Introduction to in vivo MRS of cancer: new perspectives and open problems

Measurements of tumour extracts and tumour cell lines using 1H and 31P MRS have demonstrated the potential of the technique to distinguish different types of tumour, and in a range of tumours to provide information on degree of malignancy, grade and prognosis. In vivo studies have shown that changes in the energetic status of tumours, and in the phospholipid metabolites, correlate with the response of tumours to treatment, providing the potential to monitor the effectiveness of cancer treatment. Routine application of these techniques in clinical measurements depends upon the development of robust equipment and measurement methods to aid clinical measurements. Considerable advances have been made. Imaging can now be performed very rapidly, and a range of localisation technique have been established. Equipment provides for automatic set up and shimming, and coils with increased sensitivity are available. Improvements in hardware provide more sensitive receive coils; and shielded gradients which provide for a more robust performance. 31P studies are being improved by the use of NOE enhancement and 1H decoupling, increasing the specificity and sensitivity of the techniques. These advances in instrumentation need to be complemented by advances in our understanding of the biochemical processes in tumours giving rise to the observed spectral changes. In this paper, recent reports of NMR spectroscopy in cancer are reviewed, together with the requirements for tumour measurements.