The diagnostic accuracy of the mediastinal width on supine anteroposterior chest radiographs with nontraumatic Stanford type A acute aortic dissection

BACKGROUND: Nontraumatic Stanford type A acute aortic dissection is a life‐threatening condition; thus, the ability to make a precise diagnosis of nontraumatic Stanford type A acute aortic dissection is essential for the emergency physician. Several reports have shown that the mediastinal widening on a chest radiograph is useful for the diagnosis of nontraumatic Stanford type A acute aortic dissection; however, the exact cutoff value of the mediastinal width on plain radiographs is rarely defined. METHODS: A single‐center retrospective case‐control study was conducted between October 1, 2013, and March 31, 2015. We evaluated the maximal mediastinal width of the anteroposterior chest X‐ray at the level of the aortic knob in the supine position between patient groups with and without nontraumatic Stanford type A acute aortic dissection. RESULTS: We enrolled 72 patients (36 patients with nontraumatic Stanford type A acute aortic dissection and 36 patients without nontraumatic Stanford type A acute aortic dissection). The median mediastinal width of patients with nontraumatic Stanford type A acute aortic dissection was significantly larger than that of patients without nontraumatic Stanford type A acute aortic dissection (100.7 mm vs 77.7 mm, P < .01). The optimal cutoff level was 87 mm (sensitivity, 81%; specificity, 89%). Using multivariable logistic regression, the odds ratio of a mediastinal width of >87 mm for a diagnosis nontraumatic Stanford type A acute aortic dissection was 57.1 (95% confidence interval, 11.2‐290.2). CONCLUSION: A mediastinal width of >87 mm showed high sensitivity in the diagnosis of probable nontraumatic Stanford type A acute aortic dissection.