The Positive And Negative Effects Of Exogenous Fat To The Bone Mineral Density Measurement In Healthy Women By DXA

Chapter One Influence of exogenous fat to the measurement of bone mineral density by DXAObjective:To examine the influence of exogenous fat(lard) to the BMD of lumbar spine on a phantom measured by DXA Hologic QDR 4500A.Materials and methods:The lumbar spine(LS) DXA scans were performed on a lumbar spine phantom,and the bone mineral density (BMD) of LS were repeated when with lard packets(5cm thick or 10cm thick).We used pair t-test to compare the value of LS BMD without and with lard placed on the phantom.Results:The bone area(BA),bone mineral content(BMC),and BMD all decreased after the 5cm-thick lard packets placed,and the BMD of L1 decreased significantly(p＜0.05);Besides,when with the 10cm-thick lard packet,the BA,BMC,as well as BMD all decreased significantly(p＜0.05-p＜0.01).Conclusion:We can conclude that the exogenous lard impacted LS BMD of lumbar spine phantom by DXA Hologic QDR 4500A,with significant decrease of the measured value.However,this impact would result anomaly measurements of BMD on obese people,and even their incorrectly diagnosis of osteoporosis. Chapter Two The positive and negative effects of exogenous fat to the bone mineral densitymeasurement in healthy women by DXAObjective:To examine the influence of exogenous fat(lard) to the BMD of lumbar spine measured by DXA Hologic QDR 4500A in different sites of healthy women.Materials and methods:Lard packets(5cm thick or 10cm thick) were prepared.The lumbar spine(LS) DXA scans were performed on 37 women,and were repeated when with lard packets(5cm thick or 10cm thick) placed over the abdomen.The hip DXA scans were performed on 18 women,and were repeated with lard packets(5cm thick or 10cm thick) placed over the left thigh.And the whole body DXA scans were performed on 8 women,then were repeated when with 5cm-thick lard packets over the abdomen.Results:After lard placed,the bone area(BA),bone mineral content (BMC),and BMD of LS all decreased significantly(p＜0.001);At the site of hip,the BMD all increased significantly(p＜0.05-p＜0.01).However,the BMD of the whole body had no significant change.Conclusion:We can conclude that the exogenous lard impacted the BMD of women by DXA Hologic QDR 4500A,with significant decrease of the measured value on LS and increase of the measured value at the site of hip,but no significant change of the whole body BMD.