Table IV.

Mean CT numbers (HU) of the 4.8 mm diameter reference nodules for three scans at each technique and the standard deviations of the mean CT numbers.

		High resolution		NLST		LTRC
	Nodule no.	Mean	Standard deviation	Mean	Standard deviation	Mean	Standard deviation
100 mg/cc	1	47.5	0.4	−88.3	11.8	74.1	12.6
	2	44.3	2.1	−78.7	20.4	73.5	6.9
	3	44.3	2.2	−68.2	7.8	72.7	12.2
	4	42.0	0.6	−66.2	6.6	60.2	0.6
	5	40.7	2.4	−72.6	10.5	70.9	7.4
Overall mean		43.8±2.6		−74.8±9.0		70.3±5.7
50 mg/cc	6	−2.8	1.5	−116.5	0.3	15.2	3.5
	7	−8.0	2.2	−127.1	4.6	8.6	2.3
	8	−10.2	0.4	−149.1	22.7	2.2	6.0
	9	−8.6	2.2	−141.1	2.0	17.7	0.6
	10	−8.9	0.8	−157.2	4.7	12.7	1.6
Overall mean		−7.7±2.8		−138.2±16.4		11.3±6.1