The posterior tracheal band: correlation between computed tomography and chest radiography.

As seen on the lateral chest radiograph, the posterior tracheal band (PTB) is useful in evaluating the retrotracheal area. The anatomical basis of its variations on the lateral chest radiograph were analyzed by comparison with computed tomography (CT). Lack of visualization or occasional thickening of the PTB is explained on an anatomical basis. Such variations are distinguishable from retrotracheal abnormalities on CT.