OBJECTIVE: Electromechanical devices enable increased accuracy in surgical procedures, and the recent development of MRI-compatible mechatronics permits the use of MRI for real-time image guidance. Integrated imaging of resonant micro-coil fiducials provides an accurate method of tracking devices in a scanner with increased flexibility compared to gradient tracking. Here we report on the ability of ten different image-processing algorithms to track micro-coil fiducials with sub-pixel accuracy. MATERIALS AND METHODS: Five algorithms: maximum pixel, barycentric weighting, linear interpolation, quadratic fitting and Gaussian fitting were applied both directly to the pixel intensity matrix and to the cross-correlation matrix obtained by 2D convolution with a reference image. RESULTS: Using images of a 3 mm fiducial marker and a pixel size of 1.1 mm, intensity linear interpolation, which calculates the position of the fiducial centre by interpolating the pixel data to find the fiducial edges, was found to give the best performance for minimal computing power; a maximum error of 0.22 mm was observed in fiducial localisation for displacements up to 40 mm. The inherent standard deviation of fiducial localisation was 0.04 mm. CONCLUSION: This work enables greater accuracy to be achieved in passive fiducial tracking.
OBJECTIVE: Electromechanical devices enable increased accuracy in surgical procedures, and the recent development of MRI-compatible mechatronics permits the use of MRI for real-time image guidance. Integrated imaging of resonant micro-coil fiducials provides an accurate method of tracking devices in a scanner with increased flexibility compared to gradient tracking. Here we report on the ability of ten different image-processing algorithms to track micro-coil fiducials with sub-pixel accuracy. MATERIALS AND METHODS: Five algorithms: maximum pixel, barycentric weighting, linear interpolation, quadratic fitting and Gaussian fitting were applied both directly to the pixel intensity matrix and to the cross-correlation matrix obtained by 2D convolution with a reference image. RESULTS: Using images of a 3 mm fiducial marker and a pixel size of 1.1 mm, intensity linear interpolation, which calculates the position of the fiducial centre by interpolating the pixel data to find the fiducial edges, was found to give the best performance for minimal computing power; a maximum error of 0.22 mm was observed in fiducial localisation for displacements up to 40 mm. The inherent standard deviation of fiducial localisation was 0.04 mm. CONCLUSION: This work enables greater accuracy to be achieved in passive fiducial tracking.
Authors: Axel Krieger; Robert C Susil; Cynthia Ménard; Jonathan A Coleman; Gabor Fichtinger; Ergin Atalar; Louis L Whitcomb Journal: IEEE Trans Biomed Eng Date: 2005-02 Impact factor: 4.538
Authors: R A Omary; O Unal; D S Koscielski; R Frayne; F R Korosec; C A Mistretta; C M Strother; T M Grist Journal: J Vasc Interv Radiol Date: 2000-09 Impact factor: 3.464
Authors: Olga Tymofiyeva; Florian Schmid; Markus von Kienlin; Felix A Breuer; Kurt Rottner; Julian Boldt; Ernst-Juergen Richter; Peter M Jakob Journal: MAGMA Date: 2010-09-29 Impact factor: 2.310
Authors: Abubakr Eldirdiri; Frédéric Courivaud; Rafael Palomar; Per Kristian Hol; Ole Jakob Elle Journal: Int J Comput Assist Radiol Surg Date: 2013-08-23 Impact factor: 2.924