ANGIOGRAPHIC METHOD

Angiographic process utilizing contrast mediums for the roentgenographic representation of living organ vessels, especially human, wherein a blank photograph is made of a vascular region to be visualized, a contrast medium is infused into said vascular region, a photograph of the same region is produced after a given time interval, for example 0.5 seconds, and a visual image is produced by photographic subtraction of the two pictures, whereby the quantity of the contrast medium and the X-ray dose used to produce the pictures are reduced by photographically equivalent factors to such an extent that the desired information lies in a density range (blackening range) unsuited to direct observation, and whereby in the process of photographic subtraction the density range containing the information is extracted and transposed onto a visual density range suitable for direct observation of the image.