van 't Klooster R, Hendriks E A, Watt I, Kloppenburg M, Reiber J H C, Stoel B C
Department of Radiology, Division of Image Processing, Leiden University Medical Center, Leiden, The Netherlands.
Osteoarthritis Cartilage. 2008 Jan;16(1):18-25. doi: 10.1016/j.joca.2007.05.015. Epub 2007 Jul 16.
To quantify osteoarthritis (OA) by automatic measurement of the joint space width (JSW) in the finger joints in hand radiographs, and validate this against semi-quantitative scoring.
Forty subjects with primary OA at multiple sites were selected, 20 of which had no joint space narrowing (JSN) in the hand, and 20 had moderate to severe JSN. Conventional hand radiographs were acquired and the image set was split into a training and test set, for developing and evaluating the method, respectively. No methods to quantify the JSW automatically in OA exist; therefore a method was developed. First the semi-automatic image analysis program identifies the metacarpal and interphalangeal joints. Subsequently, the corresponding joint margins and measurement interval are determined. Finally the JSW is measured in millimetres as the average distance between the joint margins enclosed by the measurement interval. The success rates of different steps of the image analysis were evaluated and a comparison was made between the JSW and the semi-quantitative Osteoarthritis Research Society International score for JSN.
The success rates for the identification of the joint locations and margins were 97.5% and 64.2%, respectively. The JSW decreased with increasing semi-quantitative scores, but increased as the joint was severely damaged. The agreement between the JSW and the semi-quantitative score was confirmed by a significant correlation (R2=0.54 and P<0.01) while assessing hand pairs instead of individual joints.
The JSW measurement closely reflects semi-quantitative scoring of JSN. Therefore, this method is expected to offer a reproducible and accurate measurement of the JSW in OA.
通过对手部X光片中手指关节间隙宽度（JSW）进行自动测量来量化骨关节炎（OA），并与半定量评分进行验证。
选取40例多部位原发性OA患者，其中20例手部无关节间隙变窄（JSN），20例有中度至重度JSN。采集常规手部X光片，并将图像集分为训练集和测试集，分别用于方法的开发和评估。目前尚无在OA中自动量化JSW的方法；因此开发了一种方法。首先，半自动图像分析程序识别掌指关节和指间关节。随后，确定相应的关节边缘和测量区间。最后，以毫米为单位测量JSW，即测量区间所包围的关节边缘之间的平均距离。评估图像分析不同步骤的成功率，并比较JSW与国际骨关节炎研究学会关于JSN的半定量评分。
关节位置和边缘识别的成功率分别为97.5%和64.2%。JSW随着半定量评分的增加而降低，但随着关节严重受损而增加。在评估双手而非单个关节时，JSW与半定量评分之间的一致性通过显著相关性得到证实（R2 = 0.54，P < 0.01）。
JSW测量密切反映了JSN的半定量评分。因此，该方法有望为OA中的JSW提供可重复且准确的测量。
