2010 Volume 21 Issue 1 Pages 17-27
Prior to surgery or endovascular therapy for the lower extremity varicose veins or deep vein thrombosis (DVT), conventional dynamic ascending phlebography provides useful information. Under tourniquet contrast media injected from dorsal pedis vein reveals DVT, incompetent perforators (IP) and refluxed superficial varicose veins after stepping. But overlapping superficial veins are very complex and confusing with IP, and it is invasive because of radiation exposure and the use of nephrotoxic and allergic iodinated contrast media. Although computed tomography (CT) with volume rendering (VR) demonstrates superficial varicose veins without contrast media, IP or deep venous system cannot be depicted. On the other hand, magnetic resonance (MR) imaging using steady state free precession (SSFP) in the semispine position can reveal the varicose veins on the muscle fascia on VR and the perforating and deep veins can be identified on maximum intensity projection (MIP) and multiplanar reconstructions (MPR). For DVT, direct thrombus imaging (DTI) using fat suppressed 3D coronal inversion recovery- prepared blood suppressed gradient echo sequence demonstrates fresh clots as high signal intensity, and gadolinium administration depicts clots as filling defects on MPR or the soap bubble (SB)-MIP. MIP with SB also enables the diagnosis of postthrombotic syndrome with mural thrombosis, stenotic/occluded vessels and secondary varicose veins. Similarly, acute pulmonary thromboembolism (APTE) can be diagnosed by MR. However, CT pulmonary arteriography and venography (CT-PAV) can provide faster and more differential diagnoses. Pulmonary arteriography using balloon or pigtail- based catheters is now limited for endovascular therapies including thromboaspiration, fragmentaion, thrombolysis etc.
