Accuracy and precision of online quantitative coronary angiography with automatic calibration: a pilot study

Background

The objective of this study was to evaluate the degree of accuracy, precision, correlation, and agreement between the measurements performed by online Quantitative Coronary Angiography (QCA) software with automatic calibration.

Methods

Pilot study that analyzed angiographic images of ten patients through online QCA software using Auto ISO (automatic calibration isocenter) and Auto TOD (Table-to-Object Distance) automatic calibration. Catheter size was measured by both methods and the reference diameter was computed. These measurements were compared with the measurement of catheter diameter regarding accuracy, precision, and agreement.

Results

The actual average of the catheter diameter was 1.75 ± 0.32 mm (range 1.33 to 2.67 mm). The measurement of catheters by TOD QCA and ISO QCA resulted in mean diameters of 1.78 ± 0.37 mm and 1.88 ± 0.38 mm, respectively. The accuracy/precision of the TOD QCA and the ISO QCA was 0.03 mm/0.21 mm and 0.12 mm/0.20 mm, respectively. The TOD QCA and ISO QCA measures were among the limits of agreement in 96.3 and 94.7% of cases, respectively, and were significantly correlated (rs = 0.93, p < 0.01). However, despite the small difference between the methods (0.10 ± 0.10 mm), the ISO QCA measures were significantly higher than those obtained by the TOD QCA (p < 0.01).

Conclusions

Online QCA with automatic calibration has good accuracy, precision, and correlation, which may represent a promising tool in the catheterization laboratory.