Transabdominal Sonography in the Diagnosis of Acute Aortic Dissection Involving the Abdominal Aorta

Objective: Despite major advances in imaging techniques, correct diagnosis of acute aortic dissection is frequently missed. Although as many as one-third of acute cases of aortic dissection involve the abdominal aorta, emergency physicians rarely suspect this lethal disease in patients presenting with abdominal pain. Transabdominal sonography is typically employed by emergency physicians, but there are few studies investigating this application in diagnosing acute aortic dissection. Methods: Between January 2001 and December 2004, 21 patients who presented with abdominal pain under suspicion of acute aortic dissection involving the abdominal aorta were enrolled in this study. Each patient underwent CT scanning and transabdominal sonography to identify an intimal flap in the abdominal aortic lumen. Whether a CT scan or transabdominal sonography was employed first depended on emergency physician preference. Result: Of these 21 patients, 4 patients (19%) who presented with abdominal pain were initially diagnosed with acute aortic dissection using transabdominal sonography, and then underwent CT scans. Seventeen patients (81%) underwent CT scans directly under the impression of aortic dissection prior to transabdominal sonography. Examination with transabdominal sonography for all 21 patients did not provide a clear view of the abdominal aorta in 4 patients (19%) due to anatomical limitations. Suspicion of an intimal flap in the abdominal aorta was identified in 17 patients (81%) on transabdominal sonography, but 1 of these 17 patients had no visible intimal flap in the aorta on the CT scan. Conclusion: Transabdominal sonography is convenient in EDs. In patients with abdominal pain, we must emphasize that acute aortic dissection needs to be included in the differential diagnosis of abdominal pain when performing transabdominal sonography.