Aortic aneurysms cause weakness in the wall of the aorta and increase the risk of aortic rupture. They usually cause no symptoms, except during rupture. AAA most commonly is caused by atherosclerosis, a gradual build-up of cholesterol and scar tissue that damages the walls of blood vessels. J Ultrasound Med. Postcontrast delayed phase images may also be obtained in patients with endovascular repair of TAA or dissection (TEVAR) to assess for endoleak or in patients with inflammatory TAA/aortitis to evaluate for periadventitial enhancement indicative of active inflammation. The descending thoracic aorta extends to the diaphragmatic hiatus. The three sinuses of Valsalva taper and form a “waist” at their junction with the tubular ascending segment (ie, the sinotubular junction [STJ]). Computed tomography angiography and magnetic resonance angiography are the most commonly used techniques for thoracic aortic aneurysm diagnosis and imaging surveillance, with each having unique strengths and limitations that should be weighed when deciding patient-specific ⦠When selecting an imaging technique, the strengths and weaknesses of various imaging modalities should be considered in relation to the clinical context. Nchimi A, Defawe O, Brisbois D, Broussaud TK, Defraigne JO, Magotteaux P, Massart B, Serfaty JM, Houard X, Michel JB, Sakalihasan N. Mr imaging of iron phagocytosis in intraluminal thrombi of abdominal aortic aneurysms in humans. Thoracic aortic aneurysm (TAA) is a chronic condition that manifests as progressive dilation of the thoracic aorta resulting from degradation of the normal smooth muscle cells and extracellular matrix proteins that provide integrity to the aortic wall. An aortic aneurysm is an enlargement of the aorta to greater than 1.5 times normal size. males are much more commonly affected than females (4:1 male/female ratio) Genetically mediated TAAs are those that occur in the setting of a known clinical syndrome (eg, Marfan, Ehlers-Danlos) or in the setting of a genetic mutation in molecular pathways known to be associated with TAA (eg, transforming growth factor-β signaling pathway). 3. Right brachiocephalic A to the attachment of the ligamentum arteriosum Proximal (right brachiocephalic artery to lt subclavian A) Distal/Isthmus (lt subclavian A to attachment ⦠Imaging Presentation . Abdominal aortic aneurysm (AAA) rupture is a feared complication of abdominal aortic aneurysm and is a surgical emergency. Aortic aneurysms (AAs) are life-threatening permanent dilations of the aorta, frequently defined by a diameter of 1.5 times normal. Occasionally, there may be abdominal, back, or leg pain. An important feature seen in contained rupture of an aortic aneurysm is the draped aorta sign - in which the posterior wall of the aorta is not seen distinctly from adjacent structures, and the contour of the aorta follows that of adjacent vertebrae. Contrast-enhanced CTA of the aorta may be performed with bolus tracking or use of a timing bolus to ensure optimal enhancement of the thoracic aorta. The mortality rate is very high being > 90% 6. In part, this is caused by increasing rates of incidental detection on unrelated imaging studies (eg, lung cancer screening, coronary computed tomography angiography [CTA]/calcium scoring). Abdominal radiographs are not a sensitive mode of detection. Double-oblique measurement obtained orthogonal to the aortic centerline allows creation of a true short axis reformation of the aortic diameter and has been shown to allow more accurate measurement of aortic size compared with axial measurement ( Fig. This region is of clinical significance, because it is a common site of nonfatal traumatic aortic injury and coarctation. CT findings of rupture, impending rupture, and contained rupture of abdominal aortic aneurysms. 1. The primary management objective for TAA is to identify aortic growth early and to surgically replace the aorta before it reaches a high-risk size. Noninvasive imaging surveillance plays a central role in the management of TAA through its ability to determine maximal aneurysm diameter and monitor for growth and other complications. The American College of Radiology Appropriateness Criteria for TAA initial imaging rates CTA and MRA as “usually appropriate.” For preprocedure planning before thoracic endovascular repair (TEVAR), CTA chest, abdomen, and pelvis is rated at 9 “usually appropriate,” whereas MRA and CTA chest alone are rated at 7 “usually appropriate.” CTA is often preferable to MRA following TEVAR given the increased artifact as a result of metal stent (particularly those composed of stainless steel) and the increased ability of CTA to detect postoperative infection and endoleak. 6. However, it is difficult to assess size accurately (due to magnification effects and often poor visualization on the side of the artery). Most TAAs are classified as degenerative and associated with fusiform dilation of the ascending aorta, whereas root aneurysms are typically seen in aortic-related connective tissue disorders and descending thoracoabdominal aneurysms are strongly associated with atherosclerosis. Rakita D, Newatia A, Hines JJ et-al. They usually cause no symptoms except when ruptured. In the absence of acute complications, TAAs grow slowly over years or even decades, with typical growth rates in the range of 1 to 3 mm/y. To confirm the presence of an abdominal aortic aneurysm, a physician may order imaging tests including: Abdominal Ultrasound (US): Ultrasound is a highly accurate way to measure the size of an aneurysm. Guidelines suggest that aortic diameters be reported at specific aortic locations along the aortic length including the sinuses of Valsalva, STJ, midascending aorta, proximal and distal arch, middescending aorta, and at the diaphragmatic hiatus. A chronic rupture may escape detection for about weeks to months and are known as sealed aneurysmal rupture or spontaneously healed aneurysmal ruptureor abdominal aortic aneurysmal leak. AAA is commonly asymptomatic, and in the absence of routine screening, diagnosis is usually incidental when imaging to assess unrelated medical complaints. 6-1 to 6-4 ) . A calcified aortic aneurysm may be seen with a secondary blurring of the psoas outline in case of retroperitoneal hemorrhage. Aortic aneurysm imaging 1. High-quality aortic imaging plays a central role in the management of patients with thoracic aortic aneurysm. Incidental aortic dilation (>4.0 cm) is present in about 3% of patients greater than 55 years old. For example, a chest X-ray can show a bulging aorta. Aortic aneurysm rupture is the most important diagnosis you want to be able to exclude in patients with acute abdominal pain especially when they present with back or flank pain. Aortic Aneurysm Endograft Repair Aortic Endograft Repair is a minimally invasive procedure often used to treat aortic aneurysms. 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