Lunar prodigy advance dxa

BMD at distal femoral metaphysic and proximal tibial metaphysic were measured by dual-energy X-ray absorptiometry (DXA) assay (Lunar Prodigy Advance DXA, GE healthcare, Madison, WI, USA) [32 (link)]. Data was calculated automatically by purpose-designed software (enCORE^TM 2006, GE Healthcare, Madison, WI, USA). Before measurement, rats were anesthetized by intraperitoneal injection with chloral hydrate at the dose of 300 mg/kg and fixed at repeatable positioning. Total BMD was measured including the cross-sectional area of both cortical and trabecular bones.

The body composition details (total-body bone mineral contents [BMC_TB], fat mass [FM], and lean mass [LM]), and the BMDs of total body (BMD_TB) and lumbar spine L1–L4 (BMD_LS) were measured using the Lunar Prodigy Advance DXA bone densitometer [General Electric (GE) Lunar Corporation, Madison, WI, USA] with a pediatric software (ver. enCORE 2005 9.15.010, GE Lunar Corp.). All measurements including each region of interest were carried out by a trained technician and underwent daily quality control assessment in accordance with the manufacturer’s standards. The BMD of total body less head (BMD_TBLH) was calculated via the total BMC of the trunk, upper limbs, and lower limbs, divided by the area of the same regions. The coefficients of variation for the BMD_TB, BMD_TBLH, and BMD_LS of 30 children with repeated measurements were 0.87%, 0.77%, and 1.20%, respectively. The Z-scores for FM, LM, BMC_TB, BMD_TB, BMD_LS, and BMD_TBLH (FM_Z, LM_Z, BMC_TB_Z, BMD_TB_Z, BMD_LS_Z, and BMD_TBLH_Z, respectively) were defined by the standard equation using age- and sex-matched reference values of Korean children and adolescents [27 (link), 28 (link)]. The Z-scores were computed as follows, (measured values–matched reference mean) / matched reference standard deviation.

After the rats were injected intraperitoneally with anesthesia and deeply anesthetized, they were neatly arranged on test bench of the bone densitometer. We scanned the whole body of the rats by the small animal scan mode using dual-energy X-ray absorptiometry (DEXA) assay (Lunar Prodigy Advance DXA, GE healthcare, Madison, WI, USA)^{23 (link)}. After all scans were completed, then we selected the femurs as the region of interest (ROI) to analyze the BMD value using GE’s purpose-designed software (enCORE 2006, GE Healthcare, Madison, WI, USA).