Three-D localization of the coronary segment and calibration catheter to correct for differential magnification in quantitative coronary angiography

The objective was to quantify the measurement errors of the major coronary segments resulting from nonidentical radiographic magnification of the segment and calibration catheter. The 3D location of 468 coronary segments and of the corresponding coronary catheter tip were assessed using biplane angiography and known projection data. The potential measurement error was then calculated in tabular form by simulating viewing angles over the full range of angiographic projections. Rotation from RAO to LAO results in a mean error changing from -4% to +5% for the RCA and from +5% to -6% for the LAD and LCx arteries. Error diagrams were established from which the potential diameter error for each CASS defined coronary segment in each specific projection may be taken from. In monoplane quantitative coronary angiography, the accuracy of catheter calibration may be improved using error diagrams. The correction should be performed simultaneously with other sources of error