An Experimental Study of a 3D Bone Position Estimation System Based on Fluoroscopic Images

Abstract

To compare a 3D preoperative planning image and fluoroscopic image, a 3D bone position estimation system that displays 3D images in response to changes in the position of fluoroscopic images was developed. The objective of the present study was to evaluate the accuracy of the estimated position of 3D bone images with reference to fluoroscopic images. Bone positions were estimated from reference points on a fluoroscopic image compared with those on a 3D image. The four reference markers positional relationships on the fluoroscopic image were compared with those on the 3D image to evaluate whether a 3D image may be drawn by tracking positional changes in the radius model. Intra-class correlations coefficients for reference marker distances between the fluoroscopic image and 3D image were 0.98–0.99. Average differences between measured values on the fluoroscopic image and 3D bone image for each marker corresponding to the direction of the bone model were 1.1 ± 0.7 mm, 2.4 ± 1.8 mm, 1.4 ± 0.8 mm, and 2.0 ± 1.6 mm in the anterior-posterior view, ulnar side lateral view, posterior-anterior view, and radial side lateral view, respectively. Marker positions were more accurate in the anterior-posterior and posterior-anterior views than in the radial and ulnar side lateral views. This system helps in real-time comparison of dynamic changes in preoperative 3D and intraoperative fluoroscopy images.

Comparison of 3D Bone Position Estimation Using QR Code and Metal Bead Markers

“…This is because the actual measurements of the distance between markers were larger for the QR code markers than for the metal bead markers (average measurements of actual distance between QR code markers were 95.6 ± 31.1 mm and 95.6 ± 33.2 mm for the fluoroscopic image and the 3D image, respectively; average measurements of actual distance between metal bead markers were 60.9 ± 16.3 mm and 62.0 ± 16.9 mm for the fluoroscopic image and the 3D image, respectively). Finally, there were larger differences in the tracking accuracy compared to the previous study [ 10 ]. This is due to the differences in the number of frames of the analyzed images.…”

“…However, there were better accuracies for tracking with the QR code markers after rotation. Three-dimensional bone position estimation systems using metal bead markers have been reported to have inferior localization accuracy in the lateral views compared to the anterior–posterior and posterior–anterior views [ 10 ]. The reason for the inferior accuracy in the lateral view is that the depth of the object cannot be detected from a two-dimensional perspective, and the proximity of the markers in the lateral view causes the distances between the markers on the 2D image to appear smaller than the actual distance.…”

“…We used the 3D position estimation and tracking program to detect reference points on the screen and track the motion of a fluoroscopic image as described by Yoshii et al [ 10 ]. This system is a program that outputs fluoroscopic images to a computer and can be operated on the computer.…”

“…The program was set up to track pre-specified reference markers. The metal bead marker tracking algorithm has been described previously [ 10 ]. In brief, the program is configured to automatically extract candidate marker points from the image and calibrate them by relating them to points on the 3D image.…”

“…We previously developed a 3D bone position estimation system that displays 3D images created before surgery in response to changes in the positions of metal bead markers on 2D dynamic fluoroscopic images during surgery [ 10 ]. The 3D bone image showed higher accuracy in the anterior–posterior and posterior–anterior views than in the lateral view.…”