Quantitative digital subtraction angiography: two scanning techniques for correction of scattered radiation and...

Scattered radiation and veiling glare in digital subtraction angiography degrade contrast signals in a nonlinear and nonuniform way. This effect prohibits direct use of image data for accurate iodine measurement or energy subtraction imaging. Two techniques based on the use of scanning lead bars were proposed to measure the spatial distribution of scattered radiation and veiling glare in the unprocessed image data. With either technique, signals behind the lead bars were used to estimate the scatter-glare component and remove it from the image data. The scanning-lead-bar techniques can be used to reduce the scatter-glare component by a factor of up to 10. The scatter-glare correction leads to the recovery of degraded contrast signals and achieves reasonable linearity, uniformity, and consistency in the contrast measurement.