초록 ▼

Difference images, derived from an X-ray image of an anatomical subject, are produced in real time by directing X-rays through the anatomical subject to produce an X-ray image, converting the X-ray image into television fields comprising trains of analog video signals, converting the analog video si

Difference images, derived from an X-ray image of an anatomical subject, are produced in real time by directing X-rays through the anatomical subject to produce an X-ray image, converting the X-ray image into television fields comprising trains of analog video signals, converting the analog video signals into digital video signals, producing integrated mask digital video signals by integrating the digital video signals over a mask time interval, subtracting the integrated mask digital video signals from corresponding digital video signals of television fields subsequent to the mask time interval and thereby producing digital difference video signals, converting the digital difference video signals into analog difference video signals, and converting the analog difference video signals into a series of visible television difference images representing changes in the X-ray image subsequent to the mask time interval. The mask time interval preferably corresponds generally to at least one complete cardiac cycle of the anatomical subject. An X-ray contrast medium is preferably injected into a peripheral blood vessel of the anatomical subject, with a timing such that the contrast medium appears in the X-ray image subsequent to the mask time interval. In another embodiment, the integrated mask digital video signals are reconverted to analog form and are subtracted on an analog basis from the analog video signals produced subsequent to the mask time interval, to produce the analog difference video signals.

대표청구항 ▼

A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through the anatomical subject for producing an X-ray image, converting said X-ray image into television fields comprising trains of analog video signals, co

A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through the anatomical subject for producing an X-ray image, converting said X-ray image into television fields comprising trains of analog video signals, converting said analog video signals into digital video signals, producing integrated digital video signals by integrating said digital video signals over a predetermined time interval corresponding to a plurality of successive television fields, producing digital difference video signals by performing a substraction between the digital video signals for a selected time different from said time interval and the corresponding integrated digital video signals, converting said digital difference video signals into analog difference video signals, and converting said analog difference video signals into visible television difference images representing changes in the X-ray image.