Figure 12c. (a) Axial contrast-enhanced CT scan shows fluid in the anterior portion of the superior aortic recess (arrow), a finding that can sometimes be mistaken for aortic dissection. A small amount of fluid is also seen posterior to the ascending aorta (A) in the posterior portion of the superior aortic recess (arrowhead). (b) Axial contrast-enhanced CT scan obtained cephalad to a shows the superior extension of the superior aortic recess (arrowhead), which now lies in a right paratracheal location. Fluid in this location can be mistaken for an enlarged lymph node. (c) Coronal reformatted image from CT data shows the superior extension of the superior aortic recess (arrowhead) lateral to the aorta (A). Fluid (arrow) is also identified in the anterior portion of the superior aortic recess between the aorta and the main pulmonary artery (PA). (d) Sagittal reformatted image from CT data again shows the superior extension of the superior aortic recess (arrowhead). SVC = superior vena cava, T = trachea.