Table 2.

Changes in bone mineral density (BMD) and trabecular bone microstructure parameters at reduced dose levels

BMD, mg/cm-3	Mean	SD	p-value	App. BF	Mean	SD	p-value
vs. original dose				vs. original dose
Proj50	+0.216	0.797	.197	Proj50	+0.024	0.034	.002
Proj25	+0.145	1.547	.650	Proj25	+0.036	0.052	.003
Proj10	+0.233	1.978	.569	Proj10	+0.035	0.055	.004
Tube50	+2.900	1.863	.000	Tube50	+0.037	0.032	.000
Tube25	+7.546	11.040	.003	Tube25	+0.057	0.072	.001
Tube10	+41.32	67.131	.006	Tube10	+0.094	0.120	.001
App. TbN, mm-1	Mean	SD	p-value	App. TbSp, mm	Mean	SD	p-value
vs. original dose				vs. original dose
Proj50	+0.058	0.025	.000	Proj50	-0.675	0.555	.000
Proj25	+0.089	0.066	.000	Proj25	-0.849	0.690	.000
Proj10	+0.038	0.047	.001	Proj10	-0.648	0.678	.000
Tube50	+0.046	0.027	.000	Tube50	-0.685	0.650	.000
Tube25	+0.082	0.048	.000	Tube25	-1.000	0.865	.000
Tube10	+0.104	0.091	.000	Tube10	-1.200	1.119	.000
App. TbTh, mm	Mean	SD	p-value	FD	Mean	SD	p-value
vs. original dose				vs. original dose
Proj50	-0.304	0.402	.001	Proj50	+0.059	0.045	.000
Proj25	-0.372	0.520	.002	Proj25	+0.081	0.062	.000
Proj10	-0.232	0.527	.042	Proj10	+0.067	0.061	.000
Tube50	-0.234	0.377	.006	Tube50	+0.063	0.051	.000
Tube25	-0.379	0.642	.008	Tube25	+0.103	0.083	.000
Tube10	-0.370	0.797	.033	Tube10	+0.137	0.133	.000

Values are shown as compared to the original dose in all subjects (n=24) with respective p-values

Proj50, Proj25 and Proj10 indicate sparse sampling of 50%, 25% and 10% projection data, respectively

Tube50, Tube25 and Tube10 indicate simulation of 50%, 25% and 10% of the original tube current, respectively

Displayed means and standard deviations (SD) are given in absolute values

App. apparent, BF bone fraction, BMD bone mineral density, FD fractal dimension, TbN trabecular number, TbSp trabecular separation, TbTh trabecular thickness