Black-Blood CMR

Abstract

Cardiac magnetic resonance is often used to provide detailed information on structures such as the myocardium, pericardium, pulmonary veins, and emanating great vessels. While blood travels throughout the heart and blood vessels, its signal may obscure the assessment of these structures depending on the clinical questions being addressed. Black blood imaging techniques seek to suppress the signal from blood and thereby improve delineation of cardiovascular anatomy. Fast spin echo-based sequences are in routine use for the suppression of blood flowing into the imaging plane. Such approaches have known limitations that may result in inadequate image quality or artifacts in the image. More recent advances have overcome some of these limitations, but it is incumbent upon the reader to recognize them as they occur. For instance, cardiac motion may lead to signal loss, and may be overcome by optimizing the cardiac phase during which data acquisition occurs. For those relying on black blood imaging to detect myocardial edema, caution must be exerted in recognizing spuriously bright areas of myocardium resulting from slow-flowing blood. While contemporary tissue mapping techniques overcome some of these limitations, black blood imaging will remain an important tool in the CMR armamentarium, particularly with increasing prevalence of implantable devices in patients with various forms of cardiovascular disease. Particularly with bright blood imaging, devices such as intravascular stents and implantable loop recorders can produce considerable susceptibility artifact obscuring visualization of the anatomy of interest; using black blood imaging can significantly reduce this artifact.