TISSUTAL IMAGING BY NUCLEAR-MAGNETIC-RESONANCE

The present work reviews the main applications of nuclear magnetic res onance (NMR)-technology and, in particular, of magnetic resonance imag ing (MRI) to tissutal analysis. To date, MRI represents a precise and reliable tool to investigate morphology and functional modification of tissues in vivo, providing information consistent with histology. MRI has numerous advantages over conventional techniques: it is harmless to tissues; volume measurements in vivo could be useful for morphometr ic studies; the same tissue can be examined several times (e.g. at dif ferent ages); several organs can be examined at the same time; serial sections of relevant structures can be obtained in all planes, thereby allowing detailed reconstruction of the three-dimensional configurati on of organs; motion within a tissue can be detected; and subsequent h istological and ultrastructural studies of the tissue are possible. Th e main drawback (besides the cost of the basic instrumentation) is tha t resolution is relatively low in comparison with light microscopy. Fi nally, the analysis of the results is difficult, needing interdiscipli nary competence, and MRI methods of tissutal analysis are not yet well standardized. Therefore, in our opinion, MRI is an interesting tool, complementary to other histological techniques, and it cannot be ignor ed by microscopists. However, in vivo MRI data must be evaluated with caution and histological controls are always required.