Fig. 1

The non-coronary cusp-parallel technique to predict optimal projection during transcatheter aortic valve implantation. a After identifying the native annulus, the S-curve of the annulus would be generated by FluoroCT software, on which the annulus would always be aligned. Then one plane parallel to the annulus where all commissures could be clearly observed would be chosen to determine the non-coronary cusp (NCC) -parallel view. The S-curve is tracked until the red line (sagittal plane) connects the R-N commissure and L-N commissure on the determined transverse plane, showing the NCC-parallel view as right anterior oblique (RAO) 25 and caudal (CAU) 23. b As for type 0 bicuspid aortic valve patients, commissures between the two cusps would be connected by the red line when tracking the annulus S-curve, showing the NCC-parallel view as RAO 29 and CAU 32