Placement of an inferior vena cava filter in a pig guided by high-resolution MR fluoroscopy at 1.5 T

Percutaneous placement of an inferior vena cava. filter is a means for long -term prevention of pulmonary thromboembolism. In this study we investigate d the magnetic resonance (MR) imaging properties of a Nitinol vena cava fil ter, in various anatomic and angiographic scans, as well as the feasibility of placing this filter under near real-time, high-resolution MR fluoroscop y. We made use of the passive tracking strategy, with on-line image process ing and visualization, both in vitro and in a pig. The artifacts provoked b y the metallic filter were such that the position and orientation of the fi lter were well depicted in all scans. Considerable radiofrequency caging ob scured the interior of the filter. Our experiments showed that an MR-guided vena cava filter placement, with sufficient temporal and spatial resolutio n, is possible. Three-dimensional phase contrast MRA allowed direct evaluat ion of the filter placement procedure, without the use of contrast agent. ( C) 2000 Wiley-Liss, Inc.