TABLE 1. Subject image quality parameters.
*Tumor-to-background is the ratio of the mean intensity of the tumor ROI drawn as described divided by the mean intensity of a 4 mm diameter spherical ROI drawn in background normal liver: TBR = SUVlesion/SUVbackground
#Signal-to-noise is defined as the mean intensity of the tumor ROI divided by the standard deviation of the normal liver back-ground ROI: SNR = SUVlesion/σbackground
& Contrast-to-noise is defined as the mean intensity of the tumor ROI above that in the normal liver background ROI, divided by the standard deviation of the normal liver background ROI: CNR = (SUVlesion – SUVbackground)/σbackground
Averages are the arithmetic mean plus or minus the standard deviation.