[Clinical magnetic resonance spectroscopy: feasibility and methods using whole body tomographs]

Abstract

MR Spectroscopy offers the unique possibility of monitoring the metabolism of various organs non-invasively. Using examples of 1H and 31P MR spectra, experimental and commercially available techniques are presented and evaluated with regard to their potential clinical application. An example of a 1H human brain spectrum with a pathological lactate level illustrates the requirements for MRS examinations in terms of spatial and spectral resolution. STEAM, Spin-Echo, and Chemical Shift Resolved Imaging (CSI) techniques for 1H MRS are compared. In the field of 31P MRS, typical CSI spectra of the brain and liver are presented. First experimental results with a new double-oblique 3D-CSI technique for measurement of PCr/ATP ratios of different anatomical regions of the human heart are shown. The advantages of using double-resonance techniques for Nuclear Overhauser Enhancement (NOE) and decoupling are shown by the example of the phosphodiesters of the liver. The energy metabolism of skeletal muscle under exercise is resolved with 5 sec/spectrum, showing breakdown and synthesis of photocreatine (PCr) and inorganic phosphate (Pi). Appropriate instrumentation and technique are available to many clinics today; great interest now is directed towards the diagnostic value of MRS for certain indications.