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High resolution in vivo micro‐computed tomography is preferential over dual energy X‐ray absorptiometry for detecting bone loss in the orchidectomized guinea pig
Author(s) -
Mak Ivy Lynn,
DeGuire Jason R,
Lavery Paula,
Agellon Sherry,
Weiler Hope A
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1084.3
Subject(s) - dual energy x ray absorptiometry , medicine , in vivo , bone mineral , nuclear medicine , ex vivo , bone mineral content , osteoporosis , pathology , biology , microbiology and biotechnology
Monitoring longitudinal skeletal changes in small animals requires sensitive and precise imaging tools. This study compares two in vivo imaging modalities, dual energy X‐ray absorptiometry (DXA) and micro‐computed tomography (μCT) for assessing bone quality in the guinea pig. Middle‐aged male guinea pigs (n=40; 70 wks) were randomized into orchidectomized (ORX) or SHAM groups for 16 weeks. At termination, femurs were scanned in vivo using DXA (DXA in vivo , QDR 4500A, Hologic). Excised bones were scanned again using DXA (DXA ex vivo ), and μCT (LCT‐200, Aloka). Bone mineral content (BMC) was assessed by ashing. Independent t test was used to compare differences in SHAM vs ORX; and agreement between methods assessed with Bland‐ Altman plots. Substantial bias (7–60%) was observed in all measured variables except areal bone mineral density (aBMD). As shown by DXA in vivo and μCT, whole bone aBMD was significantly higher in SHAM vs ORX. DXA in vivo also suggested higher BMC but smaller bone in SHAM vs ORX, such differences were not observed in DXA ex vivo , μCT or ashing; indicating the lower aBMD in ORX observed in DXA in vivo is likely an artifact resulting from variations in nearby tissues and positioning. Also, compartmental changes in volumetric BMD and bone volume fraction shown by μCT are masked if only DXA was used. These data suggest that μCT is a more sensitive and reliable tool for capturing skeletal changes in the guinea pig.