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Abstract #1926

On the Accuracy of AUC Ratio Method for Detecting Treatment Changes with Hyperpolarised 13C Dynamic Spectra

Deborah K. Hill1, Matthew R. Orton1, Martin O. Leach1, Yuen-Li Chung1, Thomas R. Eykyn1, 2

1CR-UK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom; 2Division of Imaging Sciences and Biomedical Engineering, Kings College London, St Thomas Hospital, London, United Kingdom

Signal enhancement from Dynamic Nuclear Polarisation allows estimation of apparent enzymatic rates in vivo in real-time. We have previously described a method for calculating metrics that are sensitive to treatment induced changes in the apparent forwards rate constant, based on AUC ratios of injected and generated metabolites (e.g. pyruvate and lactate). This AUC ratio approach is simpler and more robust than curve fitting using the modified Bloch equations, but suffers from bias. This theoretical abstract explores the assumptions required for the AUC ratio approach to be valid, and shows that the bias is less than 10% in a representative example.