SpiralFFT is an ”effectively separable” transform that is designed to compute a 3-D FFT along spiral contours by a series of 1-D calculations. The application of interest for the transform is 3-D spiral MRI, which typically uses such Fourier contours. There are many difficulties in efficiently computing samples of the DTFT when the Fourier samples are not located on a uniform grid. Our algorithm consider special types of sampling grids that allow us to manipulate the mathematical equations of the Non-uniform DFT to obtain a semi-separable transform.