CAD-RADS™ 2.0 - 2022 Coronary Artery Disease - Reporting and Data System An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Cardiology (ACC), the American College of Radiology (ACR) and the North America Society of Cardiovascular Imaging (NASCI)

Abstract

Coronary Artery Disease Reporting and Data System (CAD-RADS) was created to standardize reporting system for patients undergoing coronary CT angiography (CCTA) and to guide possible next steps in patient management. The goal of this updated 2022 CAD-RADS 2.0 is to improve the initial reporting system for CCTA by considering new technical developments in Cardiac CT, including data from recent clinical trials and new clinical guidelines. The updated CAD-RADS classification will follow an established framework of stenosis, plaque burden, and modifiers, which will include assessment of lesion-specific ischemia using CT fractional-flow-reserve (CT-FFR) or myocardial CT perfusion (CTP), when performed. Similar to the method used in the original CAD-RADS version, the determinant for stenosis severity classification will be the most severe coronary artery luminal stenosis on a per-patient basis, ranging from CAD-RADS 0 (zero) for absence of any plaque or stenosis to CAD-RADS 5 indicating the presence of at least one totally occluded coronary artery. Given the increasing data supporting the prognostic relevance of coronary plaque burden, this document will provide various methods to estimate and report total plaque burden. The addition of P1 to P4 descriptors are used to denote increasing categories of plaque burden. The main goal of CAD-RADS, which should always be interpreted together with the impression found in the report, remains to facilitate communication of test results with referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will continue to provide a framework of standardization that may benefit education, research, peer-review, artificial intelligence development, clinical trial design, population health and quality assurance with the ultimate goal of improving patient care. Keywords: Coronary Artery Disease, Coronary CTA, CAD-RADS, Reporting and Data System, Stenosis Severity, Report Standardization Terminology, Plaque Burden, Ischemia Supplemental material is available for this article. This article is published synchronously in Radiology: Cardiothoracic Imaging, Journal of Cardiovascular Computed Tomography, JACC: Cardiovascular Imaging, Journal of the American College of Radiology, and International Journal for Cardiovascular Imaging. © 2022 Society of Cardiovascular Computed Tomography. Published by RSNA with permission.

Keywords: CAD-RADS; Coronary Artery Disease; Coronary CTA; Ischemia; Plaque Burden; Report Standardization Terminology; Reporting and Data System; Stenosis Severity.

Figure 1:

Timeline plots of total quarterly PubMed citations resulting from the search “CAD-RADS” [Title/Abstract] OR “CADRADS” [Title/Abstract]. The date of the search was January 25, 2021. Permission received (63). Radiol Cardiothorac Imaging. 2021 Jun; 3 (3): e210016.

Figure 2:

CAD-RADS 0 – No coronary stenosis. Absence of calcified and non-calcified plaque in the coronary tree. The classification P is not required for CAD-RADS 0.

Figure 3:

CAD-RADS 1/P1 - Minimal coronary stenosis (1–24%). Plaque Burden –P1: Mild amount of plaque burden.

Figure 4:

CAD-RADS 2/P2 – Mild coronary stenosis (25–49%). Plaque Burden – P2: Moderate amount of plaque burden.

Figure 5:

CAD RADS 1/P3 - Plaque Burden – P3: Severe amount of plaque burden – SIS = 7, Extensive amount of diffuse plaque and minimal coronary stenosis.

Figure 6:

CAD-RADS 4B/P4. Plaque Burden – P4: Three vessel severe coronary stenosis with extensive amount of plaque burden – CAC = 3607.

Figure 7:

CAD-RADS 4A/P1. Focal non-calcified plaque in the mid LAD (yellow arrow) with 70–99% severe coronary stenosis and mild amount of focal non-calcified plaque burden (P1) (left). Invasive coronary angiography confirming 70–99% stenosis in the mid LAD (yellow arrow, right). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Figure 8:

CAD-RADS 4B/P2. Three-vessel obstructive disease (>70% stenosis), including in 70–99% stenosis of the proximal RCA (left), 70–99% stenosis of the proximal LAD (middle) and 70–99% stenosis of the mid LCX (right) and moderate amount of non-calcified plaque burden (P2).

Figure 9:

CAD-RADS 4B/P3. Distal left main stenosis with circumferential calcified plaque resulting in >50% stenosis (arrow) and severe amount of plaque (P3 - Calcium Score = 640). Upper left panel: oblique longitudinal plane of the left main coronary artery. Lower left panel – cross-sectional slice of the distal left main coronary artery. Figures on the right - Invasive coronary angiography confirming focal severe stenosis in the distal left main coronary artery.

Figure 10:

CAD-RADS 5/P3. Two examples of 5 mm thick MIPs CCTA cases coded as CAD-RADS 5. Left: Focal, non-calcified occlusion of the proximal RCA (arrow) and severe amount of plaque (P3). Right: Total occlusion of the proximal LCX (arrow) and extensive amount of plaque (P4). A small focus of “orphan” calcium along the distal LCX supports the diagnosis of chronic total occlusion.

Figure 11:

CAD-RADS N/P2. Motion artifacts obscuring the left main, LAD and LCX arteries, which renders these segments non-diagnostic (left) and moderate amount of plaque (P2 - Calcium Score = 247). Motion artifacts in the mid RCA (right) with calcified plaque.

Figure 12:

CAD-RADS 3/P2/N. Motion artifact obscuring the mid RCA (left, arrow), which renders this segment non-diagnostic. There is also stenosis of the mid LAD with 50–69% luminal narrowing (right, arrow), qualifying this lesion as CAD RADS 3 and moderate amount of coronary plaque (P2). Although the mid RCA segment is non-diagnostic, the presence of suspected obstructive disease within the LAD should be coded as CAD RADS 3/P2/N. If the LAD lesion were mild (less than 50% diameter stenosis), and no other stenosis were identified, the patient would be coded as CAD RADS N.

Figure 13:

CAD-RADS 4A/P3/S. In-stent stenosis of the proximal LAD with significant luminal narrowing (70–99% stenosis) and severe amount of coronary plaque (P3). Grading of in-stent stenosis should follow the grading of normal coronary arteries (0% stenosis, 1–24% stenosis, 25–49% stenosis, 50–69% stenosis, 70–99% stenosis, and >99% stenosis). In this case, severe in-stent restenosis designates a CAD-RADS 4A lesion, which would be followed by category P3 for extensive plaque burden and the stent modifier “S” for the presence of stent.

Figure 14:

MODIFIER G. Coronary CTA demonstrating a patent left internal mammary artery to the LAD and patent saphenous vein grafts to the ramus intermedius and second obtuse marginal branch. No stenoses or luminal narrowing throughout the grafts (0% stenosis, left). Invasive coronary angiography demonstrating patent LIMA graft to the LAD (right). When evaluating coronary CTA of patients with bypass grafts, the native coronary artery segments proximal to the graft anastamoses should not be evaluated for purposes of CAD RADS coding. Only the grafts and the native coronary artery segments distal to and including the anastomosis should be evaluated for CAD RADS coding.

Figure 15:

High-risk plaque (HRP) features on coronary CTA. (A) Spotty calcium, defined as punctate calcium within a plaque (B) “napkin ring sign,” defined in a non-calcified plaque cross-sectional image by the presence of two features: a central area of low attenuation plaque that is apparently in contact with the lumen; and a ring-like peripheral rim of higher CT attenuation surrounding this central area (arrows); (C) Positive remodeling, defined as the ratio of outer vessel diameter at the site of plaque divided by the average outer diameter of the proximal and distal vessel greater than 1.1, or Av/[(Ap + Ad)/2] >1.1; and (D) Low attenuation plaque, defined as non-calcified plaque with internal attenuation less than 30 HU. Please note that a combination of two or more high-risk features is necessary to designate the plaque as high-risk for CAD-RADS.

Figure 16:

CAD-RADS 2/P2/HRP. Focal non-calcified plaque in the mid RCA with 25–49% diameter stenosis and overall moderate amount of total coronary plaque. The plaque demonstrates two high risk features, low attenuation (<30 HU) and positive remodeling, thus coding with the modifier “HRP.”

Figure 17:

CAD-RADS 3/P3/HRP/S. Example demonstrating a patent stent (S) in the proximal RCA (0% stenosis) with high-risk plaque (HRP) in the proximal LAD with thick MIP images resulting in 50–69% stenosis and overall severe amount of total coronary plaque burden (P3). In isolation, the proximal LAD lesion would be coded CAD RADS 3/P3/HRP. However, since CAD RADS is coded on a per-patient basis, and a RCA stent is present, this patient would be coded as CAD RADS 3/P3/S/HRP.

Figure 18:

Sample standardized reporting template for Coronary CTA incorporating CAD-RADS coding.