Abstract | There is currently increased focus on experimental medicine in drug development. Imaging methods potentially provide highly cost-effective, general approaches for the noninvasive characterisation of disease and pharmacokinetics, pharmacodynamics and drug effects directly in humans in ways that can enable this. The two methods most widely employed now are positron emission tomography (PET) and magnetic resonance imaging (MRI). PET allows the distribution of radiolabelled molecules to be mapped, enabling studies of molecule distribution and tissue metabolism. MRI was initially used primarily to define tissue structure, but a more recent range of functional MRI techniques promise the potential to define pharmacokinetic data over biologically meaningful timescales. With an understanding of the relationship between imaging biomarker changes and clinical outcomes, imaging can be used as a surrogate marker of response even for the later stages of drug development. There are pitfalls in the application of these methods, which need to be avoided. The two most common are: (i) getting distracted by the technology rather than focusing on the questions that need to be asked; and (ii) the failure to interpret the imaging data in an appropriate disease- and drug-specific fashion. However, with attention to such issues, imaging should prove a powerful facilitating platform for experimental medicine in the future. |
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