Table 4:

Results of quantitative image-quality analysis^{^a}

Variables	120-kV	70-kV	P Value
Spinal cord
CT number (HU)	39.4 ± 7.1	54.3 ± 11.6	<.001^{^b}
SD (HU)	12.5 ± 3.4	13.7 ± 3.9	.059
Bone cortex around the vertebral foramen
CT number (HU)	657.4 ± 134.0	1,106.1 ± 246.2	<.001^{^b}
Anterior spinal artery
CT number (HU)	78.7 ± 13.3	127.7 ± 30.0	<.001^{^b}
CNR_ASA-Cord	3.4 ± 1.6	5.6 ± 2.5	<.001^{^b}
CNR_ASA-Bone	50.3 ± 17.0	75.9 ± 30.5	<.001^{^b}

Note:—CNR_ASA-Cord indicates contrast-to-noise ratio of the anterior spinal artery to the spinal cord; CNR_ASA-Bone, contrast-to-noise ratio of the anterior spinal artery to bone cortex around the vertebral foramen.
↵a Data are presented as the mean ± SD.
↵b Statistically significant.