Imaging modalities for the early diagnosis of acute aortic syndrome

Abstract

The term acute aortic syndrome (AAS) incorporates aortic dissection, intramural haematoma, and penetrating atherosclerotic ulcer. The common feature of these entities is disruption of the medial layer of the aortic wall. Owing to the life-threatening nature of these conditions, prompt and accurate diagnosis is of paramount importance--misdiagnosis can be fatal. The noninvasive imaging techniques that have a fundamental role in the diagnosis and management of patients with AAS include CT, MRI, transoesophageal echocardiography (TEE), and transthoracic echocardiography (TTE). CT is the most-commonly used imaging modality owing to its wide availability, accuracy, and large field of view. CT plus TTE is the best combination for diagnosing AAS and its complications, and allows important morphological and dynamic aspects of AAS to be assessed and appropriately managed. Ideally, TEE should be performed immediately before surgery or endovascular treatment, in the operating theatre and under general anaesthesia. In stable patients with an uncertain diagnosis of intramural haematoma despite high clinical suspicion, MRI is the technique of choice to make a definitive diagnosis. Imaging techniques have an important role in the primary diagnosis, treatment strategy, and risk stratification of patients with AAS.

MDCT evaluation of acute aortic syndrome (AAS)

“…5,6,11,63 There is currently no clear cut-off for PAU diameter (depth) or neck diameter that warrants treatment; in one publication, a depth of .20 mm or a neck .10 mm was associated with higher complication rates. 64,65 On MDCT, localized ulceration penetrating through the aortic intima is the characteristic finding. There is also an outpouching of the outer aortic contour, which differentiates uncomplicated atheromatous ulcer from PAU.…”

Presentation, Diagnosis, and Outcomes of Acute Aortic Dissection

“…Many patients with AAD are diagnosed and treated as having acute coronary syndrome, which is a much more frequent condition than AAD. Advanced imaging, especially CT, has been employed with increasing frequency in emergency departments for the "triple rule out," but whether this practice has improved the diagnosis of AAD is unknown (17). Advanced imaging, especially CT, has been employed with increasing frequency in emergency departments for the "triple rule out," but whether this practice has improved the diagnosis of AAD is unknown (17).…”

Penetrating aortic ulcer manifesting as atypical chest pain

“…A penetrating aortic ulcer (PAU) is characterized by an atherosclerotic plaque that penetrates the internal elastic lamina into the aortic media and allows hematoma formation within the aortic wall. Together with aortic dissection and intramural hematoma, it is one of the three acute aortic syndromes (AAS) [1]. When viewed tangentially, a PAU classically appears as a craterlike outpouching of the aortic lumen associated with atheroma.…”