Table 5. Average control SD of gray values at 70 kVp and slope of the trend in control SD at 70 kVp, under the conditions “with” and “without metal” and “with” and “without MAR”.

		Control SD at 70 kVp	Slope at 70 kVp
Metal	MAR	Mean ± SE	Slope ± SE
Without	Without	2.3 ± 0.2	−0.10 ± 0.01
	With	2.2 ± 0.2	−0.08 ± 0.01
With	Without	2.5 ± 0.2	−0.10 ± 0.01
	With	2.0 ± 0.2	−0.08 ± 0.01

MAR, metal artefact reduction; SD, standard deviation; SE, standard error.