Relationship between the pixel value in digital subtraction angiography and iodine concentration: Study in high iodine concentration with original phantom

Quantitative digital subtraction angiography (DSA) image analysis based on densitometry is widely accepted and used. For the densitometoric DSA image analysis, it is required that there is a linear relationships between the p ixel values on DSA images (DSA values) and contrast medium iodine concentra tion or the thickness of the vessels or the chambers filled with contrast m aterial. We studied on relationship between the DSA value and iodine concen tration especially in high iodine concentration. as for the relationship be tween DSA values and iodine concentration on the DSA images at low concentr ation, DSA phantom had a good linear relationship. However, the relationshi p at the high iodine concentration, DSA phantom some times lost this linear relationship. Our results suggested that it was necessary to identify rela tionship between DSA values and iodine concentration in each DSA system, es pecially in high iodine concentration setting, for densitometoric DSA image analysis.