title: The placement of vena cava umbrella filters. The value of phlebography.
mesh_terms: D005069:Evaluation Studies as Topic; D005374:Filtration; D006801:Humans; D008297:Male; D008875:Middle Aged; D010690:Phlebography; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000517:prevention & control*; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging*