The Common Carotid Artery plays a vital role in supplying the brain, and its bifurcation
is susceptible to vascular diseases. It is often analyzed using computational fluid
dynamics (CFD) simulations, but it is challenging to prescribe boundary conditions
that approach patient-specific flow conditions. We examined six boundary condition
(BC) groups to determine the most accurate flow conditions aligning with available
measured data. We conducted CFD simulations on a stenotic carotid bifurcation, using
patient-specific Doppler ultrasound sonography velocity measurements at the inlet
and both outlets. Three BC methods used defined inlet flow rate and either constant
pressure (Basic), Windkessel model, or constant flow ratio (Murray) at the outlets.
Three other methods were defined with flow rates at two boundaries and constant pressure
at the third one. Defining two boundary flow rates shows the closest results to physiologically
valid data. However, the difficult Doppler measurements on the outlet branches can
inaccurately amplify velocity amplitudes and may detect a false flow direction. Therefore,
cross-sectional corrections were implemented to fit the outlet and inlet flow rates,
while keeping the measured velocity histories.Our results show that the Murray and
Basic methods, while easily available, exclude carotid-specific flow conditions by
disregarding downstream flow resistances. We conclude that a Windkessel-method can
produce the most accurate results without forcing outflow conditions. However, usually
unavailable measurements are necessary for its application. Simulations with outlet-defined
volume flow can also produce physiologically valid solutions but require the application
of cross-sectional geometry correction.
