Adjustable sliding aluminum wedge filter: device for angiographic enhancement

Since the human body is of neither uniform thickness nor uniform composition, opacified vessels may be optimally exposed on a portion of the radiograph and overexposed on an adjacent portion. This unwanted nonuniformity in image darkness can be eliminated or reduced using a so-called compensating filter. In this paper such a filter in the form of an adjustable sliding aluminum wedge, that has been employed in angiographic procedures in our laboratory for the past four years, is described. The application of this filter to angiograms of various body parts is illustrated with clinical examples.