QUALITY ASSESSMENT IN IN-VIVO NMR-SPECTROSCOPY .1. INTRODUCTION, OBJECTIVES, AND ACTIVITIES

By enabling noninvasive measurements of tissue biochemistry, nuclear m agnetic resonance spectroscopy (MRS) provides a unique means of charac terizing tissues. Differences in equipment, techniques, and methodolog y between different laboratories cause major difficulties when compari ng results, whether from measurements of tissue metabolism, or from th e effects of different therapies. This is of concern in critically eva luating work from different laboratories and centres, causing potentia l difficulties in reproducing results, limiting the establishment of M RS as a standard method of diagnosis and of characterising disease and response to therapy in the laboratory and clinic. It also poses parti cular problems in establishing the multicentre clinical trials of MRS that are now required to provide adequate statistical power in confirm ing the encouraging preliminary clinical observations. These difficult ies arise principally from imperfect localization of signal from selec ted regions of interest in the body, and from the subsequent analyses of the MRS spectra. Improvement is possible by establishing agreed pro cedures for test measurements and for data analysis, and by using appr opriate test objects and test substances to establish the quality of m easurements. A concerted research project on characterisation of biolo gical tissues by NMR, principally concerned with MR imaging (MRI), was activated in 1984 by the European Economic Community as part of its t hird Medical and Health Research Programme, under the auspices of the Biomedical Engineering Concerted Actions' Committee (COMAC-BME). In 19 88, this project was prolonged for 5 years, when the programme was exp anded to encompass MRS. A series of five accompanying papers describes (a) the test protocols and objects agreed for assessing the quality o f volume selective MRS measurements; (b) the experimental trials perfo rmed for a multicentre evaluation of these procedures on experimental and clinical systems; and (c) the results of a joint quantitative data analysis study on in vivo NMR time-domain test signals.