Abstract: Noninvasive, MR-compatible methods and systems optically detect mechanical cardiac activity by anatomic (e.g., esophageal) movements. Most preferably, esophageal motion is detected optically and is indicative rhythmic cardiac activities. This esophageal motion may then be detected and used to provide a signal indicative of periods of cardiac activity and inactivity. The signal may be further processed so as to generate a trigger signal that may be input to a MR scanner. In such a manner, MR microscopy may be accomplished to acquire information at a specific phase of the cardiac cycle, for example, in synchrony with periods of cardiac inactivity. Moreover, since mechanical cardiac activity is detected and employed, instead of electrical activity as is employed in conventional techniques, the present invention is immune to electromagnetic interference during MR microscopy. As a result, robust cardiac signals may be monitored and gated during 2-dimensional and 3-dimensional in vivo microscopy.

Abstract: Noninvasive, MR-compatible methods and systems optically detect mechanical cardiac activity by anatomic (e.g., esophageal) movements. Most preferably, esophageal motion is detected optically and is indicative rhythmic cardiac activities. This esophageal motion may then be detected and used to provide a signal indicative of periods of cardiac activity and inactivity. The signal may be further processed so as to generate a trigger signal that may be input to a MR scanner. In such a manner, MR microscopy may be accomplished to acquire information at a specific phase of the cardiac cycle, for example, in synchrony with periods of cardiac inactivity. Moreover, since mechanical cardiac activity is detected and employed, instead of electrical activity as is employed in conventional techniques, the present invention is immune to electromagnetic interference during MR microscopy. As a result, robust cardiac signals may be monitored and gated during 2-dimensional and 3-dimensional in vivo microscopy.

Abstract: Whole body animal specimens (preferably small mammals, such as laboratory rats, mice and the like) may be prepared for enhanced MR microscopy. Preferably, whole body animal specimens may be prepared for magnetic resonance (MR) microscopy by perfusing a mixture of a fixative and a MR contrast agent intravascularly of the animal specimen. The MR contrast agent is preferably a gadolinium compound, while the fixative is preferably formalin. In especially preferred embodiments, methods are provided whereby whole body animal specimens may be prepared for magnetic resonance (MR) microscopy by perfusing a MR contrast agent intravascularly of the animal specimen sequentially (a) into a jugular vein and out a carotid artery of the specimen, (b) into a carotid artery and out a jugular vein of the specimen, (c) into a carotid artery and out a femoral artery of the specimen; and then (d) into a jugular vein and out a femoral vein of the specimens.