Yee Kai Tee1, Alexandr A. Khrapichev2, Nicola R. Sibson2, Stephen J. Payne1, Michael A. Chappell1, 3
1Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, Oxfordshire, United Kingdom; 2Department of Oncology, CR-UK/MRC Gray Institute for Radiation Oncology & Biology, University of Oxford, Oxford, Oxfordshire, United Kingdom; 3Oxford Centre for Functional MRI of the Brain, University of Oxford, Oxford, Oxfordshire, United Kingdom
Pulsed CEST (PC) is the only feasible irradiation scheme for clinical application as a result of SAR and hardware limitations but there is no simple analytical solution available. Thus, it is typically treated as continuous CEST (CC) by finding its equivalent average field or power to exploit the closed-form analytical solution of CC. Although fitting the data by discretizing the short pulses used by PC is able to produce smaller fitted errors, there is no significant difference found for the important fitted parameters such as amide proton exchange rate (related to pH) when CC approximation, which is fast, is used.