The ‘starry-sky artifact’ is one of the unique imaging artifacts associated with the parallel imaging or Compressed SENSE technique used in MRI. This artifact manifests as grainy, pixelated noise, often resembling small circular or semi-circular rings and streaks. The resulting image can resemble a starry night sky, with countless points of light scattered throughout. This artifact tends to be more prominent at the center of the image.

These artifacts are not consistently present and can vary in intensity and frequency. Their occurrence depends on factors such as the specific MRI sequence used and the settings of parallel imaging or Compressed SENSE, including factors like denoising levels. In sequences with low contrast-to-noise ratios, these artifacts may become more noticeable due to undersampling in the k-space.