Digital subtraction angiography using a temporal bandpass filter: associated patient motion properties

A system for performing real-time digital angiography both intraarterially and intravenously is described. A filtering process, rather than mask subtraction produces diagnostic-quality angiograms using existing fluoroscopic x-ray systems operated continuously (30 frames/sec) at less than 70 kVp and 20 mA. The image degradation effects of patient motion (breathing, swallowing, sudden movement) are dealt with differently from a subtraction approach. Certain periodic patient motions can be accommodated without the need for postprocessing. An analysis of experimental and clinical results of intravenous angiographic studies is presented, with emphasis on patient motion properties.