Left atrial appendage clot

68 yo M with h/o mitral stenosis, atrial fibrillation and poor medical compliance presents with acute onset of bilateral leg pain. On exam, both feet were pulse-less. CTA confirmed bilateral popliteal artery occlusion, with an acute appearance.

Images from the lower chest obtained as part of CTA show enlarged left atrium. Conventional CT image shows layering low density material in the left atrial appendage. On spectral analysis, this is consistent with clot, showing no iodine uptake.

Volume rendered image from CTA showing bilateral popliteal artery occlusion

Conventional CT with filling defect in left atrial appendage, clot vs mixing artifact

Iodine map shows no iodine uptake in filling defect, consistent with clot

Fusion image nicely demonstrates lack of iodine uptake in clot