Computational Simulation of Flow in a Dissecting Aortic Aneurysm Reconstructed From CT Images

We have simulated blood flow through the shape of dissecting aortic aneurysm reconstructed from CT images. An aortic dissection is a tear in the inner lining of the aorta, creating a space between the inner and outer layers called a false lumen. The pipe where the usual bloodstream flows is called a true lumen. The thrombus or the bloodstream exists at the exit of the false lumen. Currently, there are not flow simulations of dissecting aortic aneurysms that use the individual patient’s shape. Under these circumstances, we thought that it would be useful to examine the stress that joins the vessel walls by numerical simulation, in order to changes after the onset of the disease. To obtain accurate simulation results, we examined a method for obtaining a highly accurate dissected aortic aneurysm shape. We assumed the maximum Reynolds number for systolic pressure. The constant flow was given by the entrance boundary. The calculation scheme is a finite volume method. The Reynolds number was about 9000. The result showed that flow in the false lumen was rotational flow and lower than that in the true lumen. Flow in the true lumen was not rotational flow. In general, MRI imagery has shown that flow in the aortic arch is rotational. The magnitude of the velocity in the true lumen was about 11 times the velocity in the false lumen. Therefore, high wall shear stress was showed three areas at wall in true lumen. Both wall shear stress and pressure values were high in the re-entry portion.