Techniques and approaches to proton NMR imaging of the head.

The next few years will undoubtedly see a refinement of proton imaging technology and a broader data base will indicate to what extent proton relaxation parameters are able to detect and characterize disease. In addition, it is likely that imaging of other nuclei (e.g. 31P, 23Na, 19F) will become a reality, although it must be stated that due to their inherently lower sensitivity to NMR detection and/or lower physiological concentration, clinical images of nuclei other than 1H will undoubtedly have a low spatial resolution and may require relatively long imaging times [41]. Nonetheless, herein lies the exciting possibility of non-invasive metabolic or functional imaging [42]. The realm of NMR contrast agents is just beginning to be explored [43, 44], and developments in high-speed imaging [45] indicate useful applications in cardiology [46]. So whilst improvements in image quality can be expected, as was the case with X-ray CT, the application of NMR in medicine will diversify to yield information of a more specifically functional nature. This, together with the very low attendant biological risk [47], heralds a bright future for NMR in clinical diagnosis.