Flow Determination Using Computed Tomography: Application to Aortic Dissection

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Abstract
The CT method of flow determination evaluated in this study was based on the application of contrast enhancement dynamics. In order to characterize flow, such parameters as mean transit time, rise time, peak CT value, curve width and variance, and others were derived from the venoarterial indicator dilution curves using a perfect mixers-in-series model of curve fitting analysis and a bolus injection of contrast medium. The technique was first validated in a steady state phantom model that simulated in vivo conditions of right-sided mixing closely by the introduction of a number of mixers. A series of flows through small tubes was measured. Good correlation was obtained (r=.85). For a fixed number of mixers, the central second moment of the primary peak of the indicator dilution curve or variance decreased with increasing flow and peak CT value increased. Applied to the clinical situation, this method would allow characterization of blood flow using an intravenous bolus of contrast.