ARRS Case of the Week: July 31, 2017

CARDIOVASCULAR IMAGING: Coronary Arteries

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

History

28-year-old woman with chest pain and no known cardiovascular risk factors who reports having a nonspecific rash and fever in childhood.

Imaging Findings

Double oblique maximum-intensity-projection CT images of the right coronary artery (A) and the left main trunk and its bifurcation, including the proximal and mid left anterior descending and proximal circumflex arteries (B) and 3D volume-rendered CT image of the coronary tree (C) show focal areas of increased caliber of the coronary arteries.

Atherosclerotic coronary artery aneurysm
Atherosclerotic plaque with positive remodelling
Congenital coronary artery aneurysm
Coronary artery aneurysm associated with a connective tissue or inflammatory disorder
Coronary artery ectasia
Kawasaki disease with coronary artery aneurysm

Diagnosis

Kawasaki disease with coronary artery aneurysm

Teaching Points

The prevalence of coronary artery aneurysms varies from 0.3% to 5%. A coronary artery aneurysm is defined as any segment with a cross-sectional diameter exceeding 1.5 times that of the normal adjacent segment and involving less than 50% of the total length of the vessel. It can be saccular or fusiform. Coronary artery ectasia differs from aneurysm in that the coronary artery dilatation involves more than 50% of the length. According to the criteria of the Japanese Ministry of Health, a coronary artery aneurysm is present when the diameter of the lumen is more than 3 mm in children younger than 5 years and more than 4 mm in those 5 years old and older. Geographic location and age group are important factors in the differential diagnosis of coronary artery aneurysm. The most common cause of aneurysms in Western countries is atherosclerosis, but in Japan it is Kawasaki disease. In children and young adults, the cause of aneurysm and ectasia is usually Kawasaki disease or congenital or compensatory dilatation in the form of ectasia associated with fistulas or anomalous origin of the coronary artery from the pulmonary artery (ACAPA). To diagnose inflammatory, connective tissue, posttraumatic, and infectious (mycotic) aneurysms, knowing the clinical history and presentation is essential. Like atherosclerosis, such entities are more likely to cause aneurysms than to cause ectasia. Kawasaki disease (mucocutaneous lymph node syndrome) is acute self-limited multisystemic panarteritis that involves the coronary arteries, leading to aneurysms or ectasia in 15–25% of patients, one half of whom have complete resolution within a 2-year follow-up period. Administration of gamma-globulin and aspirin reduces the rate of occurrence of coronary artery aneurysm. Coronary CT angiography is the noninvasive modality of choice in the diagnosis of coronary artery aneurysms and ectasia. It allows accurate description of location, size, wall thickening, residual lumen, and the presence of associated findings, such as thrombus and dissection.

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