Table 1

CT-FFR techniques

Technique	Computation flow dynamic method (CFD)	Computational time	Processing	Cost
cFFR (Siemens)	Reduced-order algorithm and machine-learning algorithm based on synthetic lesions	20 min	Local workstation	License
FFR_CT (HeartFlow)	Reduced-order algorithm and machine-learning algorithm for coronary segmentation	1–4 hours	Cloud based	£530/patient
CT-FFR (Toshiba)	Reduced-order one-dimensional fluid model	27 min	Local workstation	License
CT-FFR	Lumped parameter model using a vessel length–based CFD approach	30 min	Local workstation	n/a
Virtual Functional Assessment Index (vFAI)	CFD to derive ratio of distal to proximal pressure	25 min	Local workstation	n/a

There are a range of computation fluid dynamic methods that are used to derive CT-FFR from CT coronary angiography. There are varying complexities and computational processing depending on the technique.
CFD, computation fluid dynamics; CT-FFR, CT-derived fractional flow reserve; n/a, not available.