Pulmonary artery sling: definitive diagnosis by colour Doppler flow mapping avoiding cardiac catheterisation.

Pulmonary artery sling is a rare abnormality that usually presents in infancy with wheeze or stridor. Diagnoses by cross sectional echocardiography, computed tomography, and magnetic resonance imaging have been described but pulmonary arteriography was regarded as essential for a definite diagnosis. The use of colour Doppler adds to the diagnostic certainty of cross sectional echocardiography and colour Doppler provided a definite diagnosis in an infant that allowed surgical repair without the need for cardiac catheterisation. Postoperative flow through the left pulmonary artery was also assessed by Doppler, and this avoided the need for repeat catheterisation or perfusion lung scanning.