Evaluation of flow volume and flow patterns in the patent false lumen of chronic aortic dissections using velocity-encoded cine magnetic resonance imaging

In 21 patients with chronic aortic dissections and proven patent false lume ns, the how volume and flow patterns in the patent false lumens was evaluat ed using velocity-encoded cine magnetic resonance imaging (VENC-MRI) and th e relationship between the flow characteristics and aortic enlargement was retrospectively examined. Flow patterns in the false lumen were divided int o 3 groups: pattern A with primarily antegrade how (n=6), pattern R with pr imarily retrograde flow (n=3), and pattern B with bidirectional flow (n=12) . In group A, the rate of flow volume in the false lumen compared to the to tal flow volume in true and false lumens (%TFV) and the average rate of enl argement of the maximum diameter of the dissected aorta per year (Delta D) were significantly greater than in groups R and B (%TFV: 74.1+/-0.07 vs 15. 2+/-0.03 vs 11.8+/-0.04, p<0.01; Delta D: 3.62+/-0.82 vs 0 vs 0.58+/-0.15 m m/year, p<0.05, respectively). There was a significant correlation between %TFV and Delta D (r=0.79, p<0.0001). Evaluation of flow volume and flow pat terns in the patent false lumen using VENC-MRI may be useful for predicting enlargement of the dissected aorta.