Table 5. Pearson Correlation Coefficients (R) between Radiation Dose Parameters and Image Quality Parameters.

	Slice Thickness-Normalized Image Noise	SNR	CNR	Subjective Image Quality Grade
CTDIvol before CT scan
Group 1	0.52 (p = 0.0004)	0.22 (p = 0.2)	0.17 (p = 0.3)	0.32 (p = 0.04)
Group 2	0.37 (p = 0.02)	0.01 (p = 0.9)	0.06 (p = 0.7)	0.19 (p = 0.2)
CTDIvol after CT scan
Group 1	0.49 (p = 0.001)	0.21 (p = 0.2)	0.16 (p = 0.3)	0.30 (p = 0.051)
Group 2	0.20 (p = 0.2)	0.22 (p = 0.2)	0.26 (p = 0.1)	0.06 (p = 0.7)
Effective mAs
Group 1	0.49 (p < 0.0001)	0.21 (p = 0.2)	0.16 (p = 0.3)	0.30 (p = 0.054)
Group 2	0.20 (p = 0.2)	0.23 (p = 0.2)	0.26 (p = 0.1)	0.06 (p = 0.7)
Quality reference mAs
Group 1	0.04 (p = 0.8)	0.04 (p = 0.8)	0.01 (p = 0.9)	0.09 (p = 0.6)
Group 2	0.05 (p = 0.8)	0.24 (p = 0.1)	0.23 (p = 0.1)	0.24 (p = 0.1)