Table 2:

Group comparisons between selected CT-acquisition parameters for patients receiving CT-guided spinal injections in 2009 and 2010^a

Parameter	Anatomy	2009	2010	T Test P Value
Minimum guide-phase tube current (mA)	All studies	75.0 ± 61.2	13.4 ± 7.3	<.001
	Cervical only	104.0 ± 68.2	16.7 ± 11.2	<.001
	Lumbar only	37.7 ± 29.0	11.7 ± 4.9	<.001
Total image series^b	All studies	12.3 ± 5.8	9.7 ± 5.4	.022
	Cervical only	14.0 ± 6.1	10.9 ± 4.6	.178
	Lumbar only	10.8 ± 3.3	9.3 ± 4.9	.269
Survey scan length (mm)	All studies	100.4 ± 36.4	94.5 ± 38.9	.436
	Cervical only	90.9 ± 56.6	56.6 ± 20.3	.088
	Lumbar only	108.0 ± 103.0	103.0 ± 40.0	.816

↵a Mean ± SD.
↵b Note, only 1 series each was assigned to the survey and contrast phases of the procedure; the remainder was during the guide phase.