Simulation of Doppler ultrasound blood flow signals from stented sidewall aneurysm

Endovascular stent has an increasingly important application in the treatment of aneurysms. This study is to simulate Doppler ultrasound blood flow signals from a stented sidewall aneurysm based on a computational fluid dynamics model. For comparisons, a stented and non-stented sidewall aneurysm models are constructed respectively. Firstly the blood flow velocity distribution in the area of the sidewall aneurysm is calculated using the finite element method. Then the corresponding Doppler ultrasound blood flow signals are simulated using the cosine summation method. Finally the simulated signal spectrum is analyzed to estimate the mean frequency variation. Results show that the stented sidewall aneurysm model has substantially different mean frequency of simulated signals in the area of sidewall aneurysm from the non-stented model. Flow activities within the stented sidewall aneurismal area are markedly diminished and become stable. The mean frequency of simulated Doppler ultrasound blood flow signals from the stented sidewall aneurysm changes smoothly. These phenomena show that the endovascular stent can ease the vortex of the sidewall aneurysm effectively and attenuate the aneurysm rupture risk. At the same time, this study shows that the stent mesh spacing is an important factor for the effective treatment.