MR spectroscopy: truly molecular imaging; past, present and future.

MR spectroscopy involves the examination of molecules in a much more transparent manner than does routine, clinical, conventional MR imaging. Its performance and interpretation goes back to the origins of MR imaging in nuclear magnetic resonance and also points to a future in which functional type techniques such as molecular imaging tell more than simple anatomy, but also the physiology of what is seen when looking at a patient's radiological images. A brief discussion of the past, present, and appreciation of MR spectroscopy as a molecular imaging modality. Several techniques, applications, and controversies aso are discussed in this article.