Myocardial first-pass perfusion cardiovascular magnetic resonance: history, theory, and current state of the art

In less than two decades, first-pass perfusion cardiovascular magnetic resonance (CMR) has undergone a wide range of changes with the development and availability of improved hardware, software, and contrast agents, in concert with a better understanding of the mechanisms of contrast enhancement. The following review provides a perspective of the historical development of first-pass CMR, the developments in pulse sequence design and contrast agents, the relevant animal models used in early preclinical studies, the mechanism of artifacts, the differences between 1.5T and 3T scanning, and the relevant clinical applications and protocols. This comprehensive overview includes a summary of the past clinical performance of first-pass perfusion CMR and current clinical applications using state-of-the-art methodologies

Integrated MRI studies of cardiac function and perfusion

The heart pumps blood to deliver oxygen and other metabolites to and remove waste products from the body, including the heart itself. The heart is a very efficient organ with nearly maximal oxygen extraction from the blood in the resting state. Within seconds of the loss of blood supply, as seen with coronary occlusion, a diminution in heart pump function occurs. Within minutes of coronary occlusion, permanent injury or myocardial infarction ensues. Thus, due to this close coupling of the heart\u27s ability to contract and it\u27s blood supply, myocardial infarction and ischemia are major causes of morbidity and mortality in the Western World. Many conventional imaging modalities have been developed to look at either the heart\u27s contractile function or perfusion. No currently available clinical technique is well-suited to examine myocardial function and perfusion simultaneously. Thus, the primary focus of the dissertation was to develop an integrated magnetic resonance imaging (MRI) exam to non-invasively obtain data which could be used to describe both myocardial contraction and blood flow. In this study, MRI with tissue tagging was performed to assess regional left ventricular mechanical function in normal dogs and dogs with experimentally-induced myocardial infarctions. New MRI techniques were developed to simultaneously evaluate regional myocardial blood flow using gadolinium-chelate contrast agents. Using a 3D finite element model, regional dysfunction in the infarcted and adjacent non-infarcted zone was quantified. A multicompartment model of the heart was developed to semi-quantitatively assess regional perfusion based on the contrast-enhanced MR images. The ability to define the extent and severity of the infarction was improved using this integrated MR exam. Thus, MRI shows promise as a noninvasive tool to unravel the complex interaction between cardiac function and perfusion. Future research will explore the use of this integrated MRI exam to aid in the distinction of hibernating, stunned, and nonviable myocardium

Integrated MRI studies of cardiac function and perfusion

The heart pumps blood to deliver oxygen and other metabolites to and remove waste products from the body, including the heart itself. The heart is a very efficient organ with nearly maximal oxygen extraction from the blood in the resting state. Within seconds of the loss of blood supply, as seen with coronary occlusion, a diminution in heart pump function occurs. Within minutes of coronary occlusion, permanent injury or myocardial infarction ensues. Thus, due to this close coupling of the heart\u27s ability to contract and it\u27s blood supply, myocardial infarction and ischemia are major causes of morbidity and mortality in the Western World. Many conventional imaging modalities have been developed to look at either the heart\u27s contractile function or perfusion. No currently available clinical technique is well-suited to examine myocardial function and perfusion simultaneously. Thus, the primary focus of the dissertation was to develop an integrated magnetic resonance imaging (MRI) exam to non-invasively obtain data which could be used to describe both myocardial contraction and blood flow. In this study, MRI with tissue tagging was performed to assess regional left ventricular mechanical function in normal dogs and dogs with experimentally-induced myocardial infarctions. New MRI techniques were developed to simultaneously evaluate regional myocardial blood flow using gadolinium-chelate contrast agents. Using a 3D finite element model, regional dysfunction in the infarcted and adjacent non-infarcted zone was quantified. A multicompartment model of the heart was developed to semi-quantitatively assess regional perfusion based on the contrast-enhanced MR images. The ability to define the extent and severity of the infarction was improved using this integrated MR exam. Thus, MRI shows promise as a noninvasive tool to unravel the complex interaction between cardiac function and perfusion. Future research will explore the use of this integrated MRI exam to aid in the distinction of hibernating, stunned, and nonviable myocardium