Segment involvement score

Last revised by Joachim Feger on 19 Oct 2022

The segment involvement score (SIS) represents an estimate of the extent of the overall coronary plaque burden 1-3.

The segment involvement score is determined on coronary CTA by designation of a score of 1 for each one of the coronary artery segments with a detectable atherosclerotic coronary plaque, irrespective of the plaque size or individual plaque burden in that particular segment 1-3.

The segment involvement score can be used as an estimate for coronary artery calcification and  categorize or grade the overall amount of coronary plaque burden the CAD-RADS 2.0 system 3:

  • SIS ≤2              P1 (mild)

  • SIS 3-4             P2 (moderate)

  • SIS 5-7             P3 (severe)

  • SIS ≥8              P4 (extensive)

A higher segment involvement score has been associated with higher probability and is considered an independent predictor of cardiovascular events 4,5.

The segment involvement score has been first described by the American radiologist James K. Min and colleagues in 2007 1.

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