In addition to an occlusive IVC or iliac vein lesion, these cases also show signs of delayed or incomplete recanalization of the pelvic and lower extremity deep veins with extensive intraluminal changes. In both the above types, primary focus should be on anatomy to accurately identify stenosis and occlusion related to outflow obstruction [9]. Gadolinium-enhanced MRV with contrast seems to be the examination of choice because of the high intravascular enhancement and acquisition of isotropic voxels with a high spatial resolution allowing for evaluation of subtle changes. Three-dimensional volumetric imaging is preferred over MR direct thrombus or time-of-flight subtraction angiography because surrounding soft tissue should be visible to identify causes of stenosis or occlusion [9]. Pascarella and Shortell [6] believe that imaging of IVC and iliac veins when there is a history of persistent venous ulcers or duplex US evidence of iliocaval obstruction. These findings include diffuse venous reflux, nonphasic common femoral vein velocity spectral waveforms, and reduced flow augmentation with distal thigh compression. US Duplex Doppler Lower Extremity It is widely agreed upon that duplex US should be the first assessment of the lower extremity venous system [1,9,14]. Duplex US is currently the most common technique because of its noninvasiveness [20]. Duplex US evaluation should additionally include condition of the deep venous system, GSV, SSV, and accessory saphenous veins. Presence and location of clinically relevant perforating veins and extent of possible alternative refluxing superficial venous pathways should also be included in any duplex US evaluation [1]. Though duplex US is widely considered the reference standard in evaluation of DVT, Hua et al [10] demonstrates that invasive preoperative venography is necessary before intervention to clarify the nature of disease and guide therapy. It is difficult to evaluate iliac vein involvement using this modality [73].
Lower Extremity Chronic Venous Disease. In addition to an occlusive IVC or iliac vein lesion, these cases also show signs of delayed or incomplete recanalization of the pelvic and lower extremity deep veins with extensive intraluminal changes. In both the above types, primary focus should be on anatomy to accurately identify stenosis and occlusion related to outflow obstruction [9]. Gadolinium-enhanced MRV with contrast seems to be the examination of choice because of the high intravascular enhancement and acquisition of isotropic voxels with a high spatial resolution allowing for evaluation of subtle changes. Three-dimensional volumetric imaging is preferred over MR direct thrombus or time-of-flight subtraction angiography because surrounding soft tissue should be visible to identify causes of stenosis or occlusion [9]. Pascarella and Shortell [6] believe that imaging of IVC and iliac veins when there is a history of persistent venous ulcers or duplex US evidence of iliocaval obstruction. These findings include diffuse venous reflux, nonphasic common femoral vein velocity spectral waveforms, and reduced flow augmentation with distal thigh compression. US Duplex Doppler Lower Extremity It is widely agreed upon that duplex US should be the first assessment of the lower extremity venous system [1,9,14]. Duplex US is currently the most common technique because of its noninvasiveness [20]. Duplex US evaluation should additionally include condition of the deep venous system, GSV, SSV, and accessory saphenous veins. Presence and location of clinically relevant perforating veins and extent of possible alternative refluxing superficial venous pathways should also be included in any duplex US evaluation [1]. Though duplex US is widely considered the reference standard in evaluation of DVT, Hua et al [10] demonstrates that invasive preoperative venography is necessary before intervention to clarify the nature of disease and guide therapy. It is difficult to evaluate iliac vein involvement using this modality [73].