Quantifying right atrial filling and emptying: A 4D‐flow MRI study

Purpose To quantitatively characterize the central role of vortex formation on the flow patterns and energy transfer within the right atrium (RA). Materials and Methods 4D‐flow magnetic resonance imaging (MRI) data with multiple encoding velocities was acquired in 12 healthy subjects at 3T. Particles entering the RA were classified according to the origin of entry. Vortex membership was numerically derived by assessing the location of pathline center of curvature relative to the vortex core, defined by Q‐criteria. Flow dynamics and energetics were assessed using paired t‐tests. Results The majority of flow (74%) passes through the RA in a single beat, with a very small volume fraction retained longer than two beats (