Table 6.

pQCT and hr-pQCT Short-term Test-Retest Statistics

pQCT distal slice	Distal radius		Distal tibia
	RMSCV	RMSSD	RMSCV	RMSSD
BV/TV (fraction)	0.035	0.010	0.016	0.010
Tb.Sp (mm)	0.041	0.030	0.025	0.010
Tb.Sp MI (mm)	0.041	0.030	0.025	0.010
Tb.Th (mm)	0.040	0.010	0.017	0.010
Tb.Th MI (mm)	0.040	0.010	0.017	0.010
Tb.N (number/mm)	0.029	0.0	0.016	0.0
Ct.Th (mm)	0.050	0.040	0.050	0.060
vBMDi (mg/cm3)	0.050	0.06	0.052	0.07
vBMDc (mg/cm3)	0.070	18.57	0.026	7.98
vBMDtr (mg/cm3)	0.030	26.12	0.011	10.32

hr-pQCT volume	Radius		Tibia
	RMSCV	RMSSD	RMSCV	RMSSD
BV/TV (fraction)	0.007	0.001	0.004	<0.000
Tb.Sp (mm)	0.048	0.023	0.041	0.022
Tb.Th (mm)	0.046	0.003	0.037	0.003
Tb.N (mm−1)	0.048	0.09	0.041	0.07
Ct.Th (mm)	0.013	0.010	0.005	0.006
vBMDi (mg/cm3)	0.005	1.77	0.002	0.76
vBMDc (mg/cm3)	0.005	3.93	0.002	1.73
vBMDtr (mg/cm3)	0.007	1.01	0.004	0.69

Note: Distal radius and tibia scans obtained twice at the same study visit were analyzed for root mean square coefficients of variation (RMSCV) and root mean square standard deviations (RMSSD) in the present study for pQCT (above). A separate study of participants with a mean age of 44.2 yr (range, 20–69 yr) with 25 women and 6 men were scanned twice at the same study visit on the same hr-pQCT scanner used in the present study, also reporting RMSCV and RMSSD values (below). Reproduced with permission from Cheung et al (27).

Abbr: BV/TV, bone volume fraction; Ct.Th, cortical thickness; hr-pQCT, high-resolution peripheral quantitative computed tomography; MI, model-independent measures; pQCT, peripheral quantitative computed tomography; vBMDc, cortical volumetric bone mineral density; vBMDi, integral volumetric bone mineral density; vBMDtr, trabecular volumetric bone mineral density; Tb.N, trabecular number; Tb.Sp, trabecular separation; Tb.Th, trabecular thickness.