title: The utility of chest X-ray as a screening tool for blunt thoracic aortic injury.
abstract: BACKGROUND
  The early and accurate identification of patients with blunt thoracic aortic injury (BTAI) remains a challenge. Traditionally, a portable AP chest X-ray (CXR) is utilized as the initial screening modality for BTAI, however, there is controversy surrounding its sensitivity. The purpose of this study was to assess the sensitivity of CXR as a screening modality for BTAI.
  
  
  METHODS
  After IRB approval, all adult (≥18 yo) blunt trauma patients admitted to LAC+USC (01/2011-12/2013) who underwent CXR and chest CT were retrospectively reviewed. Final radiology attending CXR readings were reviewed for mediastinal abnormalities (widened mediastinum, mediastinal to chest width ratio greater than 0.25, irregular aortic arch, blurred aortic contour, opacification of the aortopulmonary window, and apical pleural haematoma) suggestive of aortic injury. Chest CT final attending radiologist readings were utilized as the gold standard for diagnosis of BTAI. The primary outcome analyzed was CXR sensitivity.
  
  
  RESULTS
  A total of 3728 patients were included in the study. The majority of patients were male (72.6%); mean age was 43 (SD 20). Median ISS was 9 (IQR 4-17) and median GCS was 15 (IQR 14-15). The most common mechanism of injury was MVC (48.0%), followed by fall (20.6%), and AVP (16.9%). The total number of CXRs demonstrating a mediastinal abnormality was 200 (5.4%). Widened mediastinum was present on 191 (5.1%) of CXRs, blurred aortic contour on 10 (0.3%), and irregular aortic arch on 4 (0.1%). An acute aortic injury confirmed by chest CT was present in 17 (0.5%) patients. Only 7 of these with CT-confirmed BTAI had a mediastinal abnormality identified on CXR, for a sensitivity of 41% (95% CI: 19-67%).
  
  
  CONCLUSIONS
  The results from this study suggest that CXR alone is not a reliable screening modality for BTAI. A combination of screening CXR and careful consideration of other factors, such as mechanism of injury, will be required to effectively discriminate between those who should and should not undergo chest CT.
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Adam
authors: A
authors: Gutierrez
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA. Electronic address: kenji.inaba@med.usc.edu.
authors: Kenji
authors: K
authors: Inaba
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Stefano
authors: S
authors: Siboni
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Zachary
authors: Z
authors: Effron
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Tobias
authors: T
authors: Haltmeier
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Paul
authors: P
authors: Jaffray
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Sravanthi
authors: S
authors: Reddy
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Alexander
authors: A
authors: Lofthus
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Elizabeth
authors: E
authors: Benjamin
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Joseph
authors: J
authors: Dubose
authors: Division of Trauma and Surgical Critical Care, Department of Surgery, LAC+USC Medical Center, University of Southern California, Los Angeles, CA 90033, USA.
authors: Demetrios
authors: D
authors: Demetriades
mesh_terms: D000328:Adult; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging* / Q000293:injuries; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D013902:Radiography, Thoracic; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013898:Thoracic Injuries / Q000000981:diagnostic imaging*; D014481:United States / Q000453:epidemiology; D014949:Wounds, Nonpenetrating / Q000000981:diagnostic imaging*
keywords: Blunt thoracic aortic injury; Chest X-ray; Screening; Sensitivity; Trauma