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The Measurement of Blood Flow Waveforms from X-Ray Angiography: Part 2: Application to Video Recordings of Digital Subtraction Angiography

A method of measuring blood flow from X-ray angiograms recorded on cine film, by obtaining contrast mass values at numerous positions along individual vessels and at multiple instants of time, has been previously reported. In the present work it was hypothesized that the signal-to-noise limitations of recordings on video tape could be overcome by recording already-subtracted angiograms from a digital subtraction angiographic (DSA) system and that the spatial resolution of video was adequate to use a similar measurement method. Validation experiments were recorded, in which flows measured using a calibrated electromagnetic flowmeter passed through tubes of 4–7 mm diameter, during injections of 2–5 ml contrast medium. The video sequences were computer analysed and produced angiographic flow measurements agreeing with the electromagnetic flows to within 5 per cent. A case study of a clinical carotid artery DSA in a patient with secondary carcinoma metastases in the brain is described. It is concluded that accurate flow measurements can be made from DSA video recordings.