of Patients Treated for Arteriovenous Malformation with LINAC-based Stereotactic Radiosurgery by a Standard Frame-Based Technique or a Frameless Technique Utilizing 3-Dimensional Rotational Angiography

An Outcomes Comparison of Patients Treated for Arteriovenous Malformation with LINAC-based Stereotactic Radiosurgery by a Standard Frame-Based Technique or a Frameless Technique Utilizing 3-Dimensional Rotational Angiography

Association of Anterior Communicating Artery Aneurysms with Triplicate A2 Segment of the Anterior Cerebral Artery

Triplicate A2 segment of the anterior cerebral artery is a rare anatomical variant (1%-3% prevalence) that which is thought to result mainly from persistence of the embryonic median artery of the corpus callosum. We sought to determine whether the triple-A2 variant is specifically associated with anterior communicating artery (ACoA) aneurysm. We reviewed 2-dimensional digital-subtraction angiography (2D-DSA) as well as 3-dimensional rotational angiography (3D-RA) images of 55 patients with ACoA aneurysms who presented for evaluation and treatment between 2009 and 2014 at our institution. The criteria for definitively obtaining an accurate accounting of all A2 segments was presence of adequate cross-filling across the ACoA on 2D-DSA or 3D-RA imaging, or ability to fuse left and right 3D-RA images. Patients whose imaging did not meet these criteria were excluded from further analysis. We obtained a definitive count of all A2 segments in 36 patients. Among these, 19 patients (5 with the triple-A2 variant) were treated surgically, and 17 patients (2with the triple-A2 variant) were treated endovascularly. The triple-A2 variant was seen in 7 patients. The prevalence of triple-A2 variant among patients with ACoA aneurysm was 19.4%. Patients with ACoA aneurysms had a significantly higher prevalence of the triple-A2 variant compared with the general population (P < 0.00001). Compared with the normal population, patients with ACoA aneurysms deemed to require treatment have a significantly higher likelihood of having triplicate A2 segment. Knowledge of this anatomical variation is of critical importance in planning and executing endovascular and microsurgical treatment of ACoA aneurysms.

A comparative outcomes analysis of patients treated for arteriovenous malformation with LINAC-based stereotactic radiosurgery by a standard frame-based technique or a frameless technique utilizing 3-dimensional rotational angiography

Previous work at our institution treating arteriovenous malformation (AVM) with radiosurgery (RS) demonstrated superior nidus visualization and geometric accuracy with use of 3-dimensional rotational angiography (3DRA) compared to biplanar digital subtraction angiography. We have since adopted a unique radiosurgical protocol that utilizes 3DRA in the planning of linear accelerator (LINAC)-based RS delivered in a frameless manner. This study seeks to compare clinical outcomes between patients treated by this novel approach and those treated by our historic frame-based protocol. Clinical data were queried for all patients treated for AVM by single-fraction RS from 2003 to 2017. RICs were identified and classified as radiologic, symptomatic, or permanent. Excellent outcome was defined as nidus obliteration without intracranial hemorrhage (ICH) or symptomatic RIC. Clinical predictors of study outcomes were identified through univariate and multivariate logistic regression using backwards elimination to optimize a predictive model. 131 AVMs in 124 patients were included with a median follow-up of 88 months. 59 AVMs received frame-based RS and 72 AVMs received frameless RS. Rate of obliteration was 64% for frame-based RS and 61% for frameless RS (p = 0.70). Radiologic, symptomatic, and permanent RICs rates were 68%, 17%, and 8%, respectively, for frame-based cases, versus 40% (p < 0.01), 8% (p = 0.13), and 3% (p = 0.15), respectively, for frameless cases. Excellent outcome was achieved in 49% of frame-based cases and 53% of frameless cases (p = 0.68). These results illustrate the safety and effectiveness of frameless LINAC-based AVM RS utilizing 3DRA.

A unique temporary collateral pathway between carotid-vertebrobasilar arteries in a carotid dissection patient

BackgroundIn adults, the anastomosis between carotid and vertebrobasilar arteries is usually the posterior communicating artery, sometimes the primitive trigeminal artery. In this case, the basilar artery fed the internal carotid artery through the pontine-to-tentorial artery anastomosis after severe stenosis from traumatic carotid dissection.Case presentationA 32-year-old female was diagnosed with ischemic stroke caused by traumatic carotid artery dissection. Aspirin (100 mg/day) and clopidogrel (75 mg/day) were prescribed. Digital subtraction angiography performed 6 days after stroke onset showed a dissection in the cervical segment of left internal carotid artery with severe local stenosis, and a collateral pathway from BA to the cavernous segment of internal carotid artery through the lateral pontine and tentorial artery. Without interventional therapy, clinical symptoms improved significantly within 10 days after onset. At 3-month follow-up, left common carotid artery angiography showed the stenosis had been significantly improved with a residual aneurysm. There was no collateral pathway between carotid-vertebrobasilar arteries, and a residual small artery originated from the posterior vertical segment of cavernous internal carotid artery. The small artery was clearly visualized by 3-dimensional rotational angiography and identified the tentorial artery.ConclusionTo the author’s knowledge, this is the first report of a collateral pathway between carotid vertebrobasilar arteries through the pontine-to-tentorial artery anastomosis. Meanwhile, tentorial artery origination directly from the cavernous segment of internal carotid artery is rare and easily mistaken for persistent primitive trigeminal artery. 3-dimensional rotational angiography can provide sensitive and accurate diagnostic assessment of the small artery, and may be a useful tool for screening of abnormal small arteries.

Advances in 3D angiography for spinal vascular malformations

Spinal vascular malformations are difficult to diagnose lesions that can be associated with significant permanent morbidity. The angioarchitecture of spinal vascular anatomy and the associated pathologies have only recently been illuminated by the advent of spinal angiography. However, conventional spinal digital subtraction angiography is often limited by significant variability, overlapping vessels, as well as an inability to understand the precise location of the nidus or fistula in relation to the spinal cord and spine. In this study, we present 4 unique cases wherein 3-dimensional rotational angiography (3DRA) with dual volume acquisition was useful in defining the anatomy of spinal fistulas as well as planning treatment.

Amended Intraoperative Neuronavigation: Three-Dimensional Vascular Roadmapping with Selective Rotational Digital Subtraction Angiography

Accuracy of intraoperative cerebrovascular neuronavigation is difficult to maintain because of the ongoing need for brain shift correction. By including 3-dimensional rotational intraoperative digital subtraction angiography (3D-iDSA), the intraoperative cerebrovascular neuronavigation can be updated and upgraded throughout the microneurosurgical procedure. The aim of this technical note is to demonstrate the feasibility and advantage of updating and upgrading the accuracy of targeted cerebrovascular neuronavigation with an intraoperative 3D-DSA dataset. A preoperative diagnostic selective 3D-DSA was registered with the neuronavigation software, followed by the automated segmentation of the vascular object of interest (an aneurysm in this case). After acquiring additional 3D-iDSA volumes, these steps were repeated, thereby updating the cerebrovascular roadmap and neuronavigation accuracy (i.e., brain shift correction). This technique was applied successfully in a patient who underwent elective microneurosurgical clipping of a right-sided middle cerebral artery (MCA) bifurcation aneurysm in a hybrid neurosurgical operating setting. After clipping of the MCA aneurysm, a selective 3D iDSA was performed that was then used to update the projection and accuracy of the initial 3D neurovascular object of interest (i.e., the aneurysm). In this revised rotational view, the projection refined the target segments of the clipped MCA aneurysm, the accuracy of clipping, and brain shift correction. 3D-iDSA vascular segmentations can update und upgrade the intraoperative neurovascular roadmap by thereby enhancing accuracy of cerebrovascular neuronavigation, as well as correcting brain shift. This technique is feasible within the hybrid operation room. Evaluation in larger series is required to support these findings.

Giving up knowledge is almost never a good idea: an interview with Dr Evan Zahn.

The history of congenital interventional cardiology has seen numerous groundbreaking innovations typically related to the introduction of a new device or a novel treatment technique. Similarly, imaging of cardiac defects has changed dramatically over the past decades, although some of the advancements have seemed to omit the catheterisation laboratories. Rotational angiography, one of the imaging techniques for guidance of cardiac catheterisation currently referred to as "advanced", in fact was described already in 1960s.1 More recently its improved version, including three-dimensional reconstruction (3DRA), became a valuable intra-procedural imaging tool in interventional cardiology and neuroradiology.2 Dr Evan Zahn was one of the pioneers of 3DRA in the field of congenital cardiology, setting an example for many to follow. With his innovative publication and subsequent lecture at 2011 Pediatric and Adult Interventional Cardiac Symposium (PICS-AICS) on "The Emerging Use of 3-Dimensional Rotational Angiography in Congenital Heart Disease" he motivated many to explore benefits of this modality to strive for improved procedural outcomes and reduced patients' burden of cardiac catheterisation3. I was one of those to take Dr Zahn's thoughts and implement them into routine workflow.4-6 However, almost a decade after Dr Zahn shared his important work, despite tremendous efforts by teams from Utrecht, (Netherlands) and Columbus (Ohio, United States of America) to popularise 3D imaging in catheterisation laboratory during dedicated meetings, two-dimensional (2D) angiography does not seem to be threatened in many, otherwise-progressive, laboratories. During the recent 30th Japanese Pediatric Interventional Cardiology (JPIC) meeting I had the opportunity to ask Dr Zahn why giving up knowledge is almost never a good idea, what is technology's natural order of things, and why the technology has to be more than just exciting, pretty, and new.

An Outcomes-based Analysis of Patients Treated for Arteriovenous Malformation by Frameless LINAC-based Stereotactic Radiosurgery Using 3-Dimensional Rotational Angiography

Arteriovenous Malformation (AVM) nidus localization remains a significant radiosurgical challenge. Previous work at our institution utilizing phantom models demonstrated superior nidus visualization and geometric accuracy with use of 3-dimensional rotational angiography (3DRA) compared to digital angiography orthogonal image pairs. Incorporation of 3DRA into the radiosurgery (RS) planning process in 2009 has since allowed for a frameless LINAC-based approach to treatment. We evaluated clinical outcomes for patients treated in the time since adopting this technique. Clinical data were queried for all patients treated at our institution for AVM by single-fraction RS from 2010 to present. Post-RS surveillance for nidus obliteration and radiation-induced changes (RIC) consisted of an MRI every six months for two years, then annually. Beyond two years, confirmatory cerebral angiography was recommended for any patient with MRI suggestive of nidus obliteration. Patients were excluded if they lacked sufficient post-RS radiographic assessment, defined as either MRI, CTA, or cerebral angiography at least two years after RS. Maximum diameter (MD) and volume were measured for each lesion and used to calculate a modified Radiosurgery-based AVM Score (mRBAS). RICs were identified and classified as radiologic, symptomatic, or permanent. Excellent outcome was defined as nidus obliteration without intracranial hemorrhage (ICH) or symptomatic/permanent RIC. Clinical predictors of study outcomes were identified through univariate and multivariate (MVA) logistic regression and backwards elimination was used to optimize a predictive model for each outcome. A total of 65 AVMs in 62 patients were included with a median follow-up of 67 months. Median age at treatment was 31 years. Of these lesions, 58% presented with ICH. Prior intervention took place in 23% of cases. Median MD, volume, and mRBAS were 2.3cm, 1.93cc, and 1.16, respectively. 3DRA was utilized during treatment planning in 78% of cases. Treatments were delivered to a median isocenter and periphery dose of 2000 cGy and 1600 cGy, respectively. Obliteration was observed in 63% of cases with 88% confirmed angiographically. Median time-to-obliteration was 32 months. Radiologic, symptomatic, and permanent RICs developed in 40%, 8%, and 3% of cases, respectively. Post-RS ICH occurred in four patients with one ICH-related death. MVA showed that younger age and smaller MD predicted for obliteration. Larger MD predicted for radiologic RIC. Female gender and lower mRBAS predicted for excellent outcome. Incorporation of 3DRA in the RS planning process has allowed for a frameless approach to AVM treatment. Since instituting this technique, we have achieved obliteration and excellent outcome rates comparable to frame-based approaches with minimal treatment-related morbidity.