Vascular rings and their effect on tracheal geometry

The major clinical impact of vascular rings in children is tracheal compression, which presents with recurrent symptoms of stridor, noisy breathing, and wheezing. This study tests the hypothesis that symptomatic patients have altered tracheal geometry compared to nonsymptomatic individuals. We retrospectively reviewed the tracheal dimensions (area and longest and shortest diameters) as visualized by magnetic resonance imaging from the cupola of the lung to the carina of 49 patients referred for evaluation of a vascular ring. The smallest dimension relative to the largest dimension (% of maximum) and the coefficient of variation (CoVar; standard deviation/mean) were assessed for each parameter. In all parameters measured (area and longest and shortest diameters), patients with symptoms due to vascular rings had significantly different values than patients without symptoms. The % of maximum was significantly smaller (area, 48.6 vs 62.1 %; longest diameter, 41.0 vs 54.0%; shortest diameter, 45.0 vs 56.5%) and the CoVar was significantly greater (area, 0.26 vs 0.18; longest diameter, 0.31 vs 0.22; shortest diameter, 0.28 vs 0.19) in symptomatic individuals than in nonsymptomatic individuals. Patients with vascular rings who are symptomatic have significantly altered tracheal geometry compared to nonsymptomatic individuals. Magnetic resonance imaging is a useful tool for visualizing both the cardiovascular and the tracheal anatomy in patients with vascular rings and provides useful information for the management and care of these patients.