This study assessed the accuracy of marker-based kinematic analysis of the fingers, considering soft tissue artefacts (STA) and marker imaging uncertainty. We collected CT images of the hand from healthy volunteers with fingers in full extension, mid- and full-flexion, including motion capture markers. Bones and markers were segmented and meshed. The bone meshes for each volunteer's scans were aligned using the proximal phalanx to study the proximal interphalangeal joint (PIP), and using the middle phalanx to study the distal interphalangeal joint (DIP). The angle changes between positions were extracted. The HAWK protocol was used to calculate PIP and DIP joint flexion angles in each position based on the marker centroids. Finally the marker locations were 'corrected' relative to the underlying bones, and the flexion angles recalculated. Static and dynamic marker imaging uncertainty was evaluated using a wand. A strong positive correlation was observed between marker- and CT-based joint angle changes with 0.980 and 0.892 regression slopes for PIP and DIP, respectively, and Root Mean Squared Errors below 4°. Notably for the PIP joint, correlation was worsened by STA correction. The 95% imaging uncertainty interval was < ± 1° for joints, and < ± 0.25 mm for segment lengths. In summary, the HAWK marker set's accuracy was characterised for finger joint flexion angle changes in a small group of healthy individuals and static poses, and was found to benefit from skin movements during flexion.

中文翻译：

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量化手指运动捕获中的软组织假象和成像可变性。

这项研究考虑了软组织假象（STA）和标记物成像的不确定性，评估了基于标记物的手指运动学分析的准确性。我们收集了健康志愿者的手的CT图像，其手指处于全伸，中屈和全屈，包括运动捕捉标记。骨骼和标记被分割并划分网格。使用近端指骨对准近端指间关节（PIP），并使用中指骨对准远端指间关节（DIP），将每个志愿者扫描的骨网对齐。提取位置之间的角度变化。HAWK协议用于基于标记质心来计算每个位置的PIP和DIP关节弯曲角度。最终，标记位置相对于下面的骨骼进行了“校正”，并重新计算屈曲角度。使用魔杖评估静态和动态标记物成像的不确定性。在基于标记和基于CT的关节角度变化之间，PIP和DIP的回归斜率分别为0.980和0.892，且均方根误差低于4°，观察到了强正相关。尤其是对于PIP关节，相关性因STA校正而恶化。对于关节，95％的成像不确定性间隔为<±1°，对于段长度，其为<±0.25 mm。总而言之，HAWK标记集的准确性是针对一小群健康个体和静态姿势的手指关节弯曲角度变化进行表征的，发现它可以从弯曲期间的皮肤运动中受益。在基于标记和基于CT的关节角度变化之间，PIP和DIP的回归斜率分别为0.980和0.892，且均方根误差低于4°，观察到了强正相关。尤其是对于PIP关节，相关性因STA校正而恶化。对于关节，95％的成像不确定性区间为<±1°，对于段长度，其为<±0.25 mm。总而言之，HAWK标记集的准确性是针对一小群健康个体和静态姿势的手指关节弯曲角度变化进行表征的，发现它可以从弯曲期间的皮肤运动中受益。在基于标记和基于CT的关节角度变化之间，PIP和DIP的回归斜率分别为0.980和0.892，且均方根误差低于4°，观察到了强正相关。尤其是对于PIP关节，相关性因STA校正而恶化。对于关节，95％的成像不确定性间隔为<±1°，对于段长度，其为<±0.25 mm。总而言之，HAWK标记集的准确性是针对一小群健康个体和静态姿势的手指关节弯曲角度变化进行表征的，发现它可以从弯曲期间的皮肤运动中受益。和<±0.25毫米的段长度。总而言之，HAWK标记集的准确性是针对一小群健康个体和静态姿势的手指关节弯曲角度变化进行表征的，发现它可以从弯曲期间的皮肤运动中受益。和<±0.25毫米的段长度。总而言之，HAWK标记集的准确性是针对一小群健康个体和静态姿势的手指关节弯曲角度变化进行表征的，发现它可以从弯曲期间的皮肤运动中受益。