Table 3: Estimates of quantitative image quality parameters.

Mean value	220 mAs	350 mAs	p-value
SNR^a WM^b	7.8	11	0.04*
SNR GM^c	10.8	15.3	0.02*
CNR^d	1.7	2.5	0.008*
Mean value	240 mAs	350 mAs	p-value
SNR WM	9.27	9.8	0.2
SNR GM	12.2	13.4	0.3
CNR	2.1	2.3	0.4

^aSNR = signal-to-noise ratio

^bWM = white matter

^cGM = gray matter

^dCNR = contrast-to-noise ratio

*significant with p < 0.05