Analysis on the Reproducibility of Serial Quantitative Coronary Angiograms

For accurate analysis of serial coronary angiograms in a given patient over time, it is important to acquire paired angiograms recorded in exactly the same condition. Using the automatic gantry setting, we evaluated the geometric reproducibility of coronary angiograms and the reproducibility of vessel measurements in serial quantitative coronary angiography. Coronary angiograms of 40 patitents who underwent PTCA were analyzed before PTCA, after PTCA (medium-term) and at follow-up (long-term). The geometric reproducibility of coronary angiograms was assessed by comparing 120 angles between the major coronary branches. Reproducibility on vessel analysis was evaluated by measuring the minimal lumen diameter (MLD) of 120 non-dilated segments. Differences in the angles of the X-ray gantry were small and the standard deviation of the differences was not more than 0.5 degrees. The differences in the measurements of the angles between the major coronary branches were 0.1 ± 1.2 degrees in the same frame pre-PTCA, 0.1 ± 3.4 degrees between pre- and post-PTCA, and 0.8 ± 4.7 degrees between pre-PTCA and at follow-up. The differences in MLD were 0.01 ± 0.10, 0.01 ± 0.17, and 0.05 ± 0.19 mm, respectively. The automatic gantry setting provides good reproductibility of the X-ray imaging position. However, the geometric reproducibility of coronary angiograms and the reproducibility of vessel measurements show some variability in the medium- and long-term. This variability seems to be affected by uncontrollable factors such as heart motion or respiration