Table 3.

Mean ± 1 standard deviation (mm) for deviations of coordinates among nine target points in each dimension on each z-plane, compared with 3.0-Tesla MR imaging and CT for three types of cranial screws of different materials: aluminum (a), aluminum with tungsten tip (b), and titanium (c)

Table 3a
z-position	x	y	z
50	0.2 ± 0.2	1.5 ± 0.3	0.6 ± 0.4
75	0.2 ± 0.2	1.0 ± 0.2	1.0 ± 0.4
100	0.1 ± 0.1	0.8 ± 0.2	0.6 ± 0.4
125	0.1 ± 0.1	0.5 ± 0.2	0.5 ± 0.2
150	0.2 ± 0.1	0.4 ± 0.2	1.4 ± 0.4
Table 3b
z-position	x	y	z
50	0.2 ± 0.2	2.5 ± 0.4	1.1 ± 0.6
75	0.2 ± 0.1	1.4 ± 0.4	1.6 ± 0.9
100	0.2 ± 0.1	0.6 ± 0.4	1.0 ± 0.5
125	0.1 ± 0.1	0.6 ± 0.3	0.8 ± 0.4
150	0.1 ± 0.1	0.5 ± 0.2	1.2 ± 0.8
Table 3c
z-position	x	y	z
50	0.4 ± 0.2	4.7 ± 0.6	1.9 ± 0.4
75	0.5 ± 0.2	3.5 ± 0.5	2.0 ± 0.4
100	0.5 ± 0.3	1.4 ± 0.5	0.8 ± 0.4
125	0.6 ± 0.2	1.0 ± 0.4	1.0 ± 0.3
150	0.7 ± 0.2	1.1 ± 0.3	3.2 ± 0.5

The x- and y-coordinates were measured for Phantom A, and the z-coordinate was measured for Phantom B.