Anatomic variations and abnormalities in the diaphragm seen with US.

The authors report their experience with diaphragmatic structures that simulate intrahepatic masses at abdominal ultrasonography (US). In a series of 74 patients, diaphragmatic slips were the most common finding (34 patients). The slips could be differentiated from masses by scanning along their long axis to demonstrate elongated structures with multiple linear echoes. Scalloping of the diaphragm, associated with multiple slips, was seen in 10 patients. Partial eventration was found in 23. Inversion of a hemidiaphragm, caused by a large pleural effusion or intrathoracic mass, was seen in 13 patients. Pleural masses affecting the diaphragm were seen in 13 patients; focal hypertrophy of a diaphragmatic crus simulated a mass in three. Real-time US allowed the differentiation of diaphragmatic abnormalities from lesions.