This is a potentially life-threatening medical emergency. The patient should have immediate upright frontal and lateral soft tissue views of the neck to evaluate the airway. Croup and epiglottitis have different patterns of pathology and can usually be distinguished radiographically. The patient should be accompanied at all times by medical personnel capable of intubating the child if necessary. Imaging should never be performed in the supine position since this will potentially compromise the airway. CT of the neck with IV contrast may be useful if abscess, foreign body or mass is suspected. A barium swallow is indicated if a vascular ring is suspected, with MRI confirmation if the barium swallow is positive. US & NM aren't usually indicated.