Wang Ling, Huang Pengju, Du Hui, Geng Jian, Yin Xinghua, Liu Yandong, Puri Tanuj, He Bo, Lyu Liang, Cheng Xiaoguang, Jiang Xieyuan, Engelke Klaus, Blake Glen M
Department of Radiology, Beijing Jishuitan Hospital, Beijing, China.
Department of Radiology, The First People's Hospital of Yunnan Province, Kunming, China.
Quant Imaging Med Surg. 2022 Jun;12(6):3340-3350. doi: 10.21037/qims-21-842.
Radiographic absorptiometry (RA) is one of the earliest methods of bone densitometry and has been used to measure the phalanges and metacarpals where soft tissue attenuation is minimal. The aim of this study was to determine whether the technique can be adapted to correct for soft tissue attenuation and measure areal bone mineral density (aBMD) in the forearm.
A total of 51 patients referred for a clinical spine and hip dual-energy X-ray absorptiometry (DXA) examination and 8 young and middle-aged volunteers were recruited to this study. The first 29 participants (20 women, 9 men, aged 61±14 years) served as the training cohort, and the remaining 30 (20 women, 10 men, aged 55±16 years) comprised the validation cohort. All participants underwent a DXA scan of their non-dominant forearm, and a digital X-ray image of the same arm was acquired with a step phantom. Identical regions of interest (ROIs) in the radius and ulna at the one-third radius site were measured on the X-ray and DXA images, and a soft tissue ROI was measured on X-ray images between the radius and ulna. The X-ray measurements in the training cohort were expressed as equivalent step phantom thickness (Eq. SPT) and used to estimate forearm aBMD using a linear equation calibrated against the DXA scans. Estimates of forearm aBMD made from the digital X-ray images acquired in the validation cohort were compared with the results of the DXA scans.
Digital X-ray estimates of radius and ulna aBMD at the one-third radius site in the validation cohort showed a good correlation with GE-Lunar iDXA scanner measurements (r=0.795; P<0.001). The Bland-Altman plot had a mean bias of -0.002 g/cm and 95% limits of agreement of -0.185 to +0.181 g/cm.
Digital X-ray estimates of proximal forearm aBMD corrected for soft tissue attenuation correlated with DXA measurements with correlation coefficients comparable to those seen for other peripheral bone densitometry technologies.
放射吸收测定法（RA）是最早的骨密度测定方法之一，已被用于测量软组织衰减最小的指骨和掌骨。本研究的目的是确定该技术是否可用于校正软组织衰减并测量前臂的面积骨密度（aBMD）。
本研究共招募了51例因临床脊柱和髋部双能X线吸收测定法（DXA）检查而转诊的患者以及8名中青年志愿者。前29名参与者（20名女性，9名男性，年龄61±14岁）作为训练队列，其余（20名女性，10名男性，年龄55±16岁）组成验证队列。所有参与者均对其非优势前臂进行了DXA扫描，并用阶梯模体获取了同一手臂的数字X线图像。在X线和DXA图像上测量桡骨和尺骨在桡骨三分之一处相同的感兴趣区域（ROI），并在X线图像上测量桡骨和尺骨之间的软组织ROI。训练队列中的X线测量结果表示为等效阶梯模体厚度（Eq. SPT），并使用根据DXA扫描校准的线性方程来估计前臂aBMD。将验证队列中获取的数字X线图像得出的前臂aBMD估计值与DXA扫描结果进行比较。
验证队列中桡骨三分之一处桡骨和尺骨aBMD的数字X线估计值与GE-Lunar iDXA扫描仪测量值具有良好的相关性（r = 0.795；P < 0.001）。Bland-Altman图的平均偏差为-0.002 g/cm，95%一致性界限为-0.185至+0.181 g/cm。
校正软组织衰减后的近端前臂aBMD的数字X线估计值与DXA测量值相关，相关系数与其他外周骨密度测定技术相当。
