Emergency Radiology (2004) 10: 334–336 DOI 10.1007/s10140-004-0335-6
CASE REPORT
Mert Koroglu Æ Randy D. Ernst Æ Aytekin Oto William J. Mileski
Traumatic diaphragmatic rupture: can oral contrast increase CT detectability?
Accepted: 14 January 2004 / Published online: 23 March 2004 Ó ASER 2004
Abstract Traumatic diaphragmatic rupture is a frequently missed diagnosis. We present a patient with traumatic diaphragmatic hernia. Diagnosis was suggested by a emergent computed tomography (CT) examination without oral contrast. Diaphragmatic rupture and herniation of stomach were confirmed by repeating CT examination after the administration of oral contrast and using multiplanar reconstruction. Keywords Trauma Æ Diaphragm Æ CT
Introduction Traumatic diaphragmatic injuries remain a diagnostic challenge for radiologists and surgeons [1, 2]. Early diagnosis and repair of diaphragmatic rupture are needed to decrease the amount of fibrosis and to avoid visceral compromise due to thoracic herniation [3, 4]. Detection of diaphragmatic rupture with imaging is becoming more important since numerous patients with additional injuries are being treated conservatively [1]. In this case report we want to emphasize the role of oral contrast and multiplanar reconstructions in computed tomography (CT) examinations for the detection of diaphragmatic rupture.
M. Koroglu (&) Æ R. D. Ernst Æ A. Oto Department of Radiology, University of Texas Medical Branch at Galveston, Galveston, Texas, USA E-mail:
[email protected] Tel.: +90-246227-9469 W. J. Mileski Department of General Surgery, University of Texas Medical Branch at Galveston, Galveston, Texas, USA M. Koroglu Hizirbey M. 1544 S. No 72/3, 32040 Isparta, Turkey
Case report After a motor vehicle accident, a 37-year-old man was admitted to hospital with complaints of dyspnea and chest pain. He was hemodynamically stable with blood pressure of 161/101 mmHg, pulse 90 bpm, respiratory rate 20/min and oxygen saturation 97%. He had tenderness on palpation of the left subcostal region and left upper quadrant with no wounds, swelling, or hematomas. An initial chest X-ray obtained in the supine position demonstrated elevation of the left hemidiaphragm and increased opacity of the left lung base. No rib fracture was seen (Fig. 1). Emergent CT examination of thorax and abdomen was performed with administration of intravenous but not oral contrast material. Bilateral lower lobe atelectasis, pleural effusion and a right adrenal hemorrhage were noted (Fig. 2). An air–fluid level was seen in the left upper quadrant, but it was not certain whether the air was free in the abdomen or whether it was contained in a herniated hollow organ in the thoracic cavity. For differentiation, CT examination was repeated following oral contrast administration. Multiplanar reconstruction was performed in coronal and sagittal planes. Post-oral-contrast images revealed opacification of the fluid-filled stomach in the left hemithorax, consistent with a diagnosis of diaphragmatic rupture and herniation of the stomach. Diaphragmatic leaflets could not be identified due to pleural effusion (Fig. 3). The patient underwent surgery and the diaphragmatic defect was repaired (Fig. 4).
Discussion Diaphragmatic injuries occur in 0.8–8% of patients who suffer blunt trauma. Nearly 90% of diaphragmatic ruptures from blunt trauma occur in motor vehicle accidents. Injuries are three times more common to the left hemidiaphragm than to the right [1, 5, 6]. The mechanisms of injury can be classified as lateral impact and frontal impact. Lateral impact distorts the chest wall and shears the diaphragm, whereas frontal impact leads to increased intraabdominal pressure [1]. Most ruptures occur at the posterolateral aspect of the hemidiaphragm between lumbar and intercostal muscle attachments, which are the weakest points of the diaphragm. The tear spreads radially and is usually longer than 10 cm.
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Fig. 1 Supine chest X-ray demonstrating elevation of left hemidiaphragm and increased opacity of left lung base. Backboard artifacts limit this chest X-ray
Fig. 3a,b CT examination with intravenous and oral contrast showing stomach in the thoracic cavity filled with oral contrast. a Axial image at nearly the same level as Fig. 2. b Coronal multiplanar reconstruction image. Volume rendering was obtained with the Advantage Windows 4.1 software (GE Medical Systems, Milwaukee, Wis.). The reformatted image shows herniation of the abdominal contents into the chest. The rupture on the left is easily seen by comparison with the right
Fig. 2 CT examination with intravenous but without oral contrast material. Axial image through the lower hemithorax showing bilateral lower lobe atelectasis and pleural effusion. Air–fluid level is seen in the left hemithorax
Associated injuries of other organs are observed in 52–100% of patients. Splenic injuries (60%), pelvic fractures (40–55%), liver, renal and thoracic injuries are the most commonly encountered [1, 6]. Chest radiographs allow diagnosis of 27–60% of leftsided and 17% of right-sided diaphragmatic injuries. Intrathoracic herniation of stomach, small bowel, and colon can be identified. Nasogastric tubes can be seen above the left hemidiaphragm. Some suggestive findings are elevation of the diaphragm and contralateral shift of the mediastinum. Hemothorax, pulmonary contusion, and atelectasis can mask diaphragmatic injury on chest radiographs, as exemplified in our case [7]. As occurred in our case, diaphragmatic rupture can be missed on chest radiographs at a rate ranging from 12% to 66% [1]. Helical CT is more valuable in the diagnosis of diaphragmatic injuries, with a sensitivity of 71% and a
Fig. 4 Photograph during surgery showing repair of ruptured diaphragm
specificity of 100% [8]. Helical CT allows rapid acquisition of volumetric data, decreasing respiratory motion artifacts and providing multiplanar reconstruction images [9]. A diaphragmatic defect can be seen in 73% of the patients with diaphragmatic rupture, but it is not specific for rupture. Congenital defects can be seen in 6% of asymptomatic adults. Intrathoracic herniation of abdominal viscera can also be suspected. The ‘‘collar
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sign,’’ which represents constriction of the viscus at the site of tear, may accompany herniation [1]. The dependent viscera sign has been more recently described by Bergin et al. and was observed in nearly 90% of the patients in their series. This refers to the fall of the herniated viscera to a dependent position against the posterior ribs in a patient during CT examination in supine position [10]. The dependent viscera sign was also seen on CT examinations in our patient. CT imaging has some limitations in visualization of the diaphragm since the axial plane is tangential to the dome of the diaphragm. Multiplanar reconstruction, especially in coronal plane, can demonstrate herniated organs and help in the diagnosis of diaphragmatic rupture. The liver, spleen, and unopacified stomach have nearly the same attenuation value as the diaphragm, making it invisible without contrast material. Hemothorax and ascites can obscure the margins of diaphragmatic rupture [1]. CT examination also has some pitfalls in the diagnosis of diaphragmatic rupture. Diaphragmatic eventration can mimic rupture. Oral and intravenous contrast must be used to identify surrounding structures in order to increase the accuracy of diagnosis. MRI is not usually used in the acute trauma setting but can be reserved for patients with an uncertain CT diagnosis or delayed signs of rupture [11, 12]. In many busy trauma centers oral contrast may not be used in emergent CT examinations, especially if major injuries are suspected and urgent scanning is needed. However, in stable patients abdominal and thoracic CT scanning with administration of oral contrast can identify traumatic diaphragmatic rupture. Especially when the diagnosis cannot be made confidently, oral contrast must be administered before CT examination.
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