Straightforward quantification of variations of flow patterns within aneurysms fails to accurately describe flow patterns of interest. We applied a multiscale decomposition of the flow in well-defined patterns to detect and quantify flow patterns in an aneurysm phantom that was studied with three different modalities: MRI, computational fluid dynamics, and particle image velocimetry. The method intuitively visualizes main patterns such as locally uniform flow, in- and outflow, and vortices. It is shown that this method is a valuable tool to quantitatively compare scale-dependent complex flow patterns in aneurysms.