Interpretation of chest radiograph and imaging in neonatal respiratory disorders

Pulmonary disorders are one of the common causes of morbidity in neonates. Treating physicians and radiologists are often frustrated and perplexed due to the difficulty in interpretation of the chest radiograph in neonates. A complete knowledge of anatomy, embryology and pathophysiology of various conditions affecting the respiratory system is critical in avoiding such confusion and is important in the interpretation of chest radiograph.¹ We initially describe normal appearance and pitfalls of a chest radiograph and few common radiographic appearances and their causes.

Respiratory distress is the most common neonatal presenting problem. Although various conditions may lead to respiratory distress, we focus here on the respiratory causes. As the initial mode of investigation, a chest radiograph including an abdominal radiograph must be routinely performed in all these patients. The latter is useful in the diagnosis of a diaphragmatic hernia. A normal chest radiograph shows completely aerated bilateral lungs. The diaphragm is usually seen at about 8^th intercostals space and the trachea is slightly deviated to the right due to the presence of left sided aortic arch. The thymus usually causes widening of superior mediastinum. Bilateral lungs may appear hazy even in normal neonates if radiograph is performed early, due to the presence of lung fluid which clears within 24 hours. Skin fold artefacts are common in neonates and should not be mistaken for pneumothorax.