Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
Department of Radiology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.
Comput Methods Programs Biomed. 2018 Feb;154:79-88. doi: 10.1016/j.cmpb.2017.11.009. Epub 2017 Nov 16.
Flatfeet can be evaluated by measuring the calcaneal-fifth metatarsal angle on a weight-bearing lateral foot radiograph. This study aimed to develop an automated method for determining the calcaneal-fifth metatarsal angle on weight-bearing lateral foot radiograph.
The proposed method comprises four processing steps: (1) identification of the regions including the calcaneus and fifth metatarsal bones in a foot image; (2) delineation of the contours of the calcaneus and the fifth metatarsal; (3) determination of the tangential lines of the two bones from the contours; and (4) determination of the calcaneal-fifth metatarsal angle between the two tangential lines as arch angle.
The proposed method was evaluated using 300 weight-bearing lateral foot radiographs. The arch angles determined by the proposed method were compared with those measured by a radiologist, and the errors between the automatically and manually determined angles were used to evaluate the precision of the method. The average error in the proposed method was found to be 1.12° ± 1.57° In the study, in 73.33% of the cases, the arch angles could be determined automatically without redrawing any tangential lines; in 23.00% of the cases, the angles would be correctly determined by redrawing one of the tangential lines; further, in only 3.67% of the cases, both the calcaneal and fifth metatarsal tangential lines needed to be redrawn to determine the arch angles.
The results revealed that the proposed method has potential for assisting doctors in measuring the arch angles on weight-bearing lateral foot radiographs more efficiently.
在负重侧位足部 X 光片上测量跟骨-第五跖骨角可评估扁平足。本研究旨在开发一种自动确定负重侧位足部 X 光片上跟骨-第五跖骨角的方法。
该方法包括四个处理步骤：（1）识别足部图像中包括跟骨和第五跖骨的区域；（2）描绘跟骨和第五跖骨的轮廓；（3）从轮廓确定两条骨的切线；（4）确定两条切线之间的跟骨-第五跖骨角作为拱角。
该方法使用 300 张负重侧位足部 X 光片进行了评估。将所提出的方法确定的拱角与放射科医生测量的拱角进行比较，并使用自动和手动确定的角度之间的误差来评估方法的精度。该方法的平均误差为 1.12°±1.57°。在研究中，73.33%的情况下可以自动确定拱角，无需重新绘制任何切线；23.00%的情况下，只需重新绘制一条切线即可正确确定角度；仅在 3.67%的情况下，需要重新绘制跟骨和第五跖骨切线来确定拱角。
结果表明，该方法有可能帮助医生更有效地测量负重侧位足部 X 光片上的拱角。
