Extending the Frontiers of Cardiac Magnetic Resonance

Abstract

Inflammation is a common reaction in biological systems, which develops, for example, to defend the body against infectious agents, to repair tissue, and to respond to ischemic insults. It can also be a disease process in itself, as in autoimmune diseases. Flogel et al1 describe a novel, elegant, and noninvasive approach to inflammatory mechanisms at a cellular level. The noninvasive nature of their strategy is of paramount importance. In particular, it allows for a series of repetitive measurements to be obtained from the same animal and thus yields information on the evolution of the inflammatory process without destruction of the system under investigation. This is almost impossible to achieve with invasive techniques. Article p 140 Flogel et al elegantly exploit a primary mode of action of inflammatory cells (ie, phagocytosis of potentially harmful agents), which in this case happens to be a magnetic resonance (MR)–active contrast medium. Another remarkable aspect of their work is the use of the naturally occurring stable fluorine isotope 19F as the MR-active nucleus for imaging. Why is this unique? This 19F-MR imaging strategy takes advantage of the fact that after administration of 19F-containing compounds, any signal detected in the body via MR imaging (MRI) is emanating from the injected contrast medium (ie, an extraordinary contrast-to-noise ratio [CNR] is present, because no background signal from the body is detected by 19F-MR imaging). If the MR scanner is thereafter tuned to the 1H resonance frequency, conventional MRI occurs, and all morphological and functional information on the organ can be acquired. Because this imaging is performed in the same location and with the same equipment, registration is ideal; this allows “fusion imaging” to be used to combine specific signals of inflammatory cells (19F imaging) with organ function and anatomy (conventional 1 …