Tag: aneurysm morphology

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Impact of Clinical Variables and Aneurysm Morphology on Hemorrhage Volume and Clinical Outcomes

Neurosurgery 98:394–403, 2026

This study investigates determinants of aneurysmal subarachnoid hemorrhage (aSAH) volume and its effect on early clinical outcomes using objective, semiautomated CT quantification in 200 ruptured intracranial aneurysms. Multivariate analysis identified older age, higher Hunt and Hess score, and bifurcation aneurysm location as independent predictors of larger aSAH volume, while sex (female) correlated with lower volumes.

Outcome analysis stratified by age showed that in patients 18–64 years greater aSAH volume increased risk of delayed cerebral ischemia, clinical vasospasm, and 7-day mortality; in patients ≥65 years larger volume was associated only with 7-day mortality. The authors recommend multicenter studies using objective quantification to validate age-specific clinical implications.

Hemorrhage Volume Predictors: Larger aneurysmal subarachnoid hemorrhage (aSAH) volumes are associated with older age, higher Hunt and Hess (HH) scores at admission, and ruptured aneurysms located at arterial bifurcations, especially the basilar tip; women have lower hemorrhage volumes than men.

Aneurysm Morphology: Aneurysm size, aspect ratio (AR), size ratio (SR), and irregular morphology do not significantly influence aSAH volume, although bifurcation location is a strong predictor of increased hemorrhage volume.

Hemodynamics Over Morphology: Hemorrhage volume appears to be more influenced by cerebral flow dynamics and aneurysm location (bifurcation vs. sidewall) than by traditional morphological parameters such as size or shape.

Age-Dependent Outcomes: In patients aged 18–64 years, larger aSAH volume is linked to increased risk of delayed cerebral ischemia (DCI), clinical vasospasm, and 7-day mortality; in patients ≥65 years, larger volume is only associated with increased 7-day mortality, not DCI or vasospasm.

Elderly Population Specifics: Lower risk of vasospasm and DCI in elderly patients may be due to arteriosclerotic changes and larger cisternal spaces, which allow greater blood accumulation without corresponding clinical symptoms.

Objective Measurement: Use of semiautomated, machine learning-based tools (e.g., MATLAB segmentation) provides more reliable and reproducible quantification of hemorrhage volume compared to subjective grading systems.

Clinical Implications: Objective hemorrhage quantification could improve risk stratification, facilitate personalized treatment, and enhance understanding of blood clearance and outcomes after aSAH.

Research Recommendations: Multicenter studies using objective quantification methods are needed for validation and to refine management strategies for ruptured aneurysms, considering age-specific differences

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The influence of aneurysm morphology on the volume of hemorrhage after rupture

J Neurosurg 136:1015–1023, 2022

Factors determining the risk of rupture of intracranial aneurysms have been extensively studied; however, little attention is paid to variables influencing the volume of bleeding after rupture. In this study the authors aimed to evaluate the impact of aneurysm morphological variables on the amount of hemorrhage.

METHODS This was a retrospective cohort analysis of a prospectively collected data set of 116 patients presenting at a single center with subarachnoid hemorrhage due to aneurysmal rupture. A volumetric assessment of the total hemorrhage volume was performed from the initial noncontrast CT. Aneurysms were segmented and reproduced from the initial CT angiography study, and morphology indexes were calculated with a computer-assisted approach. Clinical and demographic characteristics of the patients were included in the study. Factors influencing the volume of hemorrhage were explored with univariate correlations, multiple linear regression analysis, and graphical probabilistic modeling.

RESULTS The univariate analysis demonstrated that several of the morphological variables but only the patient’s age from the clinical-demographic variables correlated (p < 0.05) with the volume of bleeding. Nine morphological variables correlated positively (absolute height, perpendicular height, maximum width, sac surface area, sac volume, size ratio, bottleneck factor, neck-to-vessel ratio, and width-to-vessel ratio) and two correlated negatively (parent vessel average diameter and the aneurysm angle). After multivariate analysis, only the aneurysm size ratio (p < 0.001) and the patient’s age (p = 0.023) remained statistically significant. The graphical probabilistic model confirmed the size ratio and the patient’s age as the variables most related to the total hemorrhage volume.

CONCLUSIONS A greater aneurysm size ratio and an older patient age are likely to entail a greater volume of bleeding after subarachnoid hemorrhage.

 

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Relationship of A1 segment hypoplasia to anterior communicating artery aneurysm morphology and risk factors for aneurysm formation

J Neurosurg 127:89–95, 2017

Hypoplasia of the A1 segment of the anterior cerebral artery is frequently observed in patients with anterior communicating artery (ACoA) aneurysms. The effect of this anatomical variant on ACoA aneurysm morphology is not well understood.

METHODS Digital subtraction angiography images were reviewed for 204 patients presenting to the authors’ institution with either a ruptured or an unruptured ACoA aneurysm. The ratio of the width of the larger A1 segment to the smaller A1 segment was calculated. Patients with an A1 ratio greater than 2 were categorized as having A1 segment hypoplasia. The relationship of A1 segment hypoplasia to both patient and aneurysm characteristics was then assessed.

RESULTS Of 204 patients that presented with an ACoA aneurysm, 34 (16.7%) were found to have a hypoplastic A1. Patients with A1 segment hypoplasia were less likely to have a history of smoking (44.1% vs 62.9%, p = 0.0410). ACoA aneurysms occurring in the setting of a hypoplastic A1 were also found to have a larger maximum diameter (mean 7.7 vs 6.0 mm, p = 0.0084). When considered as a continuous variable, increasing A1 ratio was associated with decreasing aneurysm dome-to-neck ratio (p = 0.0289). There was no significant difference in the prevalence of A1 segment hypoplasia between ruptured and unruptured aneurysms (18.9% vs 10.7%; p = 0.1605).

CONCLUSIONS Our results suggest that a hypoplastic A1 may affect the morphology of ACoA aneurysms. In addition, the relative lack of traditional risk factors for aneurysm formation in patients with A1 segment hypoplasia argues for the importance of hemodynamic factors in the formation of ACoA aneurysms in this anatomical setting.

 

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