What is your differential diagnosis (based on x-ray findings) ?
1- Bronchial atresia. 2- Foreign body, endobronchial lesion or mucus plug. 3- Focal extrinsic compression e.g. vascular anomaly.
If you find an x-ray abnormality that is most likely represent CLE, what is your next step?
Chest CT scan with IV contrast.
There is left upper lobe lucency, attenuated vascularity and overinflation with resultant mediastinal shift to the right.