MDCT evaluation of acute aortic syndrome (AAS)

Abstract

Non-traumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. There is a common pathway for the various manifestations of AAS that eventually leads to a breakdown of the aortic intima and media. Improvements in biology and health policy and diffusion of technology into the community resulted in an associated decrease in mortality and morbidity related to aortic therapeutic interventions. Hybrid procedures, branched and fenestrated endografts, and percutaneous aortic valves have emerged as potent and viable alternatives to traditional surgeries. In this context, current state-of-the art multidetector CT (MDCT) is actually the gold standard in the emergency setting because of its intrinsic diagnostic value. Management of acute aortic disease has changed with the increasing realization that endovascular therapies may offer distinct advantages in these situations. This article provides a summary of AAS, focusing especially on the MDCT technique, typical and atypical findings and common pitfalls of AAS, as well as recent concepts regarding the subtypes of AAS, consisting of aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and unstable aortic aneurysm or contained aortic rupture. MDCT findings will be related to pathophysiology, timing and management options to achieve a definite and timely diagnostic and therapeutic definition. In the present article, we review the aetiology, pathophysiology, clinical presentation, outcomes and therapeutic approaches to acute aortic syndromes.

Acute Aortic Syndrome: Recent Trends in Imaging Assessment Using Computed Tomography Angiography

“…On the other hand, in patients with severe atherosclerotic disease, rupture of a PAU or atherosclerotic plaque can result in intimal-medial injury and bleeding into the media [37]. Thus, the current opinion regarding IMH is that it can be a variant of or a precursor to aortic dissection with a small intimal defect and thrombosed false lumen without a re-entry tear [31,37]. The clinical presentation of IMH is similar to that of aortic dissection; thus, image-guided evaluation is essential for accurate diagnosis.…”

“…5). Several specific findings aid in the identification of a false lumen, such as the cobweb sign (residua of incompletely sheared media) or beak sign (acute angle between the dissecting flap and outer wall) [14,21,30,31]. The pulsation artifact is the most common cause of a pseudodissection in the thoracic aorta [32].…”

“…Since the retrospective ECG-gated CT scan technique significantly increases the radiation dose, various techniques for reducing the radiation dose should be considered, such as using a low tube voltage, ECG-based tube current modulation, automatic exposure control, and iterative reconstruction [31].…”

Difficulties in Diagnosis and Ways to Optimize Computed Tomography in Acute Aortic Lesions

“…Изначально ОАС включал в себя группу острых нетравматических поражений аорты, а именно: расслоение аорты (РА), интрамуральную гема-тому (ИМГ) и пенетрирующую атеросклеротиче-скую бляшку (ПАЯ). В последующем сюда же были отнесены разрыв аневризмы аорты при ее нестабильности, а также травматический раз-рыв аорты при закрытой травме [5][6][7][8][9]. Патофи-зиологические механизмы развития всех упо-мянутых выше состояний отличаются, и в настоящее время мы знаем, что такие заболе-вания могут встречаться изолированно, а в не-которых случаях могут сосуществовать.…”

“…Известно, что современная многосрезовая КТ обладает высоким простран-ственным и временным разрешением, а чув-ствительность и специфичность методики по данным многочисленных исследований при-ближаются практически к 100% [5,6,8,10,11].…”