Evaluation of catheters and metallic catheter markers as calibration standard for measurement of coronary dimension.

Measurement of coronary dimension requires an accurate and reproducible dimensional reference. Angiographic catheters are frequently used for this purpose. We measured the angiographic diameters of a broad range of diagnostic and angioplasty guiding catheters by using two commonly used edge-detection algorithms. Angiographic diameters are significantly less than true catheter outer diameter. Therefore the use of contrast-filled catheters as a dimensional reference may lead to considerable error in vessel measurement with overestimation of absolute dimension. Tables of reference values for multiple catheter as calibration standard, tested under a variety of angiographic conditions. The metallic-tipped marker was found to have a better degree of reproducibility than catheters. These findings have implications for studies employing serial measurements of coronary artery dimension and for the clinical practice of estimating vessel diameter for choice of balloon size during angioplasty.