Ans. B. Helical CTCongenital lobar emphysemaa. Progressive over inflation of one or multiple lobes, usually of the upper lobes or right middle lobe.b. Left upper lobe is most commonly affected (43%).c. The word emphysema is misnomer as there is no alveolar wall destructiond. The etiology is unknown in many cases but is related to obstruction of the bronchus by a ball valve mechanisme. Present with respiratory distress (90%) with progressive cyanosis within 6 months of life.f. Associated congenital anomalies (cardiovascular) are seen in 50% casesg. Treatment is by lung resection