[Effects of slice thickness and matrix size on MRI for signal detection].

High-resolution MRI with increased matrix size is becoming widely used. When matrix size is increased, the signal-to-noise ratio (SNR) decreases. To compensate for a poor SNR, a thick slice is often used. The purpose of this study was to assess whether slice thickness affects the signal detectability of MR images. Signal detectability was evaluated for various slice thicknesses using a contrast-detail phantom. The results showed that thinning slices led to increased signal detection but to decreased SNR because of higher contrast in the partial volume effect. In addition, increasing matrix size and slice thickness for high-resolution imaging led to a decrease in signal detection. It is necessary to consider voxel form for two-dimensional MR images and to recognize that cuboid voxels lead to increased signal detection.