David F. Cuevas Cueto, MD · Updated September 27, 2026 · Sources: SCCT 2026 and CAD-RADS 2.0
The 2026 SCCT expert consensus document updates the 2014 SCCT guidelines for the interpretation and reporting of coronary CT angiography. This page compares eight changes, each with a verbatim quote from both documents; 2026 page numbers refer to the journal pre-proof PDF and may change in the final version. The glossary definitions already follow the 2026 document.
Overall plaque burden (P1–P4)#
SCCT 2014
The guideline asked for the extent of disease to be described but had no overall plaque burden scale. The only global index was the calcium score (total Agatston score and percentile), reported when a noncontrast scan was acquired.
SCCT 2014, section 4 (Noncontrast coronary interpretation: coronary calcium scoring), p. 345; Table 4, p. 347 · «at the minimum, the total calcium score should be reported as well as the percentile as compared with age and gender nomograms.»
SCCT 2026
Overall plaque burden is a report element with a Strong recommendation. It is graded visually as mild, moderate, severe, or extensive (P1–P4) in combination with the calcium score or the SIS (Table 3). Quantitative plaque volume is optional (Weak, 1.3).
SCCT 2026, Table 5, p. 51; Table 3, p. 49; section "c. Plaque volume", p. 14; Table 6, p. 52 · «Plaque burden assessment is performed qualitatively as mild, moderate, severe, or extensive in combination with either the calcium score or the segmental involvement score.»
In practice. Every report with plaque includes an overall burden line alongside the stenosis category, e.g., “moderate plaque burden (P2; SIS 4).” Without a calcium scan, burden is estimated with the SIS or visually.
Glossary term: Plaque burden (P1–P4)
Impression and recommendations using CAD-RADS 2.0#
SCCT 2014
The impression summarized clinically important findings as clearly and in as standardized a fashion as possible, but without a category system, since CAD-RADS did not yet exist. Clinical recommendations were optional (Table 4).
SCCT 2014, section 10.7 (Impressions), p. 352; Table 4 ("Clinical recommendations: Optional"), p. 347 · «All clinically important findings should be summarized in this section in as clear and standardized fashion as possible.»
SCCT 2026
The coronary impression should be succinct and in CAD-RADS 2.0 style (Strong, Table 6). According to the text, the stenosis category can be given, followed by plaque burden (P1–P4) and then the modifiers. Management recommendations per CAD-RADS 2.0 are graded Moderate (2.4).
SCCT 2026, section "f. Impression", pp. 35–36; Table 6 (Impression/Conclusion and Recommendation), p. 52 · «A CAD-RADS category of stenosis (0,1,2,3,4A,4B,5,N) followed by plaque volume (P1,P2,P3,P4) and then modifiers (N,HRP,I,S,G,E) can be given following CAD-RADS 2.0 system»
In practice. The impression summarizes the coronary findings with the CAD-RADS 2.0 string, e.g., “CAD-RADS 3/P2/HRP.” Recommendations, optional in 2014, follow CAD-RADS 2.0 and are worded as suggestions for the referring physician to weigh in the clinical context.
Glossary term: CAD-RADS coding order and modifiers
Stenosis grading in dense calcified plaque#
SCCT 2014
The guideline only warned that blooming artifact makes calcified plaque and stents appear to narrow the lumen more than they actually do. It gave no instruction on how to grade or word the stenosis.
SCCT 2014, section 5.1.2 (Metal density artifacts), p. 346 · «blooming artifacts commonly make calcified plaque and stents appear to narrow the lumen more than they actually do.»
SCCT 2026
In dense calcified plaque, the highest visualized stenosis grade is reported with a caveat of possible overestimation from calcium blooming (Strong, 2.6). The text mentions two alternatives: subtracting 10–20% or deeming the segment non-interpretable.
SCCT 2026, Table 5, p. 51; section "e. Dense calcified plaques", p. 16 · «In a dense calcified plaque, the highest visualized grade of stenosis is interpreted with the expression of potential overestimation from calcium blooming.»
In practice. Over dense calcium, report the visualized grade with the caveat rather than silently subtracting a percentage, e.g., “severe stenosis (70–99%), possibly overestimated due to calcium blooming.”
Glossary term: Blooming artifact
Minimum vessel diameter assessed#
SCCT 2014
No minimum assessable diameter was set; readers were only asked to state which artery or segment was not interpretable and why. The only 1.5-mm threshold appeared in the definition of D1.
SCCT 2014, section 5.5, p. 348; Appendix 1, p. 358 · «In addition, the reader should specifically state if an artery or artery segment is not interpretable and why.»
SCCT 2026
In good-quality scans, all branches ≥1.5 mm are assessed (Strong, Table 5); in standard-quality scans, those ≥2.0 mm. Any non-interpretable segment ≥1.5 mm is named with its cause, and well-seen plaque in small vessels is reported, noting the small caliber.
SCCT 2026, section "d. Qualitative grading of stenosis", p. 15; Table 5, p. 51 · «With a good-quality scan, all branches with diameter ≥ 1.5 mm and with a standard quality scan, all branches with diameter ≥ 2.0 mm should be included in the interpretation»
In practice. Branches <1.5 mm are not graded and do not justify an N; well-seen plaque in them is described, noting the small caliber. In standard-quality scans, the threshold rises to 2.0 mm.
Glossary term: Minimum assessable vessel diameter
Disease at segment junctions and bifurcations#
SCCT 2014
There was no rule for assigning a lesion at the boundary between two segments; the guideline only recommended a standardized segmentation model.
SCCT 2014, section 5.3 (Coronary segmentation), p. 346 · «A standardized approach to coronary segmentation improves description and communication of findings.»
SCCT 2026
Disease at the intersection of segments, including bifurcations, is assigned to the preceding (more proximal) segment.
SCCT 2026, section "a. Coronary artery anatomy", p. 11 · «Disease at the intersection of segments (including bifurcations) is assigned to the preceding coronary segment.»
In practice. A focal plaque at the junction of the proximal and mid LAD is recorded as proximal LAD, not in both segments, so it is named with a single segment and counted once in the SIS.
Glossary term: Assignment of disease at segment intersections and bifurcations
Proximal LAD boundary and definition of D1 and D2#
SCCT 2014
The proximal LAD ended at the first large septal branch or D1, whichever was more proximal. D1 was simply the first diagonal branch (>1.5 mm).
SCCT 2014, Appendix 1 (Axial coronary anatomy legend), segments 6 and 9, p. 358 · «End of LM to the first large septal or D1 (first diagonal; >1.5 mm in size) whichever is most proximal»
SCCT 2026
The proximal LAD ends only at the first large septal branch. D1 and D2 are the first and second of the two largest diagonal branches traversing the anterolateral left ventricular wall.
SCCT 2026, Table 1 (segments 6, 9 and 10), p. 47 of the pre-proof · «End of LM to the first large septal branch … First of the largest two diagonal branches traversing the anterolateral left ventricular wall»
In practice. A diagonal arising before the first large septal branch no longer marks the end of the proximal LAD. A small, early diagonal is not labeled D1; that label belongs to the first of the two largest diagonals.
Glossary term: Proximal, mid and distal left anterior descending artery
Plaque type: partially calcified and ≥75% predominance#
SCCT 2014
Plaque type was reported per segment as calcified, predominantly calcified, noncalcified, predominantly noncalcified, or “partially noncalcified,” with no threshold for predominance. “Noncalcified” was already preferred over “soft” or “lipid-rich.”
SCCT 2014, section 10.6.2, p. 352; section 5.4, p. 346 · «Plaque type should be described as calcified, predominant calcified, noncalcified, predominant noncalcified, or partially noncalcified.»
SCCT 2026
Plaque type is recorded per segment in three classes: calcified, partially calcified, and noncalcified (Strong, Table 6). A partially calcified plaque may be specified as predominantly calcified or predominantly noncalcified when that component is ≥75%. “Noncalcified” or “low attenuation” is recommended over “soft” or “lipid-rich.”
SCCT 2026, section "b. Atherosclerotic plaque", p. 13; Table 6, p. 52 · «A partially calcified plaque can be specified as predominantly calcified with ≥ 75 % of the plaque component calcified»
In practice. Write “partially calcified plaque” rather than “partially noncalcified,” and reserve “predominantly” for a component ≥75%. Avoiding “soft” is not new; the 2014 guideline already discouraged it.
Glossary term: Partially calcified plaque
Circumflex: proximal and distal segments only#
SCCT 2014
Segment 13 was named “mid and distal LCx” and ran in the AV groove, distal to OM1, to the end of the vessel or the origin of the left PDA.
SCCT 2014, Appendix 1, segment 13, p. 358 · «Mid and distal LCx … Traveling in the atrioventricular groove, distal to the OM1 branch to the end of the vessel or origin of the L-PDA (left PDA)»
SCCT 2026
The LCx is divided only into proximal and distal segments. Segment 13 is the distal LCx, the remainder of the artery in the AV groove beyond OM1. There is no mid LCx segment.
SCCT 2026, section "a. Coronary artery anatomy", p. 11; Table 1, segment 13, p. 47 · «the left circumflex coronary (LCx) artery is divided into proximal and distal segments»
In practice. A lesion beyond OM1 is reported as “distal LCx,” not “mid” or “mid-distal LCx.” The boundary between the two segments remains the origin of OM1.
Glossary term: Proximal and distal left circumflex artery