Name : Abbas
Family :Arjmand Shabestari
Affiliation : Radiology Department, Modarres Hospital, SBMU
Academic Degree: Associate Professor of Radiology
Resident : Ramin Pourghorban
Gender : Female
Age : 67
67 year-old female with ischemia of lower extremities
Thoracic and abdominal contrast-enhanced CT scans reveal a large floating thrombus in thoracic descending aorta (combined Figs. 1-5). Lack of normal enhancement is depicted in a large portion of the spleen, implying splenic infarct (combined Figs. 5-8). Notice the presence of a thin peripheral rim of enhancement due to vascular supply from capsular vessels. Also noted is a wedge-shaped non-enhanced region in postero-medial part of the left kidney, in favor of renal infarct (best shown in upper-right image of Fig. 9). Atrophy of the left kidney and compensatory hypertrophy of the right kidney are also appreciated. Severe atherosclerotic changes in lower extremities were also detected (not shown).
Aortic Floating Thrombus, Aortic Dissection
Floating Thrombus in Thoracic Descending Aorta, Splenic and Renal Infarct
Discussion (Related Text)
Free Floating Thrombus (FFT) of the aorta is defined as a nonadherent part of the thrombus floating within anormal aortic lumen. This is a very rare condition with approximately 100 such cases described in the literature, and is a disease entity different from the thrombus of anatherosclerotic aorta. In general, it is unusual to find an aortic thrombus in a nonaneurysmal and non-atherosclerotic aorta. FFT of the aorta is usually associated with hypercoagulable disorders in addition to its association with malignancy, trauma, and instrumentation. Transient hypercoagulable states and turbulent blood flow have been described as the pathologic mechanisms. Tenenbaum et al. used unenhanced dual helical CT to assess calcium deposits and areas of hypoattenuation adjacent to the aortic wall in 32 patients with recent stroke or embolic events. The authors found that defining a threshold of 4-mm thickness for protruding atheromatous plaques resulted in the best sensitivity (13/15; 87%) and specificity (14/17; 82%) for CT when compared with transesophageal echocardiography. This corresponds well to the threshold of 4 mm that was found in the French Aortic Plaque in Stroke study to predict a significantly increased risk of stroke. Tenenbaum et al. also found that although unenhanced CT is suitable for screening studies, unenhanced dual-helical CT with positive results should be followed with contrast-enhanced CT or transesophageal echocardiography. Notably, the authors also reported six protruding atheromas in the upper ascending aorta and proximal arch that were overlooked on transesophageal echocardiography. These cases highlight one advantage of CT over transesophageal echocardiography: CT provides complete imaging of the thoracic aorta, whereas transesophageal echocardiography does not.
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