Recent progress in quantitative coronary angiography

The recent progress of quantitative coronary angiography (QCA) has paralleled our advances in interventional cardiology and has contributed significantly to our current understanding of coronary artery disease. QCA offers a scientific medium for the study of acute procedural results and serial changes over long term follow up. Changes in the absolute minimal luminal diameter (MLD) have been utilized for the study of acute luminal gain and subsequent restenosis following coronary interventional procedures and changes in both the minimal and the mean luminal diameter (MEAN) have been utilized for the study of progression/regression of coronary artery disease. While there has been a growth in the deployment of videotape as a recording medium ml account of the recent development of digital acquisition systems, the suitability of video recordings for QCA has not been established. To estimate the reliability of angiographic images recorded on videotape, experimental and clinical angiograms were recorded simultaneously on both 35 mm cinefilm and videotape with normal images and with edge enhancement on a digital angiographic system. In the experimental phantom study, cinefilm gave the closest values to true phantom diameter as compared with videotape with normal recording and edge enhancement. In the clinical study, edge enhancement on cinefilm improved accuracy, precision and correlation more than on videotape with normal images. It is concluded that cinefilm is still the most reliable recording medium for quantitative angiographic analysis in scientific studies, while edge enhancement in a digital angiographic system may improve accuracy and precision of luminal quantification in video recording. With the advent of complementary or competitive imaging modalities for coronary luminal quantification, defence by cinefilm based QCA of its title 'the gold standard' for scientific research and subsequent growth of its role in clinical practice will become critically dependent upon the demonstration of superior reliability of QCA measurements obtained by cinefilm.