<International Circulation>: Both IVUS and FFR are valuable in evaluating and guiding PCI and DES implantation， so how do you comment the role and significance of each one of the 2 modalities? More and more researches have shown great evaluating and prognostic value of FFR， can FFR totally replace IVUS in the future?

Dr. Waksman: These are two separate tests. The IVUS assesses more anatomical features and the FFR assesses the physiological status. Sometimes， they are complimentary， with FFR telling us if the lesion is significant， while IVUS tells us about the morphology of the lesion and it also assesses some technical issues such as whether we must pre-dilate， post-dilate， etc. What we are trying to find out is if we can correlate the relationship between the anatomical luminology to the physiology and find out if we can do it with a one-stop shop approach. So， if you do IVUS for other reasons， can you also translate the lumen area to a physiological correlation? In essence， these are two complimentary technologies， with one helping us more to decide if we should intervene and the other one is used to optimize the intervention.

<International Circulation>: