Thomas Ruan1 and Kayvan R. Keshari1,2,3 1Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA 2Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA 3Weill Cornell Graduate School, New York, New York 10065, USA Correspondence: rahimikkmskcc.org

Molecular imaging—the mapping of molecular and cellular processes in vivo—has the unique capability to interrogate cancer metabolism in its spatial contexts. This work describes the usage of the two most developed modalities for imaging metabolism in vivo: positron emission tomography (PET) and magnetic resonance (MR). These techniques can be used to probe glycolysis, glutamine metabolism, anabolic metabolism, redox state, hypoxia, and extracellular acidification. This review aims to provide an overview of the strengths and limitations of currently available molecular imaging strategies.