Segmentation of X-ray coronary angiography with an artificial intelligence deep learning model: Impact in operator visual assessment of coronary stenosis severity

BackgroundVisual assessment of the percentage diameter stenosis (%DSVE) of lesions is essential in coronary angiography (CAG) interpretation. We have previously developed an artificial intelligence (AI) model capable of accurate CAG segmentation. We aim to compare operators' %DSVE in angiography versus AI-segmented images. MethodsQuantitative coronary analysis (QCA) %DS (%DSQCA) was previously performed in our published validation dataset. Operators were asked to estimate %DSVE of lesions in angiography versus AI-segmented images in separate sessions and differences were assessed using angiography %DSQCA as reference. ResultsA total of 123 lesions were included. %DSVE was significantly higher in both the angiography (77% & PLUSMN; 20% vs. 56% & PLUSMN; 13%, p < 0.001) and segmentation groups (59% & PLUSMN; 20% vs. 56% & PLUSMN; 13%, p < 0.001), with a much smaller absolute %DS difference in the latter. For lesions with %DSQCA of 50%-70% (60% & PLUSMN; 5%), an even higher discrepancy was found (angiography: 83% & PLUSMN; 13% vs. 60% & PLUSMN; 5%, p < 0.001; segmentation: 63% & PLUSMN; 15% vs. 60% & PLUSMN; 5%, p < 0.001). Similar, less pronounced, findings were observed for %DSQCA < 50% lesions, but not %DSQCA > 70% lesions. Agreement between %DSQCA/%DSVE across %DSQCA strata (<50%, 50%-70%, >70%) was approximately twice in the segmentation group (60.4% vs. 30.1%; p < 0.001). %DSVE inter-operator differences were smaller with segmentation. Conclusion%DSVE was much less discrepant with segmentation versus angiography. Overestimation of %DSQCA < 70% lesions with angiography was especially common. Segmentation may reduce %DSVE overestimation and thus unwarranted revascularization.