Fusiform aneurysms of the vertebrobasilar complex: a single-center series

Treatment strategies and outcomes for intracranial fusiform aneurysms: A systematic review and meta-analysis

BACKGROUND

Fusiform aneurysms are a distinct subgroup of intracranial aneurysms with unique characteristics and pose a treatment challenge compared to common saccular aneurysms. Traditionally, surgery was the main treatment; however, endovascular techniques are gaining favor.

METHODS

We searched major databases for studies on treatment, clinical outcomes, and radiological outcomes of intracranial fusiform aneurysms published before May 31st, 2023 in order to compare surgical Vs endovascular treatment strategies. Pooled data analysis was performed using a random-effects model.

RESULTS

This systematic review and meta-analysis analyzed 1704 patients with 1737 fusiform aneurysms from 63 studies. Endovascular treatment, particularly stent-assisted coiling and stenting, emerged as the preferred approach with lower mortality and complication rates compared to surgery. Aneurysm location played a role in outcomes, with anterior circulation aneurysms generally faring better. Deconstructive strategies, designed to occlude the parent artery, carried a doubled risk of complications compared to reconstructive approaches, which aim to preserve blood flow (OR: 2.188; 95% CI: 1.474-3.248; p < 0.001).

CONCLUSION

Endovascular techniques are becoming the mainstay of treatment for fusiform aneurysms, offering improved safety and efficacy compared to surgery. Anterior circulation location and reconstructive strategies are associated with better outcomes. However, no significant differences in OR for early complete occlusion were found between surgery and endovascular techniques at discharge and follow-up with very low heterogeneity among studies.

Prognostic Factors in Patients with Unruptured Vertebral and Basilar Fusiform Aneurysms Treated with Endovascular Procedures : A Single Center Retrospective Analysis

PURPOSE

Large vertebral and basilar fusiform aneurysms (VFA) are sometimes difficult to cure by endovascular treatment (EVT). We aimed to elucidate indicators of poor outcomes of EVT in patients with VFAs.

METHODS

Clinical data from 48 patients with 48 unruptured VFAs in the Hyogo Medical University were retrospectively analyzed. The primary outcome was defined as satisfactory aneurysm occlusion (SAO) according to Raymond-Roy grading scale. The secondary and safety outcomes were a modified Rankin scale (mRS) score of 0-2 at 90 days, retreatment, major stroke, and aneurysm-related death after EVT.

RESULTS

The EVT included stent-assisted coiling (n = 24; 50%), flow diverter (n = 19; 40%), and parent artery occlusion (n = 5; 10%). The SAO was less frequently observed in large or thrombosed VFAs at 12 months (64%, p = 0.021 and 62%, p = 0.014, respectively), especially when the aneurysms were both large and thrombosed (50%, p = 0.0030). Retreatment was more common in large aneurysms (29%, p = 0.034), thrombosed (32%, p = 0.011), and large thrombosed aneurysms (38%, p = 0.0036). Although the proportion of mRS 0-2 at 90 days and major stroke showed no significant differences, that of post-treatment rupture was significantly larger in large thrombosed VFAs (19%, p = 0.032). Aneurysm-related death occurred by aneurysm rupture and was more frequent in large thrombosed VFA (19%, p = 0.032). Multivariate analysis showed SAO at 12 months was less common (adjusted odds ratio, OR: 0.036, 95% confidence interval, CI 0.00091-0.57; p = 0.018), and retreatment was more common (adjusted OR 43, 95% CI 4.0-1381; p = 0.0012) in large thrombosed VFA.

CONCLUSION

The large thrombosed VFAs were associated with poor outcomes after EVT including flow diverter.

Comparisons between cross-section and long-axis-section in the quantification of aneurysmal wall enhancement of fusiform intracranial aneurysms in identifying aneurysmal symptoms

Background

To investigate the quantification of aneurysmal wall enhancement (AWE) in fusiform intracranial aneurysms (FIAs) and to compare AWE parameters based on different sections of FIAs in identifying aneurysm symptoms.

Methods

Consecutive patients were prospectively recruited from February 2017 to November 2019. Aneurysm-related symptoms were defined as sentinel headache and oculomotor nerve palsy. All patients underwent high resolution magnetic resonance imaging (HR-MRI) protocol, including both pre and post-contrast imaging. CR_stalk (signal intensity of FIAs' wall divided by pituitary infundibulum) was evaluated both in the cross-section (CR_{stalk−cross}) and the long-axis section (CR_stalk−long) of FIAs. Aneurysm characteristics include the maximal diameter of the cross-section (D_max), the maximal length of the long-axis section (L_max), location, type, and mural thrombus. The performance of parameters for differentiating symptomatic and asymptomatic FIAs was obtained and compared by a receiver operating characteristic (ROC) curve.

Results

Forty-three FIAs were found in 43 patients. Eighteen (41.9%) patients who presented with aneurysmal symptoms were classified in the symptomatic group. In univariate analysis, male sex (P = 0.133), age (P = 0.013), FIAs type (P = 0.167), mural thrombus (P = 0.130), L_max (P = 0.066), CR_{stalk−cross} (P = 0.027), and CR_stalk−long (P = 0.055) tended to be associated with aneurysmal symptoms. In the cross-section model of multivariate analysis, male (P = 0.038), age (P = 0.018), and CR_{stalk−cross} (P = 0.048) were independently associated with aneurysmal symptoms. In the long-axis section model of multivariate analysis, male (P = 0.040), age (P = 0.010), CR_stalk−long (P = 0.046), and L_max (P = 0.019) were independently associated with aneurysmal symptoms. In the combination model of multivariate analysis, male (P = 0.027), age (P = 0.011), CR_{stalk−cross} (P = 0.030), and L_max (P = 0.020) were independently associated with aneurysmal symptoms. CR_{stalk−cross} has the highest accuracy in predicting aneurysmal symptoms (AUC = 0.701). The combination of CR_{stalk−cross} and L_max exhibited the highest performance in discriminating symptomatic from asymptomatic FIAs (AUC = 0.780).

Conclusion

Aneurysmal wall enhancement is associated with symptomatic FIAs. CR_{stalk−cross} and L_max were independent risk factors for aneurysmal symptoms. The combination of these two factors may improve the predictive performance of aneurysmal symptoms and may also help to stratify the instability of FIAs in future studies.

Quantification of aneurysm wall enhancement in intracranial fusiform aneurysms and related predictors based on high-resolution magnetic resonance imaging: a validation study

Background:

Aneurysm wall enhancement (AWE) in high-resolution magnetic resonance imaging (HR-MRI) has emerged as a new imaging biomarker of intracranial aneurysm instability.

Objective:

To determine a standard method of AWE quantification for predicting fusiform intracranial aneurysms (FIAs) stability by comparing the sensitivity of each parameter in identifying symptomatic FIAs. The predictors of AWE and FIA types were also identified.

Methods:

We retrospectively analyzed consecutive fusiform aneurysm patients who underwent HR-MRI from two centers. The aneurysm-to-pituitary stalk contrast ratio (CR_stalk), aneurysm enhancement ratio, and aneurysm enhancement index were extracted, and their sensitivities in discriminating aneurysm symptoms were compared using the receiver-operating characteristic curve. Morphological parameters of fusiform aneurysm were extracted based on 3D vessel model. Uni- and multivariate analyses of related predictors for AWE, CR_stalk, and FIA types were performed, respectively.

Results:

Overall, 117 patients (mean age, 53.3 ± 11.7 years; male, 75.2%) with 117 FIAs underwent HR-MRI were included. CR_stalk with the maximum signal intensity (CR_stalk-max) had the highest sensitivity in identifying symptomatic FIAs with an area under the curve value (0.697) and a cut-off value of 0.90. The independent predictors of AWE were aneurysm symptoms [(odds ratio) OR = 3.754, p = 0.003], aspirin use (OR = 0.248, p = 0.037), and the maximum diameter of the cross-section (OR = 1.171, p = 0.043). The independent predictors of CR_stalk-max were aneurysm symptoms (OR = 1.289, p = 0.003) and posterior circulation aneurysm (OR = 1.314, p = 0.001). Transitional-type showed higher rates of hypertension and mural thrombus over both dolichoectatic- and fusiform-type FIAs.

Conclusion:

CR_stalk-max may be the most reliable parameter to quantify AWE to distinguish symptomatic FIAs. It also has the potential to identify unstable FIAs. Several factors contribute to the complex pathophysiology of FIAs and need further validation in a larger cohort.

[Diagnosis and treatment of non-saccular vertebrobasilar aneurysms]

OBJECTIVE

To systematize the data on diagnosis and treatment of non-saccular vertebrobasilar aneurysms.

MATERIAL AND METHODS

We have analyzed modern and fundamental studies in the PubMed database for the period 1969-2020. The following keywords were used: non-saccular aneurysm, dolichoectasia, vertebrobasilar pool. Fifty-nine studies including 1 meta-analysis, 9 case reports, 24 reviews and 25 original articles were selected.

RESULTS

Analysis of literature data indicates various unresolved problems associated with difficult diagnosis and choice of treatment that results high rates of disability and mortality.

CONCLUSION

Data on anatomical features of non-saccular aneurysms, such as presence or absence of perforating arteries within the affected arterial segment, analysis of electrophysiological changes following brainstem compression by aneurysm can serve as factors that will improve treatment outcomes in these patients.

Intracranial Fusiform and Circumferential Aneurysms of the Main Trunk: Therapeutic Dilemmas and Prospects

Intracranial fusiform and circumferential aneurysms (IFCAs), especially those located on the main trunk, are uncommon and difficult to manage. Currently, literature focused on IFCAs on the main trunk of cerebral arteries is lacking. The treatment of IFCAs is still under debate. Therefore, in this review, we further explore the treatment of this complicated entity. In addition, we also present some interesting cases. Based on the literature review and our experience, we found that IFCAs are often located in the vertebrobasilar system and that ruptured or large symptomatic IFCAs are associated with increased mortality and higher rebleeding rates. The treatment strategies for IFCAs can be classified as deconstructive and reconstructive methods via open surgery and/or endovascular treatment (EVT). Currently, EVT is a popular method and the main therapeutic choice. In particular, flow diversion has revolutionized the treatment of IFCAs. Parent artery occlusion (PAO) with or without revascularization may still be considered a suitable choice. Complex IFCAs that cannot be resolved by EVT can also be treated via open surgery with or without extracranial–intracranial bypass. Targeted embolization for the weak points of IFCAs is a temporary or palliative choice that is rarely used. In summary, despite complications, both surgical treatment and EVT are effective options for appropriately selected cases. Due to the development of endovascular implants, EVT will have better prospects in the future.

Insights into the pathogenesis of cerebral fusiform aneurysms: high-resolution MRI and computational analysis

BACKGROUND

Intracranial fusiform aneurysms are complex and poorly characterized vascular lesions. High-resolution magnetic resonance imaging (HR-MRI) and computational morphological analysis may be used to characterize cerebral fusiform aneurysms.

OBJECTIVE

To use advanced imaging and computational analysis to understand the unique pathophysiology, and determine possible underlying mechanisms of instability of cerebral fusiform aneurysms.

METHODS

Patients with unruptured intracranial aneurysms prospectively underwent imaging with 3T HR-MRI at diagnosis. Aneurysmal wall enhancement was objectively quantified using signal intensity after normalization of the contrast ratio (CR) with the pituitary stalk. Enhancement between saccular and fusiform aneurysms was compared, as well as enhancement characteristics of fusiform aneurysms. The presence of microhemorrhages in fusiform aneurysms was determined with quantitative susceptibility mapping (QSM). Three distinct types of fusiform aneurysms were analyzed with computational fluid dynamics (CFD) and finite element analysis (FEA).

RESULTS

A total of 130 patients with 160 aneurysms underwent HR-MRI. 136 aneurysms were saccular and 24 were fusiform. Fusiform aneurysms had a significantly higher CR and diameter than saccular aneurysms. Enhancing fusiform aneurysms exhibited more enhancement of reference vessels than non-enhancing fusiform aneurysms. Ten fusiform aneurysms underwent QSM analysis, and five aneurysms showed microhemorrhages. Microhemorrhage-positive aneurysms had a larger volume, diameter, and greater enhancement than aneurysms without microhemorrhage. Three types of fusiform aneurysms exhibited different CFD and FEA patterns.

CONCLUSION

Fusiform aneurysms exhibited more contrast enhancement than saccular aneurysms. Enhancing fusiform aneurysms had larger volume and diameter, more enhancement of reference vessels, and more often exhibited microhemorrhage than non-enhancing aneurysms. CFD and FEA suggest that various pathophysiological processes determine the formation and growth of fusiform aneurysms.

Giant Vertebrobasilar Fusiform Aneurysm Mass Effect Heralds Rapid in Situ Thrombosis and Ischemic Stroke in the Setting of Ulcerative Colitis

Here we describe a case of brainstem infarction secondary to rapid thrombus formation in a giant vertebrobasilar fusiform aneurysm (GVBFA) that was preceded clinically by several months of headaches and dizziness initially attributable to mass effect. Less than a month after initial identification of the aneurysm, a large partially-occluding thrombus formed leading to infarction of the brainstem. Interestingly, this patient also had ulcerative colitis, which has been associated with acquired hypercoagulability. Balancing risk versus benefit in the management of GVBFA to prevent morbidity and mortality is very challenging; thus more information is needed to better stratify treatment options for patients, particularly those that may have an accelerating clinical course or co-morbidities that increase clotting risk.