Lunar prodigy dxa scanner

A Lunar Prodigy DXA scanner (GE Healthcare Inc., Wisconsin, USA) was used to measure aBMD (g/cm²), fat mass (g) and lean mass (g) at specific regions of the body. Four scans were performed to obtain data for the whole body, LS (L1–L4) and dual hip scans. All DXA scans and subsequent in-software analyses were completed by the same researcher, using the same DXA scanner and the enCORE software version 14.10.022 (GE Healthcare Inc., Wisconsin, USA). Despite the coefficient of variation was not determined in the present study, precision studies in paediatric population have shown DXA’s coefficient of variations of 0.74% for total body less head (TBLH) aBMD and 0.64% for LS aBMD in 14–16 years late teens [26 (link)].

All measurements were done in the morning (before 10 am). Participants were asked to fast for at least 8 h prior to measurements and to avoid any intentional physical activity at the morning of the examination.
DSMF-BIA: Measurements were obtained using a InBody 770 body composition analyzer (Cerritos, CA, USA) in the standing position. Thirty bioimpedance measurements were based on six different frequencies (1 kH, 5 kHz, 50 kHz, 250 kHz, 500 kHz, 1000 kHz) at each body segment (right arm, left arm, trunk, right leg, and left leg).
DXA: DXA scan was performed using a Lunar Prodigy DXA scanner (GE Healthcare, Madison, WI, USA). Regional lean mass (kg), total-body fat (kg), and total-body fat percentage (%) were calculated using enCORE 2010 software platform version 13.31.016. Scan modes (thick, standard, or thin) were automatically set by the software. Scan times lasted approximately 5–10 min. All scan analyses were performed according to the manufacturer’s guidelines by the same technician (blinded to allocation) using standard analysis modules. In addition to total-body composition, regional estimates were made for the arms, legs, and trunk. This was accomplished by manually adjusting cut positions for each region of interest (ROI).
Appendicular skeletal mass index (ASMI) was calculated as the sum of the lean mass in the arms and legs divided by height squared (kg/m²).

Height was measured unshod to nearest 0.1 cm using a Harpenden Stadiometer and weight was measured in light clothing to the nearest 0.1 kg using a Tanita TBF 305 scales. Body mass index was calculated as weight (in kg)/height (in meters)². Estimates of total fat and lean body mass were made by DEXA scanner (Lunar Prodigy DXA scanner; GE Medical Systems, Madison, WI, USA). Blood draw following overnight fasting or a minimum of 6 h for afternoon/evening appointments, and biochemistry analysis of glucose and cholesterol including triglycerides, HDL, and LDL (not directly measured but calculated from total, HDL and triglycerides) cholesterol was undertaken following locally established procedures.

Growth data were collected by standardised routine measurements in annual clinics from ages 7 to 17 years (except ages 14 and 16 years). Age in months at clinic attendance was recorded.
Standing height was measured to the last complete millimetre using the Harpenden Stadiometer (Holtain Ltd, Crymych, UK) and weight was measured to the nearest 0.1 kg using the Tanita Body Fat Analyser (Model TBF 305, Tanita, Tokyo, Japan). Total body fat mass and total body lean mass was measured with dual-energy x-ray absorptiometry (Lunar Prodigy DXA scanner, GE Medical Systems, Madison, WI, USA) at ages 9, 11, 13, 15 and 17 years. Scans with anomalies (movement artefacts, artefacts caused by jewellery) were excluded. Within the three groups of picky children (not picky, somewhat picky, very picky) at each age, the children were categorised into BMI groups (thin (underweight)/normal/overweight/obese) using age- and sex-specific cut-offs [27 (link), 28 (link)]. The three thinness (underweight) categories (grades 1–3) were elided to form a single category for thinness; the overweight and obese categories were also elided to form a single category.

Lumbar spine BMD (anterior-posterior; L2-L4) and femoral neck BMD was measured by dual-energy X-ray absorptiometry (Lunar Prodigy DXA scanner; GE Medical Systems, Madison, Wisconsin, USA) and expressed in grams per square centimeter. Participant positioning and scan analysis procedures were standardized for all scans with CV < 0.01.
BMD was not measured in the hip fracture group (n = 92), a subgroup of the osteoporosis group, because the presence of hip fragility fracture met primary osteoporosis diagnostic criteria.

DXA scans of the periprosthetic bone were performed within the first postoperative week (baseline), and at 1 and 2 years, and cross-sectionally at 5 to 7 years using a Lunar Prodigy DXA Scanner (GE Healthcare, Waukesha, WI, USA). The patients were positioned supine with the leg in a foam frame to keep the knee semi-flexed by approximately 25° and the lower leg in neutral rotation (Stilling et al. 2010 (link)). Rice was applied around the knee as tissue-equivalent material and scans were performed with the “spine” mode. Analysis was performed in 3 regions of interest (ROI) (Figure 3) with a precision range from 1.8% to 3.7% for the anteroposterior scans, and from 3.4% to 6.2% for the lateral scans (Stilling et al. 2010 (link)).