A method of assessing a spatial frequency distribution within a sample comprising subjecting the sample to magnetic resonance excitation, receiving an echo signal from the sample while the sample is subjected to a magnetic field gradient, applying an invertible linear transform to the echo signal, identifying a region of interest in the transformed echo signal and deriving a corresponding window function, applying the window function (in the signal or transform domain) to the echo signal to remove echo signal coming from regions of the sample outside of the region of interest, and analyzing the one dimensional spatial frequency content in the windowed echo signal in order to access a one dimensional spatial frequency distribution within the region of interest within the sample without creating an image.