Title
Reliable measurement of 3D foot bone angles based on the frame-of-reference derived from a sole of the foot.
Abstract
Clinical management of foot pathology requires accurate and robust measurement of the anatomical angles. In order to measure a 3D angle, recent approaches have adopted a landmark-based local coordinate system to establish bone angles used in orthopedics. These measurement methods mainly assess the relative angle between bones using a representative axis derived from the morphological feature of the bone and therefore, the results can be affected by bone deformities. In this study, we propose a method of deriving a global frame-of-reference to acquire consistent direction of the foot by extracting the undersurface of the foot from the CT image data. The two lowest positions of the foot skin are identified from the surface to define the base plane, and the direction from the hallux to the fourth toe is defined together to construct the global coordinate system. We performed the experiment on 10 volumes of foot CT images of healthy subjects to verify that the proposed method provides reliable measurements. We measured 3D angles for talus-calcaneus and talus-navicular using facing articular surfaces of paired bones. The angle was reported in 3 projection angles based on both coordinate systems defined by proposed global frame-of-reference and by CT image planes (saggital, frontal, and transverse). The result shows that the quantified angle using the proposed method considerably reduced the standard deviation (SD) against the angle using the conventional projection planes, and it was also comparable with the measured angles obtained from local coordinate systems of the bones. Since our method is independent from any individual local shape of a bone, unlike the measurement method using the local coordinate system, it is suitable for inter-subject comparison studies.
Year
DOI
Venue
2016
10.1117/12.2217388
Proceedings of SPIE
Keywords
Field
DocType
foot and ankle,3D angle measurement,frame-of-reference
Coordinate system,Computer vision,Transverse plane,Articular surfaces,Global coordinate system,Fourth toe,Artificial intelligence,Landmark,Standard deviation,Frame of reference,Physics
Conference
Volume
ISSN
Citations 
9785
0277-786X
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Taeho Kim193.27
Dong-Yeon Lee201.35
Jinah Park334859.89