Elsevier

Academic Radiology

Volume 16, Issue 10, October 2009, Pages 1201-1207
Academic Radiology

Original investigation
Hemodynamics and Rupture of Terminal Cerebral Aneurysms

https://doi.org/10.1016/j.acra.2009.03.022Get rights and content

Rationale and Objectives

The objective of this study was to investigate the relationship between hemodynamics patterns and aneurysmal rupture in cerebral aneurysms of the same morphology regardless their location. Particularly, terminal aneurysms in both the anterior and posterior circulation were studied.

Materials and Methods

A total of 42 patient-specific vascular models were constructed from three-dimensional rotational angiography images. All patients had terminal aneurysms at different arteries: a) middle cerebral; b) anterior communicating; c) internal carotid (terminus); d) internal carotid–posterior communicating; e) basilar; or f) anterior cerebral. Hemodynamics information (intra-aneurysmal velocity and wall shear stress distributions) was derived from image-based computational fluid dynamics models with realistic patient-specific anatomies.

Results

The group of aneurysms with an inflow jet that splits in two secondary jets, one of which enters the aneurysm before reaching one of the daughter vessels (type B), had the highest peak wall shear stress (WSS) and the highest rupture rate. The peak WSS averaged over each flow type showed a higher value in the ruptured group. The average peak WSS in the ruptured group (all types) was 188 dyn/cm2 (compared to 118 dyn/cm2 for the unruptured).

Conclusions

This finding is in agreement with a previous work in which only anterior communicating artery aneurysms were investigated. The significance of these findings is that, if they are statistically confirmed with larger number of cases, flow types could be directly observed during angiographic examinations and linked to WSS categories that may help evaluate which aneurysms are more likely to rupture.

Section snippets

Patients and Images

A total of 42 consecutive terminal cerebral aneurysms were selected from our database for this study. Patients referred to the interventional neuroradiological service of the Inova Fairfax Hospital (Virginia) between 2003 and 2005, and diagnosed with cerebral aneurysms by conventional catheter angiograms and three-dimensional rotational angiography were considered. Rotational angiography images were obtained during a 180° rotation and imaging at 15 frames per second for a total of 8 seconds, by

Results

It was found that in average ruptured aneurysms had larger MWSS than unruptured aneurysms. In particular, the MWSS averaged over the ruptured aneurysm group (271 dyn/cm2) exceeded by a factor larger than two that of the unruptured group (118 dyn/cm2). A t-test showed that the difference is significant at 95% of confidence level (P = .04). It was also observed that 90% of the aneurysms with MWSS higher than 250 dyn/cm2 were ruptured. Two aneurysms, one in the middle cerebral artery and one in

Conclusion

Cerebral aneurysms are pathological dilations of the arterial wall frequently located near arterial bifurcations in the circle of Willis 25, 26, 27. The most serious consequence is their rupture and intracranial hemorrhage, with an associated high mortality and morbidity rate 28, 29, 30, 31. Intracranial aneurysms are particularly difficult to treat, and often do not produce symptoms before they rupture (32). Improvements of neuroradiological techniques have resulted in more frequent detection

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