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New method for retrospective study of hemodynamic changes before and after aneurysm formation in patients with ruptured or unruptured aneurysms.

Le WJ, Zhu YQ, Li MH, Yan L, Tan HQ, Xiao SM, Cheng YS - BMC Neurol (2013)

Bottom Line: Prospective observation of hemodynamic changes before and after formation of brain aneurysms is often difficult.Arterial geometries obtained from three-dimensional digital subtraction angiography of cerebral angiograms were used for flow simulation by employing finite-volume modeling.However, more complicated flow patterns (often with an inflow jet or narrowed impaction zone) were more likely to be observed in ruptured aneurysm.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiology, The Sixth Affiliated People's Hospital, Medical School of Shanghai Jiao Tong University, No, 600, Yi Shan Road, Shanghai 200233, China. zhuyueqi@hotmail.com.

ABSTRACT

Background: Prospective observation of hemodynamic changes before and after formation of brain aneurysms is often difficult. We used a vessel surface repair method to carry out a retrospective hemodynamic study before and after aneurysm formation in a ruptured aneurysm of the posterior communicating artery (RPcomAA) and an unruptured aneurysm of the posterior communicating artery (URPcomAA).

Methods: Arterial geometries obtained from three-dimensional digital subtraction angiography of cerebral angiograms were used for flow simulation by employing finite-volume modeling. Hemodynamic parameters such as wall shear stress (WSS), blood-flow velocity, streamlines, pressure, and wall shear stress gradient (WSSG) in the aneurysm sac and at the site of aneurysm formation were analyzed in each model.

Results: At "aneurysm" status, hemodynamic analyses at the neck, body, and dome of the aneurysm revealed the distal aneurysm neck to be subjected to the highest WSS and blood-flow velocity, whereas the aneurysm dome presented the lowest WSS and blood-flow velocity in both model types. More apparent changes in WSSG at the aneurysm dome with an inflow jet and narrowed impaction zone were revealed only in the RPcomAA. At "pre-aneurysm" status, hemodynamic analyses in both models showed that the region of aneurysm formation was subjected to extremely elevated WSS, WSSG, and blood-flow velocity.

Conclusions: These data suggest that hemodynamic analyses in patients with ruptured or unruptured aneurysms using the vessel surface repair method are feasible, economical, and simple. Our preliminary results indicated that the arterial wall was subjected to elevated WSS, WSSG and blood-flow velocity before aneurysm generation. However, more complicated flow patterns (often with an inflow jet or narrowed impaction zone) were more likely to be observed in ruptured aneurysm.

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Hemodynamic analyses of the RPcomAA at the aneurysm status. A, Two-dimensional-DSA and 3D-DSA reconstruction images of the RPcomAA. B, Hemodynamic analyses in terms of WSS, pressure, velocity field, streamlines, and WSSG show elevated WSS and low pressure at the distal aneurysm neck, and decreased WSS and elevated pressure at the aneurysm dome. A complex blood flow pattern is observed in the aneurysm sac with a narrowed inflow jet and impaction zone. C, Quantification along the longitudinal section of the aneurysm wall shows significant changes in the distribution of WSS and WSSG at the peak of the systolic period. WSS, wall shear stress; P, pressure VMP, von Mises pressure; VF, velocity field; SL, streamlines; WSSG, wall shear stress gradient.
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Figure 2: Hemodynamic analyses of the RPcomAA at the aneurysm status. A, Two-dimensional-DSA and 3D-DSA reconstruction images of the RPcomAA. B, Hemodynamic analyses in terms of WSS, pressure, velocity field, streamlines, and WSSG show elevated WSS and low pressure at the distal aneurysm neck, and decreased WSS and elevated pressure at the aneurysm dome. A complex blood flow pattern is observed in the aneurysm sac with a narrowed inflow jet and impaction zone. C, Quantification along the longitudinal section of the aneurysm wall shows significant changes in the distribution of WSS and WSSG at the peak of the systolic period. WSS, wall shear stress; P, pressure VMP, von Mises pressure; VF, velocity field; SL, streamlines; WSSG, wall shear stress gradient.

Mentions: In both patients, a similar decrease of WSS and increase in pressure were observed from the aneurysm neck to the dome in the RPcomAA (WSS, 15.40 ± 10.31 Pa at the neck vs. 3.847 ± 2.843 Pa at the dome; pressure, 653.4 ± 207.9 Pa at the neck vs. 839.4 ± 178.6 Pa at the dome) and in the UPcomAA (WSS. 11.38 ± 2.417 Pa at the neck vs. 4.85 ± 0.2772 Pa at the dome; pressure: 462.8 ± 213.6 Pa at the neck vs. 905 ± 73.18 Pa at the dome). The velocity field and streamlines indicated complex turbulent blood flow in the RPcomAA compared with the normal ordered vortex flow observed in the URPcomAA. High velocity of blood flow often appeared at the distal end of the neck and decreased from the neck to the dome in the RPcomAA (1075 ± 632.6 vs. 522.2 ± 328.6 m/s) and URPcomAA (1176 ± 364.4 vs. 511.6 ± 27.7 m/s). A more significant change in WSSG was observed in the RPcomAA than in the URPcomAA (Figures 2, 3 and 4A).


New method for retrospective study of hemodynamic changes before and after aneurysm formation in patients with ruptured or unruptured aneurysms.

Le WJ, Zhu YQ, Li MH, Yan L, Tan HQ, Xiao SM, Cheng YS - BMC Neurol (2013)

Hemodynamic analyses of the RPcomAA at the aneurysm status. A, Two-dimensional-DSA and 3D-DSA reconstruction images of the RPcomAA. B, Hemodynamic analyses in terms of WSS, pressure, velocity field, streamlines, and WSSG show elevated WSS and low pressure at the distal aneurysm neck, and decreased WSS and elevated pressure at the aneurysm dome. A complex blood flow pattern is observed in the aneurysm sac with a narrowed inflow jet and impaction zone. C, Quantification along the longitudinal section of the aneurysm wall shows significant changes in the distribution of WSS and WSSG at the peak of the systolic period. WSS, wall shear stress; P, pressure VMP, von Mises pressure; VF, velocity field; SL, streamlines; WSSG, wall shear stress gradient.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4228259&req=5

Figure 2: Hemodynamic analyses of the RPcomAA at the aneurysm status. A, Two-dimensional-DSA and 3D-DSA reconstruction images of the RPcomAA. B, Hemodynamic analyses in terms of WSS, pressure, velocity field, streamlines, and WSSG show elevated WSS and low pressure at the distal aneurysm neck, and decreased WSS and elevated pressure at the aneurysm dome. A complex blood flow pattern is observed in the aneurysm sac with a narrowed inflow jet and impaction zone. C, Quantification along the longitudinal section of the aneurysm wall shows significant changes in the distribution of WSS and WSSG at the peak of the systolic period. WSS, wall shear stress; P, pressure VMP, von Mises pressure; VF, velocity field; SL, streamlines; WSSG, wall shear stress gradient.
Mentions: In both patients, a similar decrease of WSS and increase in pressure were observed from the aneurysm neck to the dome in the RPcomAA (WSS, 15.40 ± 10.31 Pa at the neck vs. 3.847 ± 2.843 Pa at the dome; pressure, 653.4 ± 207.9 Pa at the neck vs. 839.4 ± 178.6 Pa at the dome) and in the UPcomAA (WSS. 11.38 ± 2.417 Pa at the neck vs. 4.85 ± 0.2772 Pa at the dome; pressure: 462.8 ± 213.6 Pa at the neck vs. 905 ± 73.18 Pa at the dome). The velocity field and streamlines indicated complex turbulent blood flow in the RPcomAA compared with the normal ordered vortex flow observed in the URPcomAA. High velocity of blood flow often appeared at the distal end of the neck and decreased from the neck to the dome in the RPcomAA (1075 ± 632.6 vs. 522.2 ± 328.6 m/s) and URPcomAA (1176 ± 364.4 vs. 511.6 ± 27.7 m/s). A more significant change in WSSG was observed in the RPcomAA than in the URPcomAA (Figures 2, 3 and 4A).

Bottom Line: Prospective observation of hemodynamic changes before and after formation of brain aneurysms is often difficult.Arterial geometries obtained from three-dimensional digital subtraction angiography of cerebral angiograms were used for flow simulation by employing finite-volume modeling.However, more complicated flow patterns (often with an inflow jet or narrowed impaction zone) were more likely to be observed in ruptured aneurysm.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiology, The Sixth Affiliated People's Hospital, Medical School of Shanghai Jiao Tong University, No, 600, Yi Shan Road, Shanghai 200233, China. zhuyueqi@hotmail.com.

ABSTRACT

Background: Prospective observation of hemodynamic changes before and after formation of brain aneurysms is often difficult. We used a vessel surface repair method to carry out a retrospective hemodynamic study before and after aneurysm formation in a ruptured aneurysm of the posterior communicating artery (RPcomAA) and an unruptured aneurysm of the posterior communicating artery (URPcomAA).

Methods: Arterial geometries obtained from three-dimensional digital subtraction angiography of cerebral angiograms were used for flow simulation by employing finite-volume modeling. Hemodynamic parameters such as wall shear stress (WSS), blood-flow velocity, streamlines, pressure, and wall shear stress gradient (WSSG) in the aneurysm sac and at the site of aneurysm formation were analyzed in each model.

Results: At "aneurysm" status, hemodynamic analyses at the neck, body, and dome of the aneurysm revealed the distal aneurysm neck to be subjected to the highest WSS and blood-flow velocity, whereas the aneurysm dome presented the lowest WSS and blood-flow velocity in both model types. More apparent changes in WSSG at the aneurysm dome with an inflow jet and narrowed impaction zone were revealed only in the RPcomAA. At "pre-aneurysm" status, hemodynamic analyses in both models showed that the region of aneurysm formation was subjected to extremely elevated WSS, WSSG, and blood-flow velocity.

Conclusions: These data suggest that hemodynamic analyses in patients with ruptured or unruptured aneurysms using the vessel surface repair method are feasible, economical, and simple. Our preliminary results indicated that the arterial wall was subjected to elevated WSS, WSSG and blood-flow velocity before aneurysm generation. However, more complicated flow patterns (often with an inflow jet or narrowed impaction zone) were more likely to be observed in ruptured aneurysm.

Show MeSH
Related in: MedlinePlus