Optimizing Hadamard-Encoded 19F MRI for PFOB Imaging of Monocytes

Motivation: Perfluorooctyl bromide (PFOB) is a possible 19F tracer for monocytes active during myocardial infarction (MI). The method of Hadamard-encoding can mitigate chemical shift artifacts, but spectrally tailored pulses have not been leveraged yet. Goal(s): The goal of this work is to increase the SNR efficiency of the Hadamard-encoding method for 19F MRI of PFOB. Approach: Variable flipangle measurements were performed to measure T1 and the individual Hadamard-pulses were tailored to better fit the spectrum. Results: T1 values are similar for all PFOB resonances ranging between 870 and 970ms. SNR was increased by 10% by using a combination of Gaussian- and sinc-pulses. Impact: The improvements shown here contribute to making Hadamard-encoding a viable method for imaging PFOB with 19F MRI. As an alternative to monocyte tracking with PET, this might further our understanding of monocyte behavior during MI.