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High resolution x-ray: a reliable approach for quantifying osteoporosis in a rodent model.

Velasco O, James AW, Asatrian G, Ajalat M, Pritchard T, Novshadian S, Murthy A, Bayani G, Zhang X, Ting K, Soo C - Biores Open Access (2014)

Bottom Line: It was observed that SHAM animals maintained a relatively constant bone mineral density (BMD), in comparison to OVX animals, whereby a significant decrease in BMD was appreciated.Post mortem X-ray scans were performed and converted to 8-bit color and quantified.A high level of agreement with DXA quantifications was observed with X-ray quantifications, and a significant correlation between the radiopacity, visualized by color distributions, and the DXA BMD values between animal groups was evident.

View Article: PubMed Central - PubMed

Affiliation: Dental and Craniofacial Research Institute and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, California. ; Department of Orthopaedic Surgery and the Orthopaedic Hospital Research Center, UCLA and Orthopaedic Hospital, University of California , Los Angeles, California. ; Department of Surgery, University of Maryland Medical Center , Baltimore, Maryland.

ABSTRACT
Osteoporosis is the most common metabolic disease of bone, resulting in significant worldwide morbidity. Currently, there are insufficient imaging modalities available to evaluate osteoporotic bones in small animal models. Here, we demonstrate the feasibility of using high resolution X-ray imaging as a comparable measure of bone degeneration to dual-energy X-ray absorptiometry (DXA) in an osteoporosis rodent model. At week 0, animals underwent either an ovariectomy (OVX) or sham procedure (SHAM). DXA analysis was performed weekly to confirm and compare the bone degenerative changes induced by OVX. A comparison using high resolution X-ray imaging (Faxitron(®)) was then performed postmortem due to need of soft tissue removal. Two regions of interest (ROIs) were utilized: the distal third of the femur and the lumbar spine (L4/L5). It was observed that SHAM animals maintained a relatively constant bone mineral density (BMD), in comparison to OVX animals, whereby a significant decrease in BMD was appreciated. Post mortem X-ray scans were performed and converted to 8-bit color and quantified. A high level of agreement with DXA quantifications was observed with X-ray quantifications, and a significant correlation between the radiopacity, visualized by color distributions, and the DXA BMD values between animal groups was evident. Our study demonstrates the applicability of high resolution X-ray imaging both qualitatively and quantitatively as a reliable approach for quantifying osteoporosis in rodent osteoporotic models. With DXA being a highly user dependent modality, our technique is a unique secondary methodology to verify DXA findings and minimize inter-observer variability.

No MeSH data available.


Related in: MedlinePlus

DXA scans of (A) distal femur and (B) lumbar spine exhibit a significant and gradual decrease in bone mineral density (BMD) in the ovariectomized (OVX) animals when compared with control. Qualitative (C) and quantitative analysis of (D, E) OVX animals revealed significant decreases in BMD by 1–2 weeks in both the femur and lumbar vertebrae regions of interest respectively. (F) Postmortem Faxitron scans of animals' femurs were next performed and converted to (G) 16-bit color. (H) Quantifications for relative radiolucency in the femur. (I, J, K) Identical protocol was performed for L5–L6 vertebrae. *p<0.05; **p<0.01.
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f2: DXA scans of (A) distal femur and (B) lumbar spine exhibit a significant and gradual decrease in bone mineral density (BMD) in the ovariectomized (OVX) animals when compared with control. Qualitative (C) and quantitative analysis of (D, E) OVX animals revealed significant decreases in BMD by 1–2 weeks in both the femur and lumbar vertebrae regions of interest respectively. (F) Postmortem Faxitron scans of animals' femurs were next performed and converted to (G) 16-bit color. (H) Quantifications for relative radiolucency in the femur. (I, J, K) Identical protocol was performed for L5–L6 vertebrae. *p<0.05; **p<0.01.

Mentions: DXA scans were performed weekly to confirm the induction of osteoporosis. Bone mineral density (BMD) measurements were obtained from scans at two ROIs: the distal one-third of the femur and the lumbar spine (L4–L5). SHAM-operated animals maintained relatively constant BMD, ranging between 98–113% of their initial values. In contrast, a significant decrease was observed by 4 weeks post-OVX in the distal femur (Fig. 2A) and by 2 weeks post-OVX in the lumbar spine (Fig. 2B). OVX-induced osteoporosis was confirmed at 5 weeks postoperative in OVX animals by a 7%–8% decrease, compared with preoperative BMD, measured at both the distal femur and lumbar spine ROIs, consistent with the previous studies.8–10


High resolution x-ray: a reliable approach for quantifying osteoporosis in a rodent model.

Velasco O, James AW, Asatrian G, Ajalat M, Pritchard T, Novshadian S, Murthy A, Bayani G, Zhang X, Ting K, Soo C - Biores Open Access (2014)

DXA scans of (A) distal femur and (B) lumbar spine exhibit a significant and gradual decrease in bone mineral density (BMD) in the ovariectomized (OVX) animals when compared with control. Qualitative (C) and quantitative analysis of (D, E) OVX animals revealed significant decreases in BMD by 1–2 weeks in both the femur and lumbar vertebrae regions of interest respectively. (F) Postmortem Faxitron scans of animals' femurs were next performed and converted to (G) 16-bit color. (H) Quantifications for relative radiolucency in the femur. (I, J, K) Identical protocol was performed for L5–L6 vertebrae. *p<0.05; **p<0.01.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4120930&req=5

f2: DXA scans of (A) distal femur and (B) lumbar spine exhibit a significant and gradual decrease in bone mineral density (BMD) in the ovariectomized (OVX) animals when compared with control. Qualitative (C) and quantitative analysis of (D, E) OVX animals revealed significant decreases in BMD by 1–2 weeks in both the femur and lumbar vertebrae regions of interest respectively. (F) Postmortem Faxitron scans of animals' femurs were next performed and converted to (G) 16-bit color. (H) Quantifications for relative radiolucency in the femur. (I, J, K) Identical protocol was performed for L5–L6 vertebrae. *p<0.05; **p<0.01.
Mentions: DXA scans were performed weekly to confirm the induction of osteoporosis. Bone mineral density (BMD) measurements were obtained from scans at two ROIs: the distal one-third of the femur and the lumbar spine (L4–L5). SHAM-operated animals maintained relatively constant BMD, ranging between 98–113% of their initial values. In contrast, a significant decrease was observed by 4 weeks post-OVX in the distal femur (Fig. 2A) and by 2 weeks post-OVX in the lumbar spine (Fig. 2B). OVX-induced osteoporosis was confirmed at 5 weeks postoperative in OVX animals by a 7%–8% decrease, compared with preoperative BMD, measured at both the distal femur and lumbar spine ROIs, consistent with the previous studies.8–10

Bottom Line: It was observed that SHAM animals maintained a relatively constant bone mineral density (BMD), in comparison to OVX animals, whereby a significant decrease in BMD was appreciated.Post mortem X-ray scans were performed and converted to 8-bit color and quantified.A high level of agreement with DXA quantifications was observed with X-ray quantifications, and a significant correlation between the radiopacity, visualized by color distributions, and the DXA BMD values between animal groups was evident.

View Article: PubMed Central - PubMed

Affiliation: Dental and Craniofacial Research Institute and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, California. ; Department of Orthopaedic Surgery and the Orthopaedic Hospital Research Center, UCLA and Orthopaedic Hospital, University of California , Los Angeles, California. ; Department of Surgery, University of Maryland Medical Center , Baltimore, Maryland.

ABSTRACT
Osteoporosis is the most common metabolic disease of bone, resulting in significant worldwide morbidity. Currently, there are insufficient imaging modalities available to evaluate osteoporotic bones in small animal models. Here, we demonstrate the feasibility of using high resolution X-ray imaging as a comparable measure of bone degeneration to dual-energy X-ray absorptiometry (DXA) in an osteoporosis rodent model. At week 0, animals underwent either an ovariectomy (OVX) or sham procedure (SHAM). DXA analysis was performed weekly to confirm and compare the bone degenerative changes induced by OVX. A comparison using high resolution X-ray imaging (Faxitron(®)) was then performed postmortem due to need of soft tissue removal. Two regions of interest (ROIs) were utilized: the distal third of the femur and the lumbar spine (L4/L5). It was observed that SHAM animals maintained a relatively constant bone mineral density (BMD), in comparison to OVX animals, whereby a significant decrease in BMD was appreciated. Post mortem X-ray scans were performed and converted to 8-bit color and quantified. A high level of agreement with DXA quantifications was observed with X-ray quantifications, and a significant correlation between the radiopacity, visualized by color distributions, and the DXA BMD values between animal groups was evident. Our study demonstrates the applicability of high resolution X-ray imaging both qualitatively and quantitatively as a reliable approach for quantifying osteoporosis in rodent osteoporotic models. With DXA being a highly user dependent modality, our technique is a unique secondary methodology to verify DXA findings and minimize inter-observer variability.

No MeSH data available.


Related in: MedlinePlus