False lumen regurgitation fraction and energy loss in the aorta measured using four-dimensional flow MRI to predict expansion of acute uncomplicated type B aortic dissection: a prospective study.

Aim: To assess the relationship between four-dimensional (4D)-flow-derived false lumen regurgitation fraction (FLRF) and energy loss (EL) percentage in the descending thoracic aorta (DTA) with the aortic growth rate in uncomplicated type B aortic dissection (uTBAD).

Methods And Materials: In this prospective study performed on 15 patients with uTBAD, computed tomography (CT) angiography and 4D-flow magnetic resonance imaging (MRI) were performed at the initial presentation with follow-up CT at 2 years. 4D-flow parameters, including maximum peak systolic velocity (PSV), FLRF, and percentage of EL were measured using Circle CV42.