Figure 10a. Deep vein thrombosis due to antiphospholipid antibody syndrome. (a) Arterial-phase dynamic subtraction MR angiogram obtained with two separate injections of 0.05 mmol/kg of gadopentetate dimeglumine shows no occlusion of the main arteries of the lower extremity. (b) Venous image from dynamic subtraction MR angiography obtained by using double subtraction shows occlusion of the left popliteal and femoral veins (arrows).