Assessing tissue metabolism by phosphorous-31 magnetic resonance spectroscopy and imaging: a methodology review.

Many human diseases are caused by an imbalance between energy production and demand. Magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide the unique opportunity for assessment of several fundamental events in tissue metabolism without the use of ionizing radiation. Of particular interest, phosphate metabolites that are involved in ATP generation and utilization can be quantified noninvasively by phosphorous-31 (P) MRS/MRI. Furthermore, P magnetization transfer (MT) techniques allow measurement of metabolic fluxes via creatine kinase (CK) and ATP synthase. However, a major impediment for the clinical applications of P-MRS/MRI is the prohibitively long acquisition time and/or the low spatial resolution that are necessary to achieve adequate signal-to-noise ratio. In this review, current P-MRS/MRI techniques used in basic science and clinical research are presented. Recent advances in the development of fast P-MRS/MRI methods are also discussed.