Chapter30 Aorta

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Chapter 30: Thoracic Aorta

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Figure 30.56.  Takayasu Arteritis. Axial CT image at the level of the left coronary cusp ( A ) in a 39-year-old woman demonstrates irregular wall thickening along the descending aorta ( arrows ). Axial balanced steady state free precession (bSSFP) ( B ) and contrast-enhanced T1-weighted ( C ) MR images at the same level demonstrate irregular, hyperintense wall thickening with enhancement ( arrows , noncontrast T1 image not shown). Axial fused PET-CT image at the same level ( D ) demonstrates corresponding increased uptake that has been shown to correlate with active disease.

tumors include leiomyosarcomas, hemangioendotheliomas, fibrosarcomas, myxoid sarcomas, and angiosarcomas. Tumors can also be characterized by their location—that is, intra- or extraluminal/periaortic. Mural plaques in atherosclerosis and intramural thrombus associated with aneurysm are easily diagnosed when seen in the classic setting and with classic features—for example, a circumferential, smooth appearance. Focal, eccentric mural thrombus is less common but may be more difficult to dif- ferentiate from tumor, especially in the absence of associated atherosclerotic disease. Most aortic tumors are sarcomas and will typically mani- fest on both CT and MR as an eccentric, pedunculated, and/ or lobulated intramural filling defect (Fig. 30.57). Postcon- trast enhancement may be absent or difficult to detect adja- cent to bright intraluminal contrast. Subtraction images, more commonly performed with MR, can be invaluable in this setting to make subtle enhancement more apparent. An

extraluminal tumor often appears on CECT and MR as an enhancing periaortic soft tissue rind that may be confused for a contained aortic rupture; lymphoproliferative disorder, for example, lymphoma; or inflammatory process, for example, retroperitoneal fibrosis. In addition to primary cardiac tumors, tumors can embo- lize into the aorta. This can occur with a primary cardiac tumor, such as an atrial myxoma (Fig. 30.58). In addition, lung cancers and pulmonary metastases can invade into the left atrium through the pulmonary veins and embolize into the aorta or its branches. Conclusion Imaging plays a vital role in evaluation of the thoracic aorta, in delineating anatomy and anatomic variants, as well as in diag- nosing the full spectrum of thoracic aortic disease including

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Figure 30.57.  Aortic Sarcoma. Axial CT image at the level of the left pulmonary artery ( A ) and oblique sagittal reformat ( B ) in a 61-year-old woman demonstrate irregular mass-like thickening along the descending aorta ( arrows ) representing primary aortic sarcoma.