Admission supine chest radiographs are the initial and most commonly performed imaging study to evaluate the thorax following trauma. Whenever the chest radiograph is ambiguous or suggestive of a diagnosis of acute diaphragmatic injury, CT is the next study of choice since it is generally available and often used to examine other body regions of the polytraumatized patient. CT is usually diagnostic, particularly if supplemented by multiplanar reformations obtained using a thin slice thickness. Currently MR imaging is used at our trauma center to evaluate the diaphragm in patients with an indeterminate diagnosis after spiral CT. A limited MR imaging examination with T1-weighted sagittal and coronal imaging has been extremely accurate in establishing or excluding diaphragm injury.
Key words Diaphragm injury ± Computed tomography ± CT ± MR imagingThe initial diagnosis of diaphragm injury is often missed because distinct clinical and radiologic signs may be absent or subtle. Commonly, diaphragmatic injuries are associated with other major injuries to the solid organs, pelvis, central nervous system, and thoracic aorta that may divert attention from possible diaphragm injury [1, 2, 3]. Hence, diaphragm injury has always been a diagnostic challenge to both radiologist and trauma or emergency physician. A careful review of the literature indicates that most diaphragm injuries are caused by penetrating trauma (the ratio of penetrating to blunt trauma is 2:1) [3,4,5,6]. Diaphragm injury occurs in 6 % of patients following major blunt force trauma to the lower chest or abdomen and in 3±8 % of patients undergoing emergency celiotomy following blunt abdominal trauma [7,8,9,10,11,12,13,14,15,16]. Chest radiography serves today as the initial screening study performed to evaluate for diaphragm injury. Previous studies utilizing conventional CT have reported a poor accuracy in diagnosing diaphragm injury [17,18]. However, more recent literature indicates that the ability to obtain high-quality axial images with coronal and sagittal reformations using spiral CT has improved accuracy in diagnosing diaphragm injury [19]. This article reviews recent imaging advances in spiral CT that are helpful in diagnosing diaphragm injury.
AnatomyThe diaphragm is a thin, flat, half-dome-shaped muscle located between the pleuropericardial space above and the peritoneal space below. The most posterior portion of the diaphragm, the lumbar part, attaches to the medial and lateral arcuate ligaments and the periosteal surface of the upper three lumbar vertebrae on the right side and upper two vertebrae on the left side. Laterally the costal part attaches anteroposteriorly to the inner aspect of the sixth to twelfth ribs. The anterior diaphragm attaches anteriorly to the posterior aspect of the lower sternum and xiphoid process. Fibers from these three parts of the diaphragm converge to a central tendon. Three large openings interrupt the continuity of the diaphragm: the aortic hiatus, the lowest and most posterior, at the level of the thoracolumbar j...