FOLLOW-UP MONITORING OF CAVAL FILTERS IN COLOR-CODED DUPLEX SONOGRAPHY

In 49 patients, colour-coded Duplex sonography was performed after implantation of a Greenfield caval filter. A plain film radiograph of the abdomen was taken additionally. The examination could be assessed free of artifacts in the longitudinal and transverse section in a total of 41 patients (84%). The procedure facilitates not only a diagnosis of thrombotic changes in the vena cava but can also display the topographical position of the filter and the venous flow. Caval thrombosis was verified in 5 patients. In 7 cases there was a decentral position of the filter apex with tilting. The penetration of filter struts through the vein wall eluded sonographic diagnosis as did morphological changes to the filter (e.g. filter fracture). In combination with the plain film radiograph, colour-coded Duplex sonography can replace cavography or computed tomography in the investigation of position and venous flow.