Single-point imaging with a variable phase encoding interval

A modified single-point imaging (SPI) technique using a variable phase encoding interval is proposed. This method is based on the minimization of the phase encoding interval for further signal-to-noise ratio (SNR) optimization. This is particularly beneficial when the maximum gradient amplitude limits an optimal phase encoding interval, and the resulting SNR suffers from T2-related signal attenuation. Theoretical calculation of the SNR and simulation of the point spread function (PSF) for the different experimental parameters are presented. Experiments using a rubber sample (T2*∼73 μs) and a tooth (bi-exponential relaxation: T2,1*=111 μs and T2,1*=872 μs) showed a significant increase in SNR (>3 and >2, respectively) when compared with images acquired with conventional SPI.