As discussed above, this modality is unable to provide an assessment of wall enhancement, which is an important marker in many inflammatory conditions. Similar to unenhanced CT, MRA without IV contrast is able to identify aneurysms, edema, perivascular stranding, gas, and disrupted calcifications that may be associated with aortic infections [50]. For suspected neoplasms, an irregular soft-tissue structure may be identified that may or may not enhance after IV contrast administration [46,47]. Radiography Chest Chest radiography may be helpful in evaluating the contour, size, and location of the thoracic aorta and the great vessels, which, if abnormal, would prompt further investigation [10,21]. Radiography is not considered an adequate modality to evaluate for inflammatory, infectious, neoplastic, or metabolic aortic diseases. Vascular duplex US can identify vascular wall thickening, which is an important marker in patients with generalized vascular inflammation [74], GCA [73,75], Behcet disease [76], and Takayasu arteritis [44]. Additionally, US is better than catheter-based angiography for detecting stenoses, occlusions, and aneurysms from Takayasu arteritis [44]. Nonetheless, it must be remembered that these evaluations primarily focused on nonaortic vessels. In fact, one study compared duplex US to FDG-PET/CT for the detection of extracranial large vessel vasculitis and found that US was only 26% sensitive for detecting aortic involvement. Other authors have also recognized the limitations of US for measuring wall thickness of the aorta [44,75]. For suspected neoplastic processes, US is of little value because it is not able to reliably differentiate between malignant and benign tissue [50]. There is no relevant literature available to examine the use of US in suspected aortic infection.
Nontraumatic Aortic Disease. As discussed above, this modality is unable to provide an assessment of wall enhancement, which is an important marker in many inflammatory conditions. Similar to unenhanced CT, MRA without IV contrast is able to identify aneurysms, edema, perivascular stranding, gas, and disrupted calcifications that may be associated with aortic infections [50]. For suspected neoplasms, an irregular soft-tissue structure may be identified that may or may not enhance after IV contrast administration [46,47]. Radiography Chest Chest radiography may be helpful in evaluating the contour, size, and location of the thoracic aorta and the great vessels, which, if abnormal, would prompt further investigation [10,21]. Radiography is not considered an adequate modality to evaluate for inflammatory, infectious, neoplastic, or metabolic aortic diseases. Vascular duplex US can identify vascular wall thickening, which is an important marker in patients with generalized vascular inflammation [74], GCA [73,75], Behcet disease [76], and Takayasu arteritis [44]. Additionally, US is better than catheter-based angiography for detecting stenoses, occlusions, and aneurysms from Takayasu arteritis [44]. Nonetheless, it must be remembered that these evaluations primarily focused on nonaortic vessels. In fact, one study compared duplex US to FDG-PET/CT for the detection of extracranial large vessel vasculitis and found that US was only 26% sensitive for detecting aortic involvement. Other authors have also recognized the limitations of US for measuring wall thickness of the aorta [44,75]. For suspected neoplastic processes, US is of little value because it is not able to reliably differentiate between malignant and benign tissue [50]. There is no relevant literature available to examine the use of US in suspected aortic infection.