Currently, there is no method to predict outcome of endovascular treatment (EVAR) of type III B aortic dissections (TB-AD). A new image processing algorithm is presented for quantifying IS displacement from cine 2D phase contrast magnetic resonance images (2D pcMRI) towards a new classification of TB-AD based on IS mobility, Bulk motion of the true aortic lumen (tAB) center (ALC), maximum, minimum and average displacement of the boundary points composing the IS and tAB excluding the IS were quantified at two locations in one patient. Correlations of the ALC motion and the averaged temporal displacement AD(t) of IS and tAB excluding IS with the aortic flow waveform were calculated. Range of ALC motion was similar in both locations ( average 0.56 mm, max 1.37 mm) and correlated with the aortic flow waveform in the abdominal aorta but not the thoracic aorta. Range of displacement of the IS was from 1.27 mm to -1.64 mm (average 0.09 ± 0.07 mm) in the thoracic aorta, and from 0.38 mm to -3.38 mm (average 0.42 ± 0.23 mm) in the abdominal aorta. tAB motion excluding the IS was 1.21 mm to 0.84 mm (thoracic, average 0.13 ± 0.07 mm) and 0.52mm to -1.88 mm (abdominal, average 0.37 ± 0.11 mm). AD(t) for IS and tAB excluding the IS both correlated with aortic flow in the abdominal aorta only.