Stent-assisted reconstructive endovascular repair of intracranial aneurysms: long-term clinical and angiographic follow-up

Abstract Background and Purpose: The development of self-expanding stents dedicated to intracranial use has significantly widened the applicability of endovascular therapy to many intracranial aneurysms. The purpose of this study was to report the angiographic and clinical outcomes of wide-necked intracranial aneurysms treated with stent. Methods: Between January 2007 and October 2011 we deployed 22 stents in 20 patients with wide-necked cerebral aneurysms. Inclusion criteria restricted the group to adult patients with wide-necked intracranial aneurysms (ruptured and unruptured lesions). Immediate post-procedural angiographic studies were performed to evaluate successful occlusion of the aneurysm as well as patency of the parent vessel. We assessed long term angiography follow-up to detect in-stent stenosis, progressive thrombosis, recurrence and need for retreatment. Clinical outcome was assessed with the modifing Ranking Scale (mRS). Results: Technical success was obtained in all 22 (100%) cases. Angiography immediately after treatment procedure showed complete occlusion in 7 aneurysms (35%), neck remnant in 11 (55%), incomplete occlusion in 1 (5%) and partial occlusion in 1 (5%). During the endovascular embolization procedure no rupture of the sac or bleeding complication occurred; none of the patients needed undergoing surgical crossover. Procedure-related adverse events occurred in one (5%) patient: a brachial artery pseudoaneurysm. Three (15%) patients had neurological complications after procedure, whose 1 (5%) transitory complication spontaneusly resolved. Two patients (10%), had acute complete in-stent thrombosis which resolved after intraarterial administration of abciximab and placement of a new stent in-stent. Of the 20 patients treated with stent deployment, a follow-up imaging study was available in all 19 surviving patients (95%) at an average of 16.2 months (range, 6 to 50 months). The first follow-up DSA, compared with initial angiography, showed no changes in 14 aneurysms (73.7%), progressive thrombosis in 3 (15.7%), and major recurrence in 2 (10.5%). The overall rate of succesful procedure to 6 months is 89.5%; there was 1 case of asintomatic moderate endothelial hyperplasia. The further follow-up imaging study, showed no changes in 17 (89.5%) of the 19 surviving patients, 1 progressive thrombosis and 1 minor recurrence. One month- and long term (average of 16.2 months; range, 6 to 50 months) clinical follow-up showed no worsening in the mRS in 18 (90%) of 20 patients, 1 (5%) mRS 2 and 1 (5%) mRS 6. All the survived patients are alive and we did not observe periprocedural or long-term intracranial bleeding events or symptomatic stent related stenosis/occlusion complication. Conclusions: Our findings suggest that the endovascular treatment of intracranial aneurysms by stenting is feasible, effective and safe; follow-up results proved intact parent arteries and stable occlusion rates in the majority of treated aneurysms. Nevertheless, long-term data on safety and efficacy and larger patient groups are necessary

In vivo visualization and analysis of 3-D hemodynamics in cerebral aneurysms with flow-sensitized 4-D MR imaging at 3T

Introduction: Blood-flow patterns and wall shear stress (WSS) are considered to play a major role in the development and rupture of cerebral aneurysms. These hemodynamic aspects have been extensively studied in vitro using geometric realistic aneurysm models. The purpose of this study was to evaluate the feasibility of in vivo flow-sensitized 4-D MR imaging for analysis of intraaneurysmal hemodynamics. Methods: Five cerebral aneurysms were examined using ECG-gated, flow-sensitized 4-D MR imaging at 3T in three patients. Postprocessing included quantification of flow velocities, visualization of time-resolved 2-D vector graphs and 3-D particle traces, vortical flow analysis, and estimation of WSS. Flow patterns were analyzed in relation to aneurysm geometry and aspect ratio. Results: Magnitude, spatial and temporal evolution of vortical flow differed markedly among the aneurysms. Particularly unstable vortical flow was demonstrated in a wide-necked parophthalmic ICA aneurysm (high aspect ratio). Relatively stable vortical flow was observed in aneurysms with a lower aspect ratio. Except for a wide-necked cavernous ICA aneurysm (low aspect ratio), WSS was reduced in all aneurysms and showed a high spatial variation. Conclusion: In vivo flow-sensitized 4-D MR imaging can be applied to analyze complex patterns of intraaneurysmal flow. Flow patterns, distribution of flow velocities, and WSS seem to be determined by the vascular geometry of the aneurysm. Temporal and spatial averaging effects are drawbacks of the MR-based analysis of flow patterns as well as the estimation of WSS, particularly in small aneurysms. Further studies are needed to establish a direct link between definitive flow patterns and different aneurysm geometrie

Classification of Human Retinal Microaneurysms Using Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography

Purpose. Microaneurysms (MAs) are considered a hallmark of retinal vascular disease, yet what little is known about them is mostly based upon histology, not clinical observation. Here, we use the recently developed adaptive optics scanning light ophthalmoscope (AOSLO) fluorescein angiography (FA) to image human MAs in vivo and to expand on previously described MA morphologic classification schemes. Methods. Patients with vascular retinopathies (diabetic, hypertensive, and branch and central retinal vein occlusion) were imaged with reflectance AOSLO and AOSLO FA. Ninety-three MAs, from 14 eyes, were imaged and classified according to appearance into six morphologic groups: focal bulge, saccular, fusiform, mixed, pedunculated, and irregular. The MA perimeter, area, and feret maximum and minimum were correlated to morphology and retinal pathology. Select MAs were imaged longitudinally in two eyes. Results. Adaptive optics scanning light ophthalmoscope fluorescein angiography imaging revealed microscopic features of MAs not appreciated on conventional images. Saccular MAs were most prevalent (47%). No association was found between the type of retinal pathology and MA morphology (P = 0.44). Pedunculated and irregular MAs were among the largest MAs with average areas of 4188 and 4116 μm2, respectively. Focal hypofluorescent regions were noted in 30% of MAs and were more likely to be associated with larger MAs (3086 vs. 1448 μm2, P = 0.0001). Conclusions. Retinal MAs can be classified in vivo into six different morphologic types, according to the geometry of their two-dimensional (2D) en face view. Adaptive optics scanning light ophthalmoscope fluorescein angiography imaging of MAs offers the possibility of studying microvascular change on a histologic scale, which may help our understanding of disease progression and treatment response

Carotid Intern Aneurysms

Cerebral aneurysms (CA) are acquired lesions, affecting 5–10% of the population, being about three times more common in women than in men. The absolute majority of CA is asymptomatic. However, in symptomatic cases, cerebral aneurysms present without about 80% of cases with severe intracranial hemorrhage, with mortality up to 50% and severe morbidity of up to 80%. At this point, the carotid siphon is particularly important because it is the blood gateway to the anterior cerebral circulation, being the most sinuous portion of the internal carotid artery, and because it houses about 30% of the intracranial aneurysm. The constant interactions of blood flow with carotid siphon curvatures are apparently intrinsically related to the epidemiology of these lesions in the various locations of the intracranial circulation and their presentation form. It is well established that a greater anterior knee angle has a significant independent relation with intracranial aneurysms located after carotid siphon, larger aneurysms, and greater risk of rupture. These findings may be associated with the hemodynamic interactions of blood flow and the curvature of carotid siphon. Little is known about the anatomical changes in carotid siphon and, consequently, the repercussions of the hemodynamic changes that the neurosurgical interventions mechanisms could entail. Devices such as intracranial stents, detachable coils, and even clips of aneurysms can modify the morphology of carotid siphon, and the knowledge of these consequences could be used to obtain better therapeutic results. In the last 10 years, a new device for the treatment of intracranial aneurysms has been presenting promising results, flow diverters stents (FDS), and its use to treat aneurysms in carotid siphon appears to cause morphological changes characterized by increased anterior and posterior angles. Specifically, the anterior angle increase was associated with better angiographic results. Aneurysms of the extracranial carotid artery (ECAA) are rare and little is known about its natural history. The etiology is diverse and most ECAA are asymptomatic, but they may progress to a pulsatile mass, cranial nerve compression, or cause a stroke. ECAA treatment is still controversial and a better insight into natural history and risk of complications of the different treatments is needed in order to get the consensus

Comparison of existing aneurysm models and their path forward

The two most important aneurysm types are cerebral aneurysms (CA) and abdominal aortic aneurysms (AAA), accounting together for over 80\% of all fatal aneurysm incidences. To minimise aneurysm related deaths, clinicians require various tools to accurately estimate its rupture risk. For both aneurysm types, the current state-of-the-art tools to evaluate rupture risk are identified and evaluated in terms of clinical applicability. We perform a comprehensive literature review, using the Web of Science database. Identified records (3127) are clustered by modelling approach and aneurysm location in a meta-analysis to quantify scientific relevance and to extract modelling patterns and further assessed according to PRISMA guidelines (179 full text screens). Beside general differences and similarities of CA and AAA, we identify and systematically evaluate four major modelling approaches on aneurysm rupture risk: finite element analysis and computational fluid dynamics as deterministic approaches and machine learning and assessment-tools and dimensionless parameters as stochastic approaches. The latter score highest in the evaluation for their potential as clinical applications for rupture prediction, due to readiness level and user friendliness. Deterministic approaches are less likely to be applied in a clinical environment because of their high model complexity. Because deterministic approaches consider underlying mechanism for aneurysm rupture, they have improved capability to account for unusual patient-specific characteristics, compared to stochastic approaches. We show that an increased interdisciplinary exchange between specialists can boost comprehension of this disease to design tools for a clinical environment. By combining deterministic and stochastic models, advantages of both approaches can improve accessibility for clinicians and prediction quality for rupture risk.Comment: 46 pages, 5 figure

A framework for intracranial saccular aneurysm detection and quantification using morphological analysis of cerebral angiograms

Reliable early prediction of aneurysm rupture can greatly help neurosurgeons to treat aneurysms at the right time, thus saving lives as well as providing significant cost reduction. Most of the research efforts in this respect involve statistical analysis of collected data or simulation of hemodynamic factors to predict the risk of aneurysmal rupture. Whereas, morphological analysis of cerebral angiogram images for locating and estimating unruptured aneurysms is rarely considered. Since digital subtraction angiography (DSA) is regarded as a standard test by the American Stroke Association and American College of Radiology for identification of aneurysm, this paper aims to perform morphological analysis of DSA to accurately detect saccular aneurysms, precisely determine their sizes, and estimate the probability of their ruptures. The proposed diagnostic framework, intracranial saccular aneurysm detection and quantification, first extracts cerebrovascular structures by denoising angiogram images and delineates regions of interest (ROIs) by using watershed segmentation and distance transformation. Then, it identifies saccular aneurysms among segmented ROIs using multilayer perceptron neural network trained upon robust Haralick texture features, and finally quantifies aneurysm rupture by geometrical analysis of identified aneurysmic ROI. De-identified data set of 59 angiograms is used to evaluate the performance of algorithms for aneurysm detection and risk of rupture quantification. The proposed framework achieves high accuracy of 98% and 86% for aneurysm classification and quantification, respectively