Aneurysm Wall Research Articles

A Case of Posterior Communicating Artery Aneurysm Combined With an Atypical Origin of the Ipsilateral Ophthalmic Artery

Objective: Anatomy of the ophthalmic artery (OA) is of great practical importance in surgery for anterior circulation aneurysms. In most cases, the OA arises from the supraclinoid segment of the internal carotid artery (ICA) and enters the orbit through the optic canal inferolaterally to the optic nerve. The OA arising from the anterior cerebral artery (ACA) and entering the optic canal above the optic nerve is extremely rare.Clinical case: We report a case of a 29-year-old female patient admitted to Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation) with a ruptured true aneurysm of the left posterior communicating artery (PCoA) and an abnormal origin of the OA from the ACA. The disease manifested itself as ischemic stroke in the basal ganglia on the left causing diagnostic difficulties during initial hospitalization. Cerebral angiography confirmed a PCoA aneurysm and origin of the OA from the ipsilateral ACA. During surgery the neck of the aneurysm was clipped, and the aneurysm dome was opened to control the extent of clipping and remove thrombotic masses. During their removal, hemorrhage appeared from the posterior pole of the aneurysm. During the exploration it was found that the aneurysm was a dilated PCoA connecting the right ICA with the right posterior cerebral artery (PCA). A thrombosed anterior thalamoperforating artery emerged from the superior surface of the dome, and its junction with the precommunicating segment of the right PCA was detected in the region of the posterior pole of the aneurysm. The second clip was placed at the communication site between the aneurysm and the right PCA. The patient was discharged in satisfactory condition with a stable neurological status.Conclusions: The combination of abnormal anatomy of arteries at the base of the brain and cerebral aneurysms increases the risk of tactical errors and perioperative complications. Each such case requires a careful comparison of the clinical, imaging, and intraoperative findings. In the presented case of the patient with the ruptured rare PCoA aneurysm, the disease manifested atypically due to the partial thrombosis of the aneurysm and hemorrhage into the aneurysmal wall. The imaging findings revealed lacunar stroke in the thalamoperforating artery basin and an ICA aneurysm with no signs of subarachnoid hemorrhage. During the surgery the aneurysm was initially regarded as typical saccular. The opening of the dome and removal of all thrombotic masses made it possible to determine the eccentric fusiform nature of the aneurysm, perform its radical exclusion, and prevent fatal hemorrhage in the postoperative period.

Low shear stress induces macrophage infiltration and aggravates aneurysm wall inflammation via CCL7/CCR1/TAK1/ NF-κB axis

BackgroundThis study aimed to elucidate the mechanism by which wall shear stress (WSS) influences vascular walls, accounting for the susceptibility of intracranial aneurysms (IAs) to rupture. MethodWe collected blood samples from the sacs of 24 ruptured and 28 unruptured IAs and analyzed the expression of chemokine CCL7 using enzyme-linked immunosorbent assay (ELISA). Univariate and multivariate logistic regression analyses were employed to assess clinical data, aneurysm morphology, and hemodynamics in both groups. Pearson correlation analysis investigated the relationship between CCL7 expression in aneurysm sac blood and WSS. Additionally, we established a bionic cell parallel plate co-culture shear stress model and a mouse low shear stress (LSS) model. The model was modulated using CCL7 recombinant protein, CCR1 inhibitor, and TAK1 inhibitor. We further evaluated CCL7 expression in endothelial cells and the levels of TAK1, NF-κB, IL-1β, and TNF-α in macrophages. Subsequently, the intergroup differences in expression were calculated. ResultsCCL7 expression was significantly higher in the ruptured group compared to the unruptured group. Hemodynamic analysis indicated that WSS was an independent predictor of the risk of aneurysm rupture. A negative linear correlation was observed between CCL7 expression and WSS. Upon addition of CCL7 recombinant protein, upregulation of CCR1 expression and increased levels of p-TAK1 and p-p65 were observed. Treatment with CCR1 and TAK1 inhibitors reduced inflammatory cytokine expression in macrophages under LSS conditions. Overexpression of TAK1 significantly alleviated the inhibitory effects of CCR1 inhibitors on p-p65 and inflammatory cytokines. ConclusionLSS prompts endothelial cells to secrete CCL7, which, upon binding to the macrophage surface receptor CCR1, stimulates the release of macrophage inflammatory factors via the TAK1/NF-κB signaling pathway. This process exacerbates aneurysm wall inflammation and increases the risk of aneurysm rupture.

A Systematic Review and Meta-Analysis of the Pathology Underlying Aneurysm Enhancement on Vessel Wall Imaging.

Intracranial aneurysms are common, but only a minority rupture and cause subarachnoid haemorrhage, presenting a dilemma regarding which to treat. Vessel wall imaging (VWI) is a contrast-enhanced magnetic resonance imaging (MRI) technique used to identify unstable aneurysms. The pathological basis of MR enhancement of aneurysms is the subject of debate. This review synthesises the literature to determine the pathological basis of VWI enhancement. PubMed and Embase searches were performed for studies reporting VWI of intracranial aneurysms and their correlated histological analysis. The risk of bias was assessed. Calculations of interdependence, univariate and multivariate analysis were performed. Of 228 publications identified, 7 met the eligibility criteria. Individual aneurysm data were extracted for 72 out of a total of 81 aneurysms. Univariate analysis showed macrophage markers (CD68 and MPO, p = 0.001 and p = 0.002), endothelial cell markers (CD34 and CD31, p = 0.007 and p = 0.003), glycans (Alcian blue, p = 0.003) and wall thickness (p = 0.030) were positively associated with enhancement. Aneurysm enhancement therefore appears to be associated with inflammatory infiltrate and neovascularisation. However, all these markers are correlated with each other, and the literature is limited in terms of the numbers of aneurysms analysed and the parameters considered. The data are therefore insufficient to determine if these associations are independent of each other or of aneurysm size, wall thickness and rupture status. Thus, the cause of aneurysm-wall enhancement currently remains unknown.

Decoding the Cell Atlas and Inflammatory Features of Human Intracranial Aneurysm Wall by Single-Cell RNA Sequencing.

Intracranial aneurysm (IA) is common and occasionally results in life-threatening hemorrhagic strokes. However, the cell architecture and inflammation in the IA dome remain less understood. Single-cell RNA sequencing was performed on ruptured and unruptured human IA domes for delineating the cell atlas, gene expression perturbations, and inflammation features. Two external bulk mRNA sequencing-based data sets and serological results of 126 patients were collected for validation. As a result, a total of 21 332 qualified cells were captured. Vascular cells, including endothelial cells, smooth muscle cells, fibroblasts, and pericytes, were assigned in extremely sparse numbers (4.84%), and were confirmed by immunofluorescence staining. Pericytes, characterized by ABCC9 and HIGD1B, were identified in the IA dome for the first time. Abundant immune cells were identified, with the proportion of monocytes/macrophages and neutrophils being remarkably higher in ruptured IA. The lymphocyte compartment was also thoroughly categorized. By leveraging external data sets and machine learning algorithms, macrophages were robustly associated with IA rupture, irrespective of their polarization status. The single nucleotide polymorphism rs2280543, which is identified in East Asian populations, was associated with macrophage metabolic reprogramming through regulating TALDO1 expression. This study provides insights into the cellular architecture and inflammatory features in the IA dome and may enlighten novel therapeutics for unruptured IA.

Towards the mechanical characterisation of unruptured intracranial aneurysms: Numerical modelling of interactions between a deformation device and the aneurysm wall

Intracranial aneurysm is a critical pathology related to the arterial wall deterioration. This work is an essential aspect of a large scale project aimed at providing clinicians with a non-invasive patient-specific decision support tool regarding the rupture risk assessment. A machine learning algorithm links the aneurysm shape observed and a database of UIA clinical images associated with in vivo wall mechanical properties and rupture characterisation. The database constitution is derived from a device prototype coupled with medical imaging. It provides the mechanical characterisation of the aneurysm from the wall deformation obtained by inverse analysis based on the variation of luminal volume. Before performing in vivo tests of the device on small animals, a numerical model was built to quantify the device’s impact on the aneurysm wall under natural blood flow conditions. As the clinician will never be able to precisely situate the device, several locations were considered. In preparation for the inverse analysis procedure, artery material laws of increasing complexity were studied (linear elastic, hyper elastic Fung-like).Considering all the device locations and material laws, the device induced relative displacements to the Systole peak (worst case scenario with the highest mechanical stimulus linked to the blood flow) ranging from 375 μm to 1.28 mm. The variation of luminal volume associated with the displacements was between 0.95 % and 4.3 % compared to the initial Systole volume of the aneurysm. Significant increase of the relative displacements and volume variations were found with the study of different cardiac cycle moments between the blood flow alone and the device application. For forthcoming animal model studies, Spectral Photon CT Counting, with a minimum spatial resolution of 250 μm, was selected as the clinical imaging technique. Based on this preliminary study, the displacements and associated volume variations (baseline for inverse analyse), should be observable and exploitable.

Hemodynamic Insights into Abdominal Aortic Aneurysms: Bridging the Knowledge Gap for Improved Patient Care

Background: Abdominal aortic aneurysms (AAAs) present a formidable public health concern due to their propensity for localized, anomalous expansion of the abdominal aorta. These insidious dilations, often in their early stages, mask the life-threatening potential for rupture, which carries a grave prognosis. Understanding the hemodynamic intricacies governing AAAs is paramount for predicting aneurysmal growth and the imminent risk of rupture. Objective: Our extensive investigation delves into this complex hemodynamic environment intrinsic to AAAs, utilizing comprehensive numerical analyses of the physiological pulsatile blood flow and realistic boundary conditions to explore the multifaceted dynamics influencing aneurysm rupture risk. Our study introduces novel elements by integrating these parameters into the overall context of aneurysm pathophysiology, thus advancing our understanding of the intricate mechanics governing their evolution and rupture. Methods: Conservation of mass and momentum equations are used to model the blood flow in an AAAs, and these equations are solved using a finite volume-based ANSYS Fluent solver. Resistance pressure outlets following a three-element Windkessel model were imposed at each outlet to accurately model the blood flow and the AAAs’ shear stress. Results: Our results uncover elevated blood flow velocities within an aneurysm, suggesting an augmented risk of future rupture due to increased stress in the aneurysm wall. During the systole phase, high wall shear stress (WSS) was observed, typically associated with a lower risk of rupture, while a low oscillatory shear index (OSI) was noted, correlating with a decreased risk of aneurysm expansion. Conversely, during the diastole phase, low WSS and a high OSI were identified, potentially weakening the aneurysm wall, thereby promoting expansion and rupture. Conclusion: Our study underscores the indispensable role of computational fluid dynamic (CFD) techniques in the diagnostic, therapeutic, and monitoring realms of AAAs. This body of research significantly advances our understanding of aneurysm pathophysiology, thus offering pivotal insights into the intricate mechanics underpinning their progression and rupture, informing clinical interventions and enhancing patient care.

Intracranial aneurysm wall displacement depicted by amplified Flow predicts growth

BackgroundAbnormal intracranial aneurysm (IA) wall motion has been associated with IA growth and rupture. Recently, a new image processing algorithm called amplified Flow (aFlow) has been used to successfully track...

Abstract TMP1: Cerebral Aneurysm Walls Contain Myoglobin That is Possibly Produced by Myofibroblasts and Contributes to Wall Thickening

Background: Cerebral aneurysms rupture at a thin-walled region; however, mechanisms of aneurysmal wall thinning and thickening remain unclear. Myoglobin scavenges nitric oxide and reactive oxygen spices which promote aneurysmal development. Objectives: To investigate the biological role of myoglobin in aneurysmal wall. Methods: Cerebral aneurysmal wall samples were collected between August 2020 and March 2022 for proteomic analysis and immunohistology. We examined the co-localization of myoglobin expression within smooth muscle cells, identified by α-smooth muscle actin (α-SMA) staining, and myofibroblasts, identified by periostin staining. Collagen and myoglobin density in the same sample areas were investigated for its correlation in the aneurysm walls. Results: A total of 35 specimens were obtained from 21 patients who underwent aneurysmal clipping. Proteome analysis was performed using 11 specimens, which firstly detected myoglobin predominantly in the thickened wall. Among 24 formalin-fixed samples, 19 samples were found myoglobin expression. Myoglobin was mostly scattered within the vascular smooth muscle layer and tended to be expressed at sites where iNOS was scarce. Double-label immunofluorescence staining confirmed that the myoglobin-positive rate within α-SMA-positive cells/areas was 33.2±23.8%/31.3±37.8%, respectively, whereas within periostin-positive cells/areas it was 92.2±13.7%/79.8±29.5, respectively. A total of 32 areas were investigated for the correlation between collagen and myoglobin density , which a strong correlation was observed with a Spearman's rank correlation coefficient of 0.635 (p < 0.001). Conclusions: Cerebral aneurysmal walls express myoglobin, which may be produced by myofibroblasts in the wall. Areas with high myoglobin levels retain high levels of collagen fibers, and myoglobin may be involved in wall thickening by suppressing destructive changes in the extracellular collagen fibers.

Abstract TMP114: The Role of Iron Mediated Oxidative Stress and Lipid Peroxidation in the Development of Intracranial Aneurysm Rupture

Introduction: Iron is an essential element for vascular wall maintenance. However, iron deposition in the vascular wall may cause oxidative stress, which can attack DNA, proteins, and lipid membranes via the Fenton/Haber-Weiss reaction. Iron-induced oxidative stress triggers lipid oxidation, inflammation, endothelial cell activation and intracranial aneurysmal formation, growth, and rupture. Subarachnoid hemorrhage from intracranial aneurysm rupture results in significant morbidity and mortality. This study used a mouse model of intracranial aneurysm to evaluate the effect of dietary iron restriction on aneurysm formation and rupture. Methods: Intracranial aneurysms were induced using deoxycorticosterone acetate-salt-induced hypertension and a single injection of elastase into the cerebrospinal fluid of the basal cistern. Mice were fed an iron-restricted diet or a normal diet. Aneurysm rupture was detected by neurological symptoms, while the presence of intracranial aneurysm with subarachnoid hemorrhage was confirmed by post-mortem examination. Results: The aneurysmal rupture rate was significantly lower in iron-restricted diet mice (37%) compared with normal diet mice (76%; p < 0.05). Serum oxidative stress, iron accumulation, macrophage infiltration, and 8-hydroxy-2′-deoxyguanosine in the vascular wall were lower in iron-restricted diet mice ( p < 0.01). The areas of iron positivity were similar to the areas of CD68 positivity and 8-hydroxy-2′-deoxyguanosine in both normal diet and iron-restricted diet mice aneurysms. Conclusions: Compared with a normal diet, an iron-restricted diet reduced the incidence of intracranial aneurysmal rupture in mice via inhibition of iron accumulation in the aneurysmal wall. Iron may be a potential therapeutic target to prevent intracranial aneurysm rupture. Long-term iron restriction may be required to affect aneurysm formationrupture.

Multimodality magnetic resonance evaluating the effect of enhanced physical exercise on the growth rate, flow haemodynamics, aneurysm wall and ventricular-aortic coupling of patients with small abdominal aortic aneurysms (AAA MOVE trial): a study protocol for an open-label randomised controlled trial

IntroductionThe best lifestyle for small abdominal aortic aneurysms (sAAA) is essential for its conservative management. Physical exercise can improve the cardiopulmonary function of the patients, but it remains unclear which...

Ruptured Saccular Aneurysm Caused by Necrotizing Arteritis of the Polyarteritis Nodosa Type in Primary Angiitis of Central Nervous System.

Primary angiitis of central nervous system (PACNS) is a rare idiopathic vasculitis that typically involves small arteries. An 18-year-old woman was operated on for resection of a ruptured aneurysm in a cerebral artery. Multiple aneurysms of cerebral arteries had been detected by neuroimaging examinations since the age of 12, and she had been administered drugs following a diagnosis of PACNS since the age of 15. The resected aneurysm was a ruptured saccular aneurysm occurring in a medium-sized artery. Histologically, necrotizing arteritis of the polyarteritis nodosa (PAN) type was noted in the aneurysmal wall. It consisted of an admixture of acute and healing stages. In the acute stage, fibrinoid necrosis in the intima and media and intense inflammatory cell infiltrate in the entire wall were present. The inflammatory cells mainly consisted of lymphocytes, including plasma cells, neutrophils, and macrophages. In the healing stage, disappearance of fibrinoid necrosis, fibrosis in the intima and media, and scarce inflammatory cells were noted. The acute stage was mainly present near the ruptured site. From these findings, the aneurysm was considered to have been caused by necrotizing arteritis of the PAN type. Although saccular aneurysmal formation in a medium-sized artery is rare in PACNS, an understanding of aneurysms produced by necrotizing arteritis of the PAN type offers useful information for the diagnosis and treatment of PACNS.

Chinese guideline for the diagnosis and treatment of Takayasu's arteritis(2023)

Takayasu's arteritis (TAK) is a chronic granulomatous inflammatory disease that involves the aorta and its primary branch arteries. It is characterized by wall thickening,stenosis or aneurysm formation of involved arteries,leading to ischemia of related organs. The clinical diagnosis and treatment of TAK is challenging. In order to further improve the level of diagnosis and treatment of TAK in China and standardize the diagnosis and treatment of TAK, a clinical practice guidelines based on evidence-based medicine evidence was developed under the leadership of the National Clinical Medical Research Center for Dermatologic and Immunologic Diseases. Eleven recommendations for 11 clinical questions problems that are important to the diagnosis and treatment of TAK were developed based on the latest research evidence and expert opinions, combined with real clinical practice in China.

Association between intracranial aneurysm wall enhancement and intracranial atherosclerotic plaque: a cross-sectional study using high-resolution vessel wall imaging.

Intracranial aneurysms and intracranial atherosclerosis are prevalent cerebrovascular diseases, and individuals with atherosclerosis have a higher incidence of aneurysms than those without atherosclerosis. However, few studies have conducted combined analyses to investigate the potential association between intracranial aneurysms and intracranial atherosclerosis. This retrospective cross-sectional study aimed to investigate the association between the characteristics of the aneurysm wall and intracranial large arterial plaque using high-resolution vessel wall imaging (HR-VWI). Hospitalized patients diagnosed with anterior circulation unruptured intracranial aneurysms (UIAs), who were diagnosed at Huashan Hospital of Fudan University in Shanghai, China, between March 2016 to February 2018, were consecutively recruited for this study. The patients' pre-treatment HR-VWI images and 3D time-of-flight magnetic resonance angiography (3D-TOF-MRA) images were collected. The patients and UIAs were divided into two groups according to the presence or absence of plaque in the M1 segment of the middle cerebral artery (MCA). Clinical information and aneurysm characteristics were compared between the two groups. Aneurysm wall enhancement (AWE) and M1 plaque were graded on scales of 0 to 2 on HR-VWI. Based on the gradings, the correlation between AWE and the M1 plaques was analyzed. A total of 109 patients with 128 saccular UIAs in the anterior circulation were enrolled in the study. Of the patients, there were 56 patients (with 65 UIAs) in the group with M1 plaque and 53 patients (with 63 UIAs) in the group without plaque. There were significant differences between the two groups in terms of both their clinical information (age and hypertension) and aneurysm characteristics (AWE pattern and AWE degree). The grades of the AWE patterns and the AWE degrees of the UIAs were higher in the group with M1 plaque than in the group without plaque. In the M1 plaque group, the grade of M1 plaque was positively correlated with the grade of AWE pattern (correlation coefficient R=0.41, P=0.001) and the grade of AWE degree (correlation coefficient R=0.50, P<0.001). MCA atherosclerosis plaque was associated with the AWE of saccular aneurysms. When evaluating UIAs, attention should also be paid to the large arterial wall, which may assist in assessing the stability of the aneurysm and enable better decision making.

Abstract TP3: Predicting Rupture Risk of Intracranial Aneurysms Through Radiomics Analysis

Background: Intracranial aneurysm rupture is a devastating event. Accurate estimation of their rupture risk can help guide management decisions. However, existing prediction methods remain subjective and have limited accuracy. This study is aimed at using clinical and imaging data to create an accurate predictive clinical tool for identification of aneurysms at a higher risk of rupturing. Methods: A prospectively acquired database of patients scanned with 3T high-resolution MRI between 2018 to 2023 was analyzed. Symptomatic status was defined as aneurysms that caused a cranial nerve neuropathy due to compression, and/or presented with a sentinel headache. Saccular aneurysms were segmented within 3D Slicer using co-registered T1 and T1+Gd 3T images. Morphological and aneurysm wall enhancement (AWE) metrics were obtained from the 3D models. Radiomic features (RFs) were extracted using pyRadiomics extension of 3D Slicer. This database was utilized for training and testing different machine learning prediction models. Finally, a Naïve bayes model was then employed for constructing clinical nomograms (Figure). Results: A total of one hundred and four aneurysms were analyzed. Twenty-nine were symptomatic. There were 87 RFs significantly different between symptomatic and asymptomatic aneurysms. Four machine learning prediction models were created based on clinical, morphological, AWE and RFs data. The best predictive model was based on RFs, achieving an accuracy of 74%. Conclusion: RFs combined with clinical, morphological and AWE metrics could potentially be a valuable clinical tool to predict intracranial aneurysms rupture risk.

Computational Study of Abdominal Aortic Aneurysm Walls Accounting for Patient-Specific Non-Uniform Intraluminal Thrombus Thickness and Distinct Material Models: A Pre- and Post-Rupture Case.

An intraluminal thrombus (ILT) is present in the majority of abdominal aortic aneurysms, playing a crucial role in their growth and rupture. Although most computational studies do not include the ILT, in the present study, this is taken into account, laying out the whole simulation procedure, namely, from computed tomography scans to medical image segmentation, geometry reconstruction, mesh generation, biomaterial modeling, finite element analysis, and post-processing, all carried out in open software. By processing the tomography scans of a patient's aneurysm before and after rupture, digital twins are reconstructed assuming a uniform aortic wall thickness. The ILT and the aortic wall are assigned different biomaterial models; namely, the first is modeled as an isotropic linear elastic material, and the second is modeled as the Mooney-Rivlin hyperelastic material as well as the transversely isotropic hyperelastic Holzapfel-Gasser-Ogden nonlinear material. The implementation of the latter requires the designation of local Cartesian coordinate systems in the aortic wall, suitably oriented in space, for the proper orientation of the collagen fibers. The composite aneurysm geometries (ILT and aortic wall structures) are loaded with normal and hypertensive static intraluminal pressure. Based on the calculated stress and strain distributions, ILT seems to be protecting the aneurysm from a structural point of view, as the highest stresses appear in the thrombus-free areas of the aneurysmal wall.

Hemodynamic study on the therapeutic effects of varying diameter embolic coils in the treatment of intracranial aneurysms.

Endovascular coiling is the predominant method for treating cerebral aneurysms. Extensive reports on selecting coil length, hardness, and material are available. However, the impact of coil diameter on postoperative outcomes remains unclear. This study enrolled six personalized geometric models of intracranial aneurysms: three bifurcation aneurysms and three sidewall aneurysms. Four coil models were constructed by changing the coil diameter. Coil embolization was simulated using the finite element method. Computational fluid dynamics was used to characterize hemodynamics in the aneurysms after embolization. Evaluation parameters included velocity reduction, wall shear stress (WSS), low WSS (LWSS), oscillatory shear index (OSI), relative residence time (RRT), and residual flow volume in the aneurysms. At the peak time (t = 0.17 s), the proportion of LWSS area in bifurcation aneurysms increase with the rise in coil diameter: 0.8D, 71.28 ± 12.62% versus 1D, 74.97 ± 19.17% versus 1.2D, 78.88 ± 18.56% versus 1.4D, 84.00 ± 11.53% (mean ± SD). The proportion of high OSI area decreases as the coil diameter increases: 0.8D, 4.41% ± 2.82% versus 1.0D, 3.78 ± 3.33% versus 1.2D, 2.28% ± 1.77% versus 1.4D, 1.58% ± 1.11% (mean ± SD). The proportion of high RRT area increases as the coil diameter rises: 0.8D, 3.40% ± 1.68% versus 1.0D, 7.67 ± 4.12% versus 1.2D, 9.84% ± 9.50% versus 1.4D, 22.29% ± 14.28% (mean ± SD). Side wall aneurysms do not exhibit the aforementioned trend. Bifurcation aneurysms plugged with a coil of 1.4 times the diameter have the largest RFVs (<10 mm/s) within the group. Aforementioned patterns are not found in sidewall aneurysms. In the treatment of aneurysms with coiling, varying coil diameters can result in different hemodynamic environments within the aneurysm. Larger coil diameters have improved hemodynamic performance for bifurcation aneurysms. However, coil diameter and embolization effectiveness have no significant relationship for sidewall aneurysms.

Aneurysm healing following treatment with biodegradable embolization materials: assessment in a rat sidewall aneurysm model

BackgroundBiodegradable materials that dissolve after aneurysm healing are promising techniques in the field of neurointerventional surgery. We investigated the effects of various bioabsorable materials in combination with degradable magnesium alloy...

Wall permeability on magnetic resonance imaging is associated with intracranial aneurysm symptoms and wall enhancement.

Wall remodeling and inflammation accompany symptomatic unruptured intracranial aneurysms (UIAs). The volume transfer constant (Ktrans) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) reflects UIA wall permeability. Aneurysmal wall enhancement (AWE) on vessel wall MRI (VWI) is associated with inflammation. We hypothesized that Ktrans is related to symptomatic UIAs and AWE. Consecutive patients with UIAs were prospectively recruited for 3-T DCE-MRI and VWI from January 2018 to March 2023. UIAs were classified as asymptomatic and symptomatic if associated with sentinel headache or oculomotor nerve palsy. Ktrans and AWE were assessed on DCE-MRI and VWI, respectively. AWE was evaluated using the AWE pattern and wall enhancement index (WEI). Spearman's correlation coefficient and univariate and multivariate analyses were used to assess correlations between parameters. We enrolled 82 patients with 100 UIAs (28 symptomatic and 72 asymptomatic). The median Ktrans (2.1 versus 0.4min-1; p < 0.001) and WEI (1.5 versus 0.4; p < 0.001) were higher for symptomatic aneurysms than for asymptomatic aneurysms. Ktrans (odds ratio [OR]: 1.60, 95% confidence interval [95% CI]: 1.01-2.52; p = 0.04) and WEI (OR: 3.31, 95% CI: 1.05-10.42; p = 0.04) were independent risk factors for symptomatic aneurysms. Ktrans was positively correlated with WEI (Spearman's coefficient of rank correlation (rs) = 0.41, p < 0.001). The combination of Ktrans and WEI achieved an area under the curve of 0.81 for differentiating symptomatic from asymptomatic aneurysms. Ktrans may be correlated with symptomatic aneurysms and AWE. Ktrans and WEI may provide an additional value than the PHASES score for risk stratification of UIAs. The volume transfer constant (Ktrans) from DCE-MRI perfusion is associated with symptomatic aneurysms and provides additional value above the clinical PHASES score for risk stratification of intracranial aneurysms. • The volume transfer constant is correlated with intracranial aneurysm symptoms and aneurysmal wall enhancement. • Dynamic contrast-enhanced and vessel wall MRI facilitates understanding of the pathophysiological characteristics of intracranial aneurysm walls. • The volume transfer constant and wall enhancement index perform better than the traditional PHASES score in differentiating symptomatic aneurysms.

Aneurysm Wall Contrast on Magnetic Resonance Imaging: A New Predictor of Rupture of Saccular Intracranial Aneurysms

Background. Recent studies suggest that accumulation of contrast agent in the aneurysm’s wall may predict a high risk of aneurysm growth or rupture.Objective. To compare the enhancement of the aneurysm wall with other characteristics that affect at the risk of rupture.Materials and Methods. The study included 95 patients with 132 previously identified saccular aneurysms, who underwent magnetic resonance imaging (MRI) according to a specialized protocol using 3.0 Tesla MRI scanner. The presence or absence of aneurysm’s wall enhancement compared with the following characteristics: gender and age of the patient, the size and shape of the aneurysm, the presence of arterial hypertension, and the PHASES score.Results. Accumulation of contrast agent by the aneurysm’s wall was associated with the aneurysm dome size (p &lt; 0,001, Sp = 78,1 %, Se = 72,1 %) and PHASES score (p &lt; 0,001, Sp = 64,1 %, Se =57,1 %). No relationship between age, gender, arterial hypertension, shape, and aneurysm location and contrast enhancement was found (p &gt; 0,05).Conclusion. Contrast enhancement of the aneurysm wall on MRI can be considered an additional risk marker of its rupture.

Time-of-flight and black-blood MRI to study intracranial arteries in rats

Intracranial aneurysms (IAs) are usually incidentally discovered by magnetic resonance imaging (MRI). Once discovered, the risk associated with their treatment must be balanced with the risk of an unexpected rupture. Although clinical observations suggest that the detection of contrast agent in the aneurysm wall using a double-inversion recovery black-blood (BB) sequence may point to IA wall instability, the exact meaning of this observation is not understood. Validation of reliable diagnostic markers of IA (in)stability is of utmost importance to deciding whether to treat or not an IA. To longitudinally investigate IA progression and enhance our understanding of this devastating disease, animal models are of great help. The aim of our study was to improve a three-dimensional (3D)-time-of-flight (TOF) sequence and to develop a BB sequence on a standard preclinical 3-T MRI unit to investigate intracranial arterial diseases in rats. We showed that our 3D-TOF sequence allows reliable measurements of intracranial artery diameters, inter-artery distances, and angles between arteries and that our BB sequence enables us to visualize intracranial arteries. We report the first BB-MRI sequence to visualize intracranial arteries in rats using a preclinical 3-T MRI unit. This sequence could be useful for a large community of researchers working on intracranial arterial diseases.Relevance statement We developed a black-blood MRI sequence to study vessel wall enhancement in rats with possible application to understanding IAs instability and finding reliable markers for clinical decision-making.Key points• Reliable markers of aneurysm stability are needed for clinical decision.• Detection of contrast enhancement in the aneurysm wall may be associated with instability.• We developed a black-blood MRI sequence in rats to be used to study vessel wall enhancement of IAs.Graphical