eventration

Eventration is a condition where all or a portion of hemidiaphragm is permanently elevated yet retains its continuity and normal attachments to the costal margins. It is a congenital anomaly due to the failure of muscular development of one portion or entire part of the diaphragm. Eventration occurs more often in males than in females. This most commonly presents in childhood on the right side, whereas in adults more often on the left side. Partial eventrations usually manifest themselves as smooth, convex mounds interrupting the gentle curverture of the diaphragm normally seen on chest radiographs or MRI (Fig 1). Complete eventration shows the smooth elevation of the hemidiaphragm on radiographs, with slight paradoxical or little movement during inspiration on fluoroscopy and may be difficult or impossible to distinguish from diaphragmatic paralysis (Fig 2). CT, MR imaging, ultrasonography can be used to determine the contents of the eventration.

Fig 1: PARTIAL EVENTRATION

A. Posteroanterior and B. lateral radiographs in a 54-year-old woman demonstrate a broad, smooth bulging of anterolateral segment of the left diaphragm.

C. Coronal and D. sagittal T1-weighted MRI in a 65-year-old man shows a upward bulging of the posterior segment of the left diaphragm.

Fig 2: COMPLETE EVENTRATION.

Coronal T1-weighted MRI in a 57-year-old man shows an upward bulging of the entire right diaphragm.

Dynamic MR imaging shows a slight paradoxal movement during a sniff.