"Starry-sky artifact in parallel imaging MRI (e.g. SENSE) is relatively common, and typically encountered as non-uniform distribution of image noise, typically affecting the centre part of the image (being more distant from the surface coils) more than the superficial tissues. Note that many other forms of artifacts can be encountered in parallel imaging such as ghosting, and aliasing, but these are not unique to these sequences."
Expected headings
"Physics"
"Noise in parallel imaging is unevenly distributed but is highly dependent on a spatial parameter, the geometric (g) factor. It also increases with the use of higher acceleration (R) factors. The result is the inhomogeneous distribution of low signal-to-noise ratios (SNR) areas. Regions more distant of surface coils (e.g. the deep tissues of a larger patient) are more prone to this artifact. Downward adjustment of the R factor during scanning may improve SNR, but will significantly increase scan time 1. Sometimes repeating the sequence can alone diminish the artifact 2."