ARRS Case of the Week- Aug 28, 2017

CARDIOVASCULAR IMAGING: Coronary Arteries

Case Author: Eric Kimura-Hayama, MD, Instituto Nacional de Cardiologia Ignacio Chavez

History

55-year-old man with hypertension and dyslipidemia who reports having dyspnea.

Imaging Findings

Curved planar reformatted CT image of the right coronary artery (A) and corresponding short-axis images (B) obtained at the level between the white lines in A show a filling defect of mixed attenuation in the coronary artery.

Artifact causing pseudostenosis
Mild stenosis by atherosclerotic plaque
Moderate stenosis by atherosclerotic plaque
Severe stenosis by atherosclerotic plaque

Diagnosis

Severe stenosis by atherosclerotic plaque

Teaching Points

Coronary CT angiography (CTA) is a reliable noninvasive method of evaluation of suspected coronary artery disease. It is mainly used in the care of patients at intermediate risk and has a high negative predictive value (95–99%). CT depicts the lumen and wall of the coronary arteries, unlike invasive angiography, which depicts only the lumen. Plaques are classified as noncalcified, calcified, and mixed. Degree of stenosis is evaluated quantitatively and qualitatively and is classified according to degree of luminal narrowing as follows: normal, or absence of plaque; minimal, or less than 25%; mild, or 25–49%; moderate, or 50–09%; severe, or 70–99%; and total occlusion. The accuracy of CTA largely relies on preprocedure risk stratification and type of plaque. In general, the degree of stenosis and calcified plaques are overestimated with CTA. In such cases, a stress myocardial perfusion examination is recommended.

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