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The spiral flow phantom: A new tool for vector flow estimator performance analysis

As new flow imaging methods are actively being developed, there is a growing need to devise appropriate phantoms that can holistically assess the accuracy of the derived flow estimates. Straight-tube models simply cannot serve this purpose, nor can spinning discs that simulate tissue motion instead of flow dynamics. Anthropomorphic bifurcation models are also not ideal, because their geometry does not embody all possible curvature angles and thus angle-specific estimation errors are prone to be overlooked. Here, we present a novel spiral phantom design with two unique features: 1) comprehensive multi-directional flow (i.e. from 0 to 360 deg); 2) space-time variability in flow speed. Both features are essential to foster meticulous evaluation of a flow estimator's performance.