In vivo validation of a novel three-dimensional quantitative coronary angiography system (CardiOp-B): comparison with a conventional two-dimensional system (CAAS II) and with special reference to optical coherence tomography.

To validate a novel 3-D QCA system (CardiOp-B) and compare the 2-D (CAAS II) and 3-D systems in in vivo experimental settings. The phantom lumen diameters were also assessed ex vivo by optical coherence tomography (OCT). The accuracy of the 3-D system has not been appreciated.Precision-drilled plexiglass phantoms with 5 different luminal diameters that ranged from 0.5 to 1.9 mm were percutaneously inserted into the coronary arteries in four Yorkshire pigs. Twenty-two angiographic images of the artificial phantom coronary artery stenoses in the pigs were acquired as an in vivo validation test. Quantitative assessments of the minimum and mean lumen diameters were performed using both QCA systems. Ex vivo images of the same phantom lumens were also taken and measured using OCT.Both of the 2-D and 3-D QCA systems significantly underestimated the actual phantom lumen diameters with the exception of measurements taken in the lateral projection at isocenter using the 2-D QCA systems. This underestimation was more significant in the 3-D system (accuracy of 0.19 at isocenter; 0.23 by catheter calibration). There was good agreement between the two QCA systems. OCT measured the ex vivo lumen diameter of plexiglass phantoms precisely.The accuracy of the luminal diameter measurements with the current 2-D system was still superior to the 3-D system. Further development and validation studies under various conditions are warranted. The excellent results achieved by OCT with the ex vivo images indicate its potential as an intravascular quantitative imaging tool for future clinical practice.