Figure 21:

(a) Axial T1 and (b) axial STIR images. The most common artifact encountered is motion. This is usually involuntarily related to cardiac motion or respiration near the diaphragm (a) or bowel peristalsis lower in the abdomen (b). Motion artifact occurs in the phase encoding gradient (PEG), which is appropriately positioned along the Y-axis in the first image (a). PEG is incorrectly positioned along the X-axis in the second image (b), which is suboptimal due to the obscuration of the oblique musculature and site of injury (as denoted by the red arrow). Motion artifact can be limited using fast scanning techniques, shallow breathing instructions, prone positioning, passive restraints (such as tape, sandbags, and foam/rubber), and anxiety reduction techniques (such as music headphones and minimal sedation).