Quantitative coronary arteriography: improving catheter calibration by an efficient correction for differential magnification

Differential magnification of the vessel and of the scaling catheter in the X-ray field causes significant errors in calibration of imaged vessel size. To correct for differential magnification properly, laborious and costly calculations are required. The authors derived the equations of accurate correction for differential magnification. Starting from these equations the authors reduced the correction effort to the acquisition of a second complementary angiogram and two digitizing operations. The validation of this approximate procedure in computer simulations and in vitro phantom studies showed a correction for differential magnification up to 85%.