Multimodality imaging of the pediatric diaphragm: anatomy and pathologic conditions

Apart from serving as an important landmark for description and staging of pathologic conditions, the diaphragm is also affected by various types of pathologic conditions in children. Congenital abnormalities affecting the diaphragm include aplasia or hypoplasia, accessory diaphragm, eventration, and hernias. Congenital diaphragmatic hernias (CDHs) include Bochdalek, Morgagni, and hiatal hernias. Although survival rates are improving with the advent of new therapies, there is still significant morbidity and mortality associated with CDH. The morbidity and mortality depend on the associated congenital anomalies, the size of the hernia, and the degree of lung hypoplasia. Newer surgical repair techniques for the diaphragm have resulted in new postoperative complications and imaging appearances. Ultrasonography has become the modality of choice for evaluation of diaphragmatic paralysis. The diaphragm is uncommonly affected by trauma in children; when diaphragmatic injury is present, it usually indicates high-impact trauma associated with other severe injuries. Primary diaphragmatic tumors are very rare in children, with rhabdomyosarcoma being the most common. The diaphragm may also be secondarily involved by invasion of an adjacent tumor. Radiologists should have an understanding of the embryology, anatomy, and anatomic variations of the diaphragm and should be aware of the imaging appearances of pathologic conditions affecting the diaphragm in children.