Figure 3

Measurement of image noise for a planned left-sided diagnostic C5 nerve root injection in a 41-year-old woman (A) and a planned left-sided L5 nerve root injection in a 34-year-old man (B). Scans were acquired with standard dose (SD) in these two exemplary patient cases. Three measurements of cervical or psoas muscle attentuation values were derived from three circular regions of interest (ROIs).