Patent ID: 6754522
Filing Date: 2004-06-22
Classification: A61B

Abstract:
A method of angiographically imaging a portion of a patient's vascular system, comprising the steps:(i) producing a first sequence of masking images of said portion of the patient's vascular system; (ii) determining the masking image in said sequence having a minimum change over its immediately preceding masking image in said sequence; (iii) injecting a contrast material into the patient's vascular system; (iv) producing a corresponding sequence of contrast images of said portion of the patient's vascular system while containing said contrast material; and (v) subtracting from each contrast image of said sequence the corresponding masking image in the sequence, starting with said minimum change masking image, to thereby produce a difference image having an enhanced contrast-to-noise ratio (CNR); wherein in step (ii) a pixel-by-pixel comparison of the gray-level of the pixels in the respective masking image is made with the corresponding pixels in the preceding masking image of the sequence, and the masking image of the sequence having minimum changes over its immediately preceding masking image in the sequence is selected as said masking image of minimum change.