Peripheral Artery Imaging by Contrast-enhanced 3D Tomographic Ultrasound

Abstract

Introduction - High quality below knee arterial imaging is essential prior to femoral-distal bypass or calf artery angioplasty [1]. Contrast-enhanced tomographic ultrasound (CEtUS) using sulphur hexafluoride (Sonovue) is a novel and entirely safe 3-D imaging modality, with no exposure to ionising radiation or nephrotoxic contrast. We compared CEtUS and angiography for imaging the arteries below the knee. Methods - Symptomatic patients investigated using CT, MR or catheter angiography prior to peripheral arterial procedures, underwent CEtUS the same week. Bolus injections of Sonovue (1.5ml) were given intra-venously with a maximum of 5mL administered/patient. CEtUS and angiography images were then compared using the validated Society of Vascular Surgery (SVS) run off score, assuming angiography to be the gold standard. Angiograms were reported by a Consultant Vascular Radiologists. Results - 191 vessels were imaged in 42 patients of median weight 78.1±13.3Kg 9 were diabetic. CEtUS was compared with 7 catheter, 13 CT and 20 MR angiograms. The mean SVS scores for the popliteal and tibio-peroneal trunk by CEtUS were 1.10±1.28 and 0.51±1.06 compared to 0.99±1.30 and 0.78±1.25 by angiography. Mean SVS score for the anterior tibial, posterior tibial and peroneal artery by CEtUS are 1.01±1.03, 1.71±1.22 and 1.46±1.32 compared to 0.68±1.01, 1.34±1.32 and 1.06±1.26 by angiography. For the Plantar arch and Dorsalis pedis the mean SVS scores by CEtUS were 2.0±2.12 and 2.0±0.0 with scores of 2.25±1.03 and 2.5±0.0 by angiography. There were 21 instances where CEtUS demonstrated severe arterial stenosis or occlusion not reported on angiography. Conversely there were 12 instances where angiography demonstrated severe stenosis or occlusion but CEtUS did not. There was a good correlation between CEtUS and the various angiogram types, r = 0.67 (95%CI 0.58–0.74), p<0.0001. Conclusion - As surgeons can see and interpret CEtUS images themselves and as CEtUS is entirely safe, CEtUS may ultimately replace peripheral angiography. CEtUS is now routinely used in our service to identify target distal arteries for reconstruction.