Combination of Morphological and Hemodynamic Parameters for Assessing the Rupture Risk of Intracranial Aneurysms: A Retrospective Study on Mirror Middle Cerebral Artery Aneurysms.

Discordant findings were frequently reported by studies dedicated to exploring the association of morphological/hemodynamic factors with the rupture of intracranial aneurysms (IAs), probably owing to insufficient control of confounding factors. In this study, we aimed to minimize the influences of confounding factors by focusing IAs of interest on mirror aneurysms and, meanwhile, modeling IAs together with the cerebral arterial network to improve the physiological fidelity of hemodynamic simulation. Fifty-two mirror aneurysms located at the middle cerebral artery (MCA) in 26 patients were retrospectively investigated. Numerical tests performed on two randomly selected patients demonstrated that over truncation of cerebral arteries proximal to the MCA during image-based model reconstruction led to uncertain changes in computed values of intra-aneurysmal hemodynamic parameters, which justified the minimal truncation strategy adopted in our study. Five morphological parameters (i.e., volume (V), height (H), dome area (DA), nonsphericity index (NSI), and size ratio (SR)) and two hemodynamic parameters (i.e., peak wall shear stress (WSS) (peakWSS), and pressure loss coefficient (PLc)) were found to differ significantly between the ruptured and unruptured aneurysms and proved by receiver operating characteristic (ROC) analysis to have potential value for differentiating the rupture status of aneurysm with the areas under curve (AUCs) ranging from 0.681 to 0.763. Integrating V, SR, peakWSS, and PLc or some of them into regression models considerably improved the classification of aneurysms, elevating AUC up to 0.864, which indicates that morphological and hemodynamic parameters have complementary roles in assessing the risk of aneurysm rupture.

Hemodynamic and Morphological Parameters of Ruptured Mirror Posterior Communicating Artery Aneurysms.

Objective: Morphological and hemodynamic parameters might predict rupture of intracranial aneurysms (IAs). A practical model for the study is patients with ruptured mirror IAs in which one is ruptured and the other is unruptured. Although there have been analyses of the morphology and hemodynamics of ruptured mirror posterior communicating artery aneurysms (PComAAs), the sample sizes in these studies were small and only considered hemodynamics or morphological characters. Therefore, this study aimed to investigate the morphological and hemodynamic parameters associated with ruptured mirror PComAAs. Methods: We considered 72 patients with ruptured mirror PComAAs using computational fluid dynamics (CFDs). Ruptured mirror PComAAs were divided into ruptured and unruptured groups. Fourteen morphological and eight hemodynamic parameters were calculated and compared. Significant parameters were analyzed by the multivariate logistic regression to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for all independent risk factors to determine the predictability and identify the optimal threshold. Results: Four hemodynamic and three morphological parameters were significantly different between ruptured and unruptured groups: normalized wall shear stress (NWSS), mean WSS, low wall shear WSS area (LSA%), size, aspect ratio (AR), size ratio (SR), and inflow angle (IA). Multivariate logistic regression analysis showed that AR, SR, NWSS, mean WSS, and LSA% were all independent factors significantly associated with PComAAs rupture. The ROC analysis for independent risk factors indicated that AR (0.751), NWSS (0.755), mean WSS (0.69), and LSA (0.778) had merely acceptable AUC values. Only SR (0.803) had a high acceptable AUC value. The threshold value of SR was 1.96. Conclusions: SR (>1.96) was the most significant parameter associated with IA rupture, whereas AR, NWSS, mean WSS, and LSA independently characterized the status of IA rupture.

Morphological and Hemodynamic Characteristics Associated With the Rupture of Multiple Intracranial Aneurysms.

BACKGROUND AND PURPOSE: The objective of this study was to identify the morphological and hemodynamic factors associated with the rupture of multiple intracranial aneurysms regardless of patient-related factors and establish a statistical model for aneurysm rupture risk assessment. METHODS: The digital subtraction angiography (DSA) data of 104 mirror intracranial aneurysms in 52 consecutive patients were retrospectively analyzed in this study. 21 morphological parameters and hemodynamic parameters were calculated by 3-dimensional reconstruction and computational fluid dynamics (CFD) simulation. Significant differences (p < 0.05) between the two groups were subsequently tested with the multivariate logistic regression to identify the independent risk factors. A prediction model was established based on the independent risk factors. The receiver operating characteristics (ROCs) were generated to estimate the prediction performance. A cohort of patients with multiple intracranial aneurysms admitted in our institute from January 2021 to October 2021 was introduced to verify the value of the model. RESULTS: Significant differences between the ruptured and unruptured aneurysms were found in 15 out of 19 parameters. Bleb formation, neck width, and size ratio were independent factors in the multivariate logistic regression. A prediction model based on the three independent risk factors was established: Odds = -1.495 - 0.707 × (Neckwidth) + 3.061 × (Blebformation) + 2.1 × (SR) (bleb formation: Yes = 1, No = 0). The area under the curve (AUC) value of the model was 0.901. In the validation cohort, the prediction model showed satisfying performance in assessing multiple aneurysm rupture risk with a sensitivity of 100% and specificity of 88.46%. CONCLUSION: Bleb formation, neck width, and size ratio were independently associated with aneurysm rupture status. The prediction model may help in identifying the aneurysm with high rupture risk.

Hemodynamic and Morphological Analysis of Mirror Aneurysms Prior to Rupture.

OBJECTIVE: Hemodynamic factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. Previous hemodynamic studies have been based on comparisons between post-ruptured and unruptured aneurysms. Nevertheless, changes of aneurysm morphology after rupture render these results unreliable. Moreover, pressure, age, gender, and the morphology of the parent artery also influence these results. Therefore, in the present study, we identified hemodynamic and morphological characteristics of aneurysms prior to rupture using twelve mirror aneurysms. MATERIALS AND METHODS: From our database, we retrospectively analyzed twelve mirror aneurysms (MANs) prior to rupture. Each mirror aneurysm was divided into the prior to rupture or the unruptured group. Patient-specific models were reconstructed from three-dimensional (3D) images of all patients. Hemodynamic and morphological factors were analyzed and compared. RESULTS: Compared with the unruptured side of MANs, aneurysms prior to rupture were significantly larger and significantly more irregular in shape; they also had significantly higher aspect ratio (AR), size ratio (SR), undulation index (UI), ellipticity index (EI), percentage of low wall shear stress area (LSA) and significantly lower normal wall shear stress (NWSS). The oscillatory shear index (OSI) and nonsphericity index (NSI) in the aneurysms prior to rupture were non-significantly higher than those of the unruptured group. CONCLUSION: MANs prior to rupture may be extremely useful models to assess the risk of aneurysm rupture. Larger size, irregular shape, higher AR, SR, UI, NI, and lower WSS may be associated with aneurysms at risk for rupture.

Multiples of multiple: Case series of mirror aneurysms and review of literature.

INTRODUCTION: Mirror aneurysms are a rare subtype of multiple aneurysms, located in identical or adjacent arterial segment bilaterally. We report a case series of 3 such patients amongst whom one of them had 3 sets of mirror aneurysms and the other patient had 2 sets of mirror aneurysm on the same arterial segment which has not been reported till date. METHODS: A retrospective analysis of 3 patients with incidentally detected multiple mirror aneurysms, who were treated with microsurgical clipping and coiling, was conducted. A systematic search was performed using the PUBMED database and relevant articles were reviewed with particular attention to incidence, associated conditions, risk factors and management strategies. Written informed consent was obtained from all of the patients for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request. This research work has been reported in line with the PROCESS criteria (Agha et al., 2018). RESULTS: All the 3 patients were females with incidentally detected multiple mirror aneurysms. All the 3 patients were known Hypertensives. All the aneurysms were successfully clipped by a multistage, bilateral craniotomy except the one in the cavernous ICA, for which an endovascular procedure is planned. All of them had an uneventful postoperative course with the CT angiogram showing obliteration of all the clipped aneurysms except the one in the cavernous ICA. CONCLUSIONS: Multiple mirror aneurysms represent a rare occurrence of a diverse pathology. Both these described types of cases have not been reported so far in the literature. The treatment strategy for mirror aneurysms should be determined individually based on the location, size, and morphology of the aneurysms, as well as, on the clinical manifestations of each patient.

Intracranial Mirror Aneurysm: Epidemiology, Rupture Risk, New Imaging, Controversies, and Treatment Strategies.

There are some controversies about the surgical treatment strategy of mirror aneurysms. Whether to choose 1-stage or 2-stage surgery, bilateral or unilateral craniotomy, or surgical or interventional treatment are the main points in dispute. In this review, the different surgery strategies faced by patients are discussed. Different surgical methods are adopted based on the patient's individual state and the location and size of the aneurysm. A new imaging method is introduced using 3D Slicer, which clearly recognizes the relationship among aneurysm, brain tissue, skull, and nerve. The 3D Slicer can help surgeons undertake adequate preoperative preparation. In addition, we also introduce some ruptured factors (e.g., age, gender, hypertension, morphologic, and hemodynamic) concerning mirror aneurysm. Systematic discussion of the controversies and methods in surgical treatment of mirror aneurysms may provide new perspectives in future research for the prevention and treatment of mirror aneurysms.

Mirror Distal Anterior Cerebral Artery Aneurysms in a Patient with Subarachnoid Hemorrhage.

BACKGROUND: Mirror distal anterior cerebral artery aneurysms (DACAAs) are a rare finding in patients with subarachnoid hemorrhage, with only a few cases reported. CASE DESCRIPTION: A 40-year-old man was admitted for sudden-onset headache, nausea and vomiting, and transient right arm hypoesthesia. Computed tomography scan showed a subarachnoid hemorrhage with intracerebral hemorrhage within the interhemispheric fissure, but computed tomography angiography failed to identify any aneurysms. Subsequent digital subtraction angiography with three-dimensional reconstructions revealed 1.5-mm-diameter mirror DACAAs on the A3 segments. However, the definite rupture site remained unidentifiable. After interdisciplinary consultation, endovascular treatment was favored, and complete occlusion of both DACAAs was achieved by coiling without stent placement. During coiling of the right DACAA, a thrombus in the right callosomarginal artery formed, and treatment with abciximab (ReoPro) was initiated to dissolve the thrombus. After treatment, the patient presented with right leg paresis; however, computed tomography did not show any ischemia, intracerebral hemorrhage increase, or vasospasm. Over the following days, the leg paresis improved, and the patient achieved increased mobilization. He was transferred for further rehabilitation 16 days after hemorrhage. The leg paresis had recovered to a grade 3/5. CONCLUSIONS: Rapid identification of the rupture site in patients with subarachnoid hemorrhage and multiple aneurysms is crucial for initiating optimal treatment. In patients with mirror aneurysms in close proximity to each other, this is not easily accomplished, complicating treatment decisions. Although clipping has been the standard for DACAA occlusion, coiling should be taken into consideration as a viable alternative.

Treatment Strategies for Intracranial Mirror Aneurysms.

OBJECTIVE: Intracranial mirror aneurysms are clinically rare and uncommonly reported in the literature. Therefore, the present study evaluated a series of mirror aneurysm cases with respect to the clinical features of the patients and the treatment strategies that were used. METHODS: This study retrospectively reviewed and systematically analyzed the clinical features, imaging data, treatment methods, and treatment outcomes of 68 cases of mirror aneurysms (a total of 70 pairs) in patients who were admitted to our department between November 2007 and May 2016. RESULTS: The patient population included 24 male and 44 female patients, with a mean age of 52 years. The mirror aneurysms were primarily located in posterior communicating artery and middle cerebral artery and 65 of the aneurysms were large or giant (≧10 mm). Of the 68 patients, 28 were treated by the clipping or embolization of all aneurysms in one stage, 16 were treated in 2 stages, 16 were treated by treating part of the aneurysms, and 8 were observed. The modified Rankin Scale scores of the 60 patients that were treated indicated that 52 had a good recovery (modified Rankin Scale score ≦2; 86.7%), and 1 patient died. CONCLUSIONS: Treatment strategies for mirror aneurysms should be determined individually according to the location, size, and morphology of the aneurysm, as well as the clinical manifestations of each patient. Furthermore, the responsible ruptured aneurysm should be given treatment priority, whereas the contralateral unruptured aneurysm should be observed or treated in either 1 or 2 stages.

Seven Cerebral Aneurysms: A Challenging Case from the Andean Slopes Managed with 1-Stage Surgery.

BACKGROUND: Treatment of multiple intracranial aneurysms is particularly demanding and even more so in a developing country where access to specialized centers may be prevented by different factors. METHODS: Single-stage surgical treatment of 7 cerebral aneurysms was performed in a 58-year-old woman from the northern Peruvian Andes. RESULTS: All 7 aneurysms were successfully and safely clipped through 2 lateral supraorbital craniotomies. The double clip technique was used in 3 aneurysms to prevent any residual aneurysmal neck. CONCLUSIONS: Good teamwork and correct application of microsurgical principles may allow effective treatment in complex neurosurgical cases even in resource-challenged environments.

Dreadful Twins: Twin Unruptured Aneurysms of Bilateral Intracranial Arteries.

Intracranial aneurysms are the most common cause of subarachnoid hemorrhage which carries a significant risk of mortality. Mirror aneurysm constitute between 5-12% of all the intracranial aneurysms. These are uncommon entities with poorly understood pathogenesis and clinical significance.