Magnification Spot Radiographs Improve Assessment for Inferior Vena Cava Filter Fractures prior to Removal Compared to CT.

Abstract

To determine if magnification spot radiographs acquired before attempting inferior vena cava (IVC) filter removal have value in the assessment for filter fractures. A retrospective review of complex IVC filter removals performed at a tertiary referral center from October 2015 to May 2017 was performed. Magnification spot radiographs (frontal and at least 2 oblique views) were obtained with the fluoroscopic unit in the procedure suite prior to venous access for filter removal. Patients were included in the study if a computed tomography (CT) scan of the abdomen/pelvis before filter removal was available. Ninety-six patients (47 women and 49 men) were included. Most removed filters were the Recovery/G2/G2X/Eclipse/Meridian (n= 28), the Günther Tulip (n= 26), and the Celect/Celect Platinum (n= 22). Blinded review of the pre-procedural CT scans and spot radiographs for the presence of filter fractures was performed by 2 interventional radiologists. Accuracy of each modality was assessed using the status of the explanted filter as the gold standard. Agreement between the 2 readers was assessed with the kappa statistic. Fractures were present in 27 explanted filters (28%). Accuracy of CT was 88% and 68% for readers 1 and 2, respectively, which increased to 98% and 97% with magnification spot radiographs. The kappa statistic was 0.12 for CT and 0.97 for spot radiographs. Magnification spot radiographs acquired before attempting IVC filter removal improve detection of filter fractures and agreement among interventional radiologists. Therefore, these should be performed routinely to allow for optimal treatment planning.