Right main bronchus compression between the aorta and RPA

This infant presented with stridor and clinically a vascular ring was suspected.

The gated-CT revealed an interesting situation. There was a left-sided arch with a right descending aorta. Where the aorta was in the midline in its course from left to right, it caused a compression of the right main bronchus between itself and the right pulmonary artery (RPA). This is well seen on the successive axial images (Figs. 1-3), but good reconstruction images (Fig. 4) and color-coded 3D (Figs. 5, 6) help in understanding the abnormality.

There was no other pathology.