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The accuracy of a CT-based bone segmentation technique for measuring the range of motion of the joints in the ankle

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For measuring the in-vivo range-of-motion of the ankle joints, a semi-automated Computer Tomography based bone contour method (CT/BCM) was developed to determine the three-dimensional position and orientation of the bones... After acquiring a complete CT-scan with the foot in a position, the specimen was moved through the CT gantry, and two X-ray images were made... Bone contour detection was performed as described by Beimers, and RSA was performed according to Valstar... Helical axis parameters were calculated for tibiotalar and talocalcaneal joint motion from neutral to the extreme positions and between opposite extreme positions... The differences between CT/BCM and RSA were calculated for rotation around, translation along, the position and the direction of the helical axis... The difference between the CT/BCM technique and RSA in helical axis position and helical axis rotation was dependent on the amount of rotation (Figure 1)... Compared with RSA, the CT/BCM data registered a RMS difference of 0.26 degree for rotation about the helical axis, and 0.11 mm translation along the helical axis for tibiotalar motion between opposite extreme foot position... For talocalcaneal motion, these differences were 0.17 degree and 0.23 mm respectively... A cadaver specimen was used instead of a phantom, mimicking the in-vivo situation... A-priori known kinematics could not be applied, but comparison between the two techniques served as a fair estimate of the accuracy of the CT/BCM technique... The data suggest that the CT/BCM technique is as accurate or even more accurate than the RSA technique.

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Difference in helical axis position and helical axis orientation between the CT technique and RSA technique as functions of the rotation about the helical axis. Data of the tibiotalar and talocalcaneal joints were pooled.
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Figure 1: Difference in helical axis position and helical axis orientation between the CT technique and RSA technique as functions of the rotation about the helical axis. Data of the tibiotalar and talocalcaneal joints were pooled.

Mentions: The difference between the CT/BCM technique and RSA in helical axis position and helical axis rotation was dependent on the amount of rotation (Figure 1). By approximation, this relationship matched the model by Woltring [3]. Compared with RSA, the CT/BCM data registered a RMS difference of 0.26 degree for rotation about the helical axis, and 0.11 mm translation along the helical axis for tibiotalar motion between opposite extreme foot position. For talocalcaneal motion, these differences were 0.17 degree and 0.23 mm respectively.


The accuracy of a CT-based bone segmentation technique for measuring the range of motion of the joints in the ankle
Difference in helical axis position and helical axis orientation between the CT technique and RSA technique as functions of the rotation about the helical axis. Data of the tibiotalar and talocalcaneal joints were pooled.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2562115&req=5

Figure 1: Difference in helical axis position and helical axis orientation between the CT technique and RSA technique as functions of the rotation about the helical axis. Data of the tibiotalar and talocalcaneal joints were pooled.
Mentions: The difference between the CT/BCM technique and RSA in helical axis position and helical axis rotation was dependent on the amount of rotation (Figure 1). By approximation, this relationship matched the model by Woltring [3]. Compared with RSA, the CT/BCM data registered a RMS difference of 0.26 degree for rotation about the helical axis, and 0.11 mm translation along the helical axis for tibiotalar motion between opposite extreme foot position. For talocalcaneal motion, these differences were 0.17 degree and 0.23 mm respectively.

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

For measuring the in-vivo range-of-motion of the ankle joints, a semi-automated Computer Tomography based bone contour method (CT/BCM) was developed to determine the three-dimensional position and orientation of the bones... After acquiring a complete CT-scan with the foot in a position, the specimen was moved through the CT gantry, and two X-ray images were made... Bone contour detection was performed as described by Beimers, and RSA was performed according to Valstar... Helical axis parameters were calculated for tibiotalar and talocalcaneal joint motion from neutral to the extreme positions and between opposite extreme positions... The differences between CT/BCM and RSA were calculated for rotation around, translation along, the position and the direction of the helical axis... The difference between the CT/BCM technique and RSA in helical axis position and helical axis rotation was dependent on the amount of rotation (Figure 1)... Compared with RSA, the CT/BCM data registered a RMS difference of 0.26 degree for rotation about the helical axis, and 0.11 mm translation along the helical axis for tibiotalar motion between opposite extreme foot position... For talocalcaneal motion, these differences were 0.17 degree and 0.23 mm respectively... A cadaver specimen was used instead of a phantom, mimicking the in-vivo situation... A-priori known kinematics could not be applied, but comparison between the two techniques served as a fair estimate of the accuracy of the CT/BCM technique... The data suggest that the CT/BCM technique is as accurate or even more accurate than the RSA technique.

No MeSH data available.


Related in: MedlinePlus