Absolute metabolite concentrations from poorly spatially-resolved MR response signals

摘要

An improved method of assaying local metabolite concentrations the chemical entity (CE) of interest, of a living subject by non-invasive means using magnetic resonance (MR) spectroscopy employs acquiring an MR response signal for a naturally occurring, abundant marker material of known concentration, such as water (H.sub.2 O) from the subject. An MR response signal is also acquired from the CE being assayed, e.g., adenosine triphosphate (ATP) with phosphorus (.sup.31 P) nuclei producing the MR response signal. The subject is replaced with a test phantom having a known concentration of the marker material and a reference concentration standard (e.g., phosphate) having the same resonant nuclei as the CE. Both sets of MR response signals are again acquired. The volume of tissue contributing to the CE MR response signal in the subject is deduced from the ratios of marker material MR response signals from the subject and phantom and the known concentration of the test phantom. The concentration of CE in the subject is determined from the volume and the measurements of the test phantom. The method avoids problems of tissue volume determination from images. The technique may be applied to non-invasive evaluation of cardiac tissue damage by assaying phosphate concentration of volume elements of the subject's heart.