Imaging acute dissection of the thoracic aorta

Acute dissection of the thoracic aorta is a life-threatening condition and early diagnosis is mandatory. The determination of ascending or aortic arch involvment is essential. Although aortography has long been considered as the “gold standard” (despite the associated risks of being an invasive study), this status is presently supplanted by the introduction of three newer techniques (transesophageal echocardiography, computed tomography, magnetic resonance imaging). Transesophageal echo-cardiography, because of its high accuracy (diagnostic in 90% of cases) , safety, and speed may be considered first in cases of suspected dissection. Multiplane transesophageal echocardiographic probes allow better diagnostic accuracy, better visualization of the site of entry tear (or tears), and improvement in diagnostic specificity. Spiral computed tomography is also an accurate investigation for the diagnosis and determination of the full extent of aortic dissection. Computed tomography may be perf ormed first when transesophageal echocardiography is not readily available, but is usually undertaken secondly in order to complete the echocardiographic study. Magnetic resonance imaging, highly accurate for diagnosis of aortic dissection is also the “gold standard” in cases of intramural hemorrhage. On the other hand, this procedure is more often poorly available and less desirable for patients requiring particularly close monitoring.