Reply to: assessment of pericoronary adipose tissue attenuation

We read with interest the remarks of Tan et al.1 on our systematic review and meta-analysis on the prognostic role of pericoronary fat attenuation index (FAI).2 We fully agree with the comments raised by the authors and several points need to be highlighted. The field is moving fast, with various methodological variations on FAI measurements being reported, e.g. proximal coronary artery segments analysis vs. coronary lesion-specific analyses, non-adjusted FAI values for tube voltage, the radial distance from the arterial wall used for the segmentation of perivascular tissue and various other anatomical parameters. The diagnostic or prognostic value of FAI from such methodological variations is not the same. For example, it has been previously shown that adjusted FAI values have superior prognostic value to the unadjusted mean attenuation values of pericoronary fat.3 In our meta-analysis,2 these issues on the methodological variations between studies are fully acknowledged, and a random-effects meta-analysis was used to account for such differences between studies.