A Closed-Form Expression for Ultimate Intrinsic Signal-To-Noise Ratio in MRI

Emre Kopanoglu¹, Vakur B. Erturk¹, Ergin Atalar¹

Calculating the ultimate intrinsic signal-to-noise ratio (UISNR), which gives the lowest upper bound on SNR excluding the effect of imaging parameters, requires a complicated analysis. In this study, a closed-form expression for UISNR in a cylindrical body is derived, and the dependence of UISNR on geometric and electromagnetic properties of the body of interest is shown explicitly. Using the formulation given, UISNR can easily be calculated. The derived expression is applicable to small animal imaging, MR microscopy, high-field NMR spectroscopy and human imaging up to 1.5T.