雙能量Ｘ光骨質密度吸收測量儀掃描腰椎和兩側股骨在臨床上的應用

The Clinical Application of Dual-energy X-ray Absorptiometry in the Lumbar Spine and Femurs

范志明(Chih-Ming Fan)

指導教授 ： 華亦熙 ； 陳芳萍 ； 陳志華

中臺科技大學/健康科學院/放射科學研究所/碩士(2010年)

摘要

雙能量X光骨質密度吸收測量儀(dual-energy x-ray absorptiometry, DXA)掃描腰椎及兩側髖部，可提供臨床醫師做為治療骨質疏鬆症(osteoporosis)的重要依據。病患進行多次的骨質密度(bone mineral density, BMD)掃描，其結果之間的變動是否具有生物意義與放射師有關，BMD精密度檢測(precision assessment)的精密度誤差值(precision error, PE)，可以檢定一位放射師對同一位病患使用相同的設備，在這一次和下一次的BMD檢測中，是否得到良好再現性的能力(reproducibility)，而最小顯著變化值(least significant change, LSC)，可以提供臨床醫師在診斷病患多次BMD掃描結果間的變動，是否具有生物性變化意義的判斷指標。因此，為了瞭解放射師操作的PE值是否符合國際臨床骨密度儀協會(the International Society for Clinical Densitometry, ISCD)的建議及腰椎與髖部的BMD和T-score及Z-score之間的差異，本實驗共安排了150位，年齡介於35-50歲、身心健康、沒有懷孕、沒有骨折、腰椎及兩側髖關節正常，且無服用影響骨骼代謝藥物的自願參加實驗的受試者進行precision assessment，分配給五位資深放射師，每人30位受試者，每位受試者掃描二次腰椎及兩側髖部掃描。以ISCD所建立全世界公認的精密計算公式，計算出BMD的PE值及LSC值，這些數值都必須符合ISCD的建議。結果發現，五位放射師平均的PE值為0.0076 g/cm2符合ISCD的建議範圍內，LSC值平均為0.0214 g/cm2，此平均的LSC值可提供臨床醫師判斷osteoporosis治療成效重要依據。另外，將受試者的Z-score進行統計分析，其腰椎大於兩側髖部(p<0.05)。因此建議在臨床檢查BMD時，應掃描3個部位(腰椎及兩側髖部)，以利正確的臨床的診斷。

關鍵字

腰椎 ； 髖部 ； 最小顯著變化 ； 精密度誤差 ； 精密度檢測 ； 雙能量X光骨質密度吸收測量儀

並列摘要

Dual-energy X-ray absorptiometry(DXA) scans of the lumbar spine and hips are currently the gold-standard for measurement of bone mineral density (BMD), which can provide clinicians with the treatment of osteoporosis. Recently, we most common measure the BMD of lumbar spine and hip. Therefore, clinicians arrange patients to accept several times of BMD scans, and the difference in BMD relevant to radiographers is biologically significant. In precision assessment of BMD, we measure the precision error (PE) which can be determined for a single radiographer who has the excellent reproducibility on the same machine and the same patient between BMD scans. Least significant change (LSC) can provide clinicians for estimating the patient’s BMD changes whether it is biologically significant. As a result, precision assessment was determined on 150 volunteers who aged 35 to 50 years old, physical and moral integrity, no pregnant, and no fractures normal lumbar spine and hips structures and no took medicine which can affect bone metabolism. 150 volunteers were assigned to five senior radiographers. Each radiographer had to be responsible for 30 volunteers. 150 volunteers were scanned two times each for the lumbar spine and both hips. According to the worldwide recognized formulas established by ISCD, we analyzed the scan results to measure the PE, and used the PE to calculate LSC to further understand the precision error within radiographers. All the PE and LSC values should conform to the recommendations of ISCD. In conclusion, the averaged PE of five radiographers was 0.0076 g/cm2, which is consistent with the recommendations of ISCD; the averaged LSC 0.0214 g/cm2 then could be standard clinical practice for clinicians to treat and follow up patients with osteoporosis. Otherwise, we analyzed the Z-score for 150 participants, and we found that the average Z-score of lumbar spine was higher than both hips(p<0.05). We suggested that we should measure not only the lumbar spine but also both hips in a clinical examination.

並列關鍵字

femur ； lumbar spine ； least significant change ； precision assessment ； precision error ； dual-energy x-ray absorptiometry

參考文獻

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