2D-3D Registration of CT Vertebra Volume to Fluoroscopy Projection: A Calibration Model Assessment

• Published in: EURASIP journal on advances in signal processing Vol. 2010; no. 1
• Main Authors: Bifulco, P., Cesarelli, M., Allen, R., Romano, M., Fratini, A., Pasquariello, G.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-01-2010; Springer Nature B.V; SpringerOpen
• Subjects: Accuracy; Engineering; Image Processing and Analysis in Biomechanics; Quantum Information Technology; Research Article; Signal,Image and Speech Processing; Spintronics; Studies; Calibration Model; Calibration Object; Fiducial Marker; Mass Attenuation Coefficient; Euler Angle
• ISSN: 1687-6180; 1687-6172; 1687-6180
• DOI: 10.1155/2010/806094

This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume) and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1 mm for displacements parallel to the fluoroscopic plane, and of order of 10 mm for the orthogonal displacement.