The effects of zero-filling in magnetic resonance imaging

Fast Fourier transform algorithms used by most MR manufacturers for two-dimensional Fourier transform (2D-FT) magnetic resonance imaging require a power of two number of sample points along the phase and frequency encoding directions. Zero-filling is a technique that allows smaller sample sizes to be used by adding zeroes to bring the data set to a full power of two. The effect of variable amounts of zero-filling on scan time, image signal-to-noise, contrast, and spatial resolution was empirically studied using phantoms and normal volunteers. Zero-filling allows a dramatic reduction in the MR scan time at the expense of decreased spatial resolution and increased truncation errors along the phase encoding axis. Unlike most other techniques for shortening 2D-FT scan times, zero-filling largely preserves the signal-to-noise response. 9 refs.; 4 figs.; 1 table