[Consideration on SNR in Synthetic MRI]

Synthetic magnetic resonance imaging (MRI) can create different contrast weighted images by quantifying the T₁, T₂, and proton density values of the subjects from a single series of scan data. It has not been clarified how the signal to noise ratio (SNR) of the synthesized image varies depending on imaging parameters. We investigated the change of SNR in synthesized MR images by the experiment using self-made phantom. The SNR ratio of synthesized image by synthetic MRI showed the same tendency as the theoretical values due to parameter change in N_y, N_x, slice thickness, number of excitations. However, as for BW, the SNR ratio tended to be different from the theoretical values in some cases. In addition, it was suggested that the SNR of the composite image has relevance to the quantitative accuracy of the T₁, T₂, and proton density values. We thought that this is due to the image acquisition process by synthetic MRI.