Parametric visualization of flow disturbances from cineangiographically acquired image sequences is demonstrated for non-steady background flow conditions using a finite element method (FEM) simulation of flows in an arterial model. This work continues earlier efforts to obtain visualizations of flow disturbances using cineangiographic image sequences. Parametric images descriptive of flow disturbances under steady background flow conditions were demonstrated as part of that previous study. Using numerical simulations, the objective of the present study is to assess the effects of non-steady background flows on flow disturbance visualization. The same geometry of the arterial model, same peak Reynolds number, and same visualization technique were used in both simulations. Although the parametric disturbance images changed somewhat, the visualizations continued to indicate the presence and extent of the flow disturbances, even for non-steady background flow conditions. The results sustain the potential diagnostic value of the approach for use in human vessel assessment. The two studies are compared and explained relative to the background flow conditions and the implications of the study for in vivo application are discussed.