A B S T R A C T
Several new peripheral dual-energy X-ray absorptiometry (DXA) devices designed for assessment of bone and
body composition in rodents have been developed. We compared the performance (accuracy and precision) of
two of these devices, the InAlyzer and the iNSiGHT, to those of an established device, the PIXImus. We measured
total body bone mineral content (BMC), bone mineral density (BMD), and body composition (lean and fat mass)
on the three DXA devices in 18 male C57Bl/6 J mice (6 each of ages 8, 14, and 24 weeks, weighing 22 to 33 g).
DXA body composition measures were compared to whole-body nuclear magnetic resonance (NMR) outcomes.
BMC of the femur was also compared to ex vivo micro-computed tomography (microCT). Total body BMD from
the InAlyzer and iNSiGHT devices was strongly correlated to that from PIXImus (R2 = 0.83 and 0.82, respectively),
but was ~25 % higher than PIXImus. Total body BMC measures by InAlyzer were strongly associated
with those from PIXImus (R2 = 0.86), whereas those from iNSiGHT were only weakly correlated (R2 = 0.29).
Femur BMC from InAlyzer was strongly correlated with microCT outcomes, whereas iNSiGHT was only weakly
correlated. InAlyzer and iNSiGHT fat mass measures were very strongly correlated with PIXImus and NMR
outcomes (R2 = 0.91 to 0.97), with slightly weaker associations for lean mass (R2 = 0.81 to 0.76). Short-term
precision of InAlyzer and iNSiGHT measurements were excellent, and akin to those from the PIXImus for both
body composition and bone measures, ranging between 0.39 and 3.2 %. With faster scan times, closed X-ray
source and excellent precision, the new devices are both satisfactory replacements for the now discontinued
PIXImus system. However, given the accuracy of the bone and body composition measures, the InAlyzer may be
preferable for studies where musculoskeletal changes are the main interest.
