Purpose To prospectively compare the assessment of stenosis and radiologist confidence in the evaluation of below the knee lower extremity runoff vessels between computed tomographic angiography (CTA) and contrast enhanced magnetic resonance angiography (MRA) in a cohort of 19 clinical patients. Materials and Methods Our study was HIPAA compliant and IRB-approved. 19 consecutive patients with known or suspected peripheral arterial disease were imaged with both CTA and a recently developed MRA technique performed within 24 hours of each other and prior to any therapeutic intervention. Resulting images were randomized and interpreted in blinded fashion by four board certified radiologists with expertise in CTA and MRA. Vasculature of the lower leg was apportioned into 22 segments, 11 for each leg. For each segment, degree of stenosis and confidence of diagnosis were each determined using a three-point scale. Differences between CTA and MRA were assessed for significance using pooled histograms which were analyzed using the Wilcoxon signed rank test. Results For assessment of stenosis, there was no difference in CTA vs. MRA for 20/22 segments. For confidence of diagnosis, assessment of popliteal arteries was superior on CTA compared to MRA (p<0.05). Confidence in assessment of both tibioperoneal trunks and the left proximal anterior tibial artery was not significantly different between CTA and MRA. Confidence in assessment of all other 17 segments was superior with MRA than CTA (p<0.02). Conclusion MRA using the method described here is a promising technique for evaluating lower extremity arterial runoff. MRA had an overall superior performance in radiologist confidence when compared to CTA for imaging runoff vessels below the knee.

A 59 year old non-smoker male presented with a long history of recalcitrant lower extremity ulcers. Forty years ago, he underwent splenectomy for a nonmalignant reason. Shortly after his surgery, he developed multiple collateral veins over his abdomen with extensive lower extremities venous varicosities. He was ultimately diagnosed with Budd-Chiari syndrome (BCS), classified as Budd-Chiari type I whereby the thrombus was limited to the intrahepatic inferior vena cava, not directly compromising the hepatic veins [1,2]. He was initially treated with warfarin but due to bleeding complications, this medication was discontinued. More recently, he has been plagued with chronic recurrent lower extremity ulcers. Although healing promptly with compression therapy, his clinical course was marked by frequent ulcer recurrence. He otherwise denied dyspnea or recent weight changes.Physical examination revealed a 10 cm ulcer involving the medial foreleg of the right lower extremity with hemosiderin staining and dermal sclerosis. Multiple large varices were evident on the inspection of his extremities. There was no evidence of lower extremity deep vein thrombosis on venous Doppler ultrasound. His ECHO revealed a normal left ventricular ejection fraction (68%) and normal right ventricular systolic pressure. Laboratory evaluation was negative for lupus anticoagulant, factor V Leiden and PT 20210 mutation. He had normal levels of protein C and S and there was no evidence of myelodysplasia. His initial evaluation however, also included a chest X-ray that revealed a soft-tissue prominence in the right tracheobronchial angle (Fig. 1) worrisome for malignancy. DiagnosisThe presence of an indeterminate right paratracheal mass prompted CT of the chest and abdomen to exclude malignancy. We present his CT as a pictorial demonstration of several physiologic and imaging characteristics associated with BCS. The underlying pathology of BCS is represented by occlusive calcified thrombus within the intrahepatic IVC ( Fig. 2a; thick arrow). The intrahepatic IVC occlusion results in development of extensive collateral pathways including a markedly enlarged azygous system as well as prominent hemiazygous (HA) and intercostal collateral systems (thin arrows) [3][4][5]. The indeterminate soft tissue prominence noted on the plain film of the chest was shown to be due to the marked dilatation of the azygous system in the right tracheobronchial angle ( Fig. 2b; arrow). The correlative chest CT confirmed that there was no imaging findings of lymphadenopathy or neoplasm in the chest or abdomen and the chest X-ray findings were shown to be due to physiologic changes from BCS. DiscussionWith an estimated prevalence of nearly two per million inhabitants, Budd-Chiari syndrome (BCS) is a rare disease [6,7]. BCS may have a high degree of heterogeneity A. Tafur Á W. Wysokinski Á T. Vrtiska Á R. McBane II