Stress Cardiovascular Magnetic Resonance Imaging for the Detection of Coronary Artery Disease

Abstract

Stress cardiovascular magnetic resonance (CMR) imaging has received extensive validation for the assessment of ischemic heart disease. Without ionizing radiation exposure, it offers in-depth information regarding cardiac structure and function, presence and degree of myocardial ischemia and myocardial viability. When compared to other imaging modalities, it has demonstrated excellent sensitivity and specificity in detecting functionally relevant coronary artery stenosis, as well as strong prognostic value in clinical risk stratification. The current scientific data support a greater expansion of stress CMR. This review investigates the current stress CMR techniques and protocols, as well as its relevance in diagnosis and prognosis of coronary artery disease.

Keywords: cardiovascular magnetic resonance imaging; coronary artery disease; myocardial ischemia; myocardial perfusion.

Fig. 1.

Example of abnormal stress CMR. The first-pass perfusion images are usually acquired in three short axis slices, at the basal (A), mid (B) and apical (C) ventricular level during coronary maximal vasodilation. This example shows an inducible perfusion defect, appearing as a hypointense subendocardial area (indicated by the yellow arrow lines) in the inferior and infero-septal segments. CMR, cardiovascular magnetic resonance.

Fig. 2.

Example of stress CMR protocol with adenosine. The suggested protocol lasts about 30 min and starts with the acquisition of scout images to localize the heart (3 min). Standard long axis cine images are then acquired in 4-chamber, 2-chamber and 3-chamber orientation (6 min). First-pass perfusion images are therefore acquired in three short axis slices, during hyperemic conditions obtained with the administration of a vasoactive agent (i.e., adenosine), to assess for perfusion defects (10 min). Dosage of adenosine and contrast agent infusion are reported. In the following minutes, short axis cine images covering the entire ventricle are performed (20 min). At least 10 min after stress perfusion, rest perfusion images are acquired (23 min). About 5 min after the 2nd GBCA bolus injection, LGE images are performed, investigating the presence of myocardial scars (30 min). CMR, cardiovascular magnetic resonance; GBCA, gadolinium-based contrast agents; LGE, late gadolinium enhancement.

Fig. 3.

Example of stress CMR images showing the ‘dark-rim artifact’. CMR adenosine-stress perfusion in a 44-year-old man with a known congenital coronary artery abnormality (RCA with a high take off and inter-arterial course). Short axis rest and stress perfusion images are shown respectively at the basal (A,D), mid-ventricular (B,E), and apical (C,F) levels. There is evidence of a transient hypointense area in the subendocardial layer of the mid-ventricular septal segments (yellow arrows) both in the rest and stress images (B,E), during the early phase of passage of GBCA bolus through the left ventricle, suggestive for “dark rim artifact”. Corresponding LGE images (G,H,I) show no myocardial scars. CMR, cardiovascular magnetic resonance; LGE, late gadolinium enhancement; RCA, right coronary artery; GBCA, gadolinium-based contrast agent.

Fig. 4.

Example of positive CMR adenosine-stress perfusion. We present the case of a 73-year-old man with new onset of ventricular arrythmia on exercise test and a history of previous ACS and RCA angioplasty. Short axis rest and stress perfusion images are shown respectively at the basal (A,D), mid-ventricular (B,E), and apical (C,F) level. The stress images show the presence of a perfusion defect, appearing as subendocardial hypointense area in the inferior septum, inferior wall and in the mid portion of the anterior and antero-septal walls (yellow arrow heads). Corresponding LGE images (G,H,I) show no myocardial scarring. The patient underwent a coronary angiography which revealed diffuse CAD with severe stenosis at the proximal tract of the LAD artery (yellow arrow line, J). and at the origin of the intermediate and the first diagonal branches (yellow arrow line, K). Moreover, there was an intrastent occlusion in the RCA with a collateral circulation (yellow arrow line, L). CMR, cardiovascular magnetic resonance; ACS, acute coronary syndrome; CAD, coronary artery disease; LAD, left anterior descending; LGE, late gadolinium enhancement; RCA, right coronary artery.

Fig. 5.

Example of CMR adenosine-stress perfusion in the presence of ischemic scar. This is the case of a 68-year-old man with a history of subacute myocardial infarction and previous unsuccessful percutaneous angioplasty on the RCA. Short axis rest and stress perfusion images are shown respectively at the basal (A,D), mid-ventricular (B,E), and apical (C,F) level. There is evidence of hypoperfusion, appearing as a hypointense subendocardial area in the inferior septum, inferior wall and in the mid portion of the anterior wall (yellow arrow heads). Corresponding LGE images (G,H,I) show ischemic scars (yellow arrow lines) with a transmural distribution in the inferior septum and inferior wall. Moreover, there is subendocardial LGE with a 50–75% transmurality in the anterior wall. The perfusion defects appear both in the rest and stress images and are related to the presence of non-viable myocardium (scar transmurality $>$50%), as shown in the LGE images. The patient was deferred from coronary revascularization. CMR, cardiovascular magnetic resonance; LGE, late gadolinium enhancement; RCA, right coronary artery.

Fig. 6.

How to start a stress CMR service. This image shows all the practical steps necessary to implement a stress CMR service in the clinical practice and optimize the workflow. CMR, cardiovascular magnetic resonance; BP, blood pressure; ECG, electrocardiogram; Gad, gadolinium.