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Method for automatic localization of MR‐visible markers using morphological image processing and conventional pulse sequences: Feasibility for image‐guided procedures
Author(s) -
Busse Harald,
Trampel Robert,
Gründer Wilfried,
Moche Michael,
Kahn Thomas
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21129
Subject(s) - fiducial marker , isocenter , scanner , orientation (vector space) , image processing , artificial intelligence , physics , optics , nuclear medicine , computer science , computer vision , biomedical engineering , image (mathematics) , medicine , mathematics , imaging phantom , geometry
Purpose To evaluate the feasibility and accuracy of an automated method to determine the 3D position of MR‐visible markers. Materials and Methods Inductively coupled RF coils were imaged in a whole‐body 1.5T scanner using the body coil and two conventional gradient echo sequences (FLASH and TrueFISP) and large imaging volumes up to (300 mm 3 ). To minimize background signals, a flip angle of ≈1° was used. Morphological 2D image processing in orthogonal scan planes was used to determine the 3D positions of a configuration of three fiducial markers (FMC). The accuracies of the marker positions and of the orientation of the plane defined by the FMC were evaluated at various distances r M from the isocenter. Results Fiducial marker detection with conventional equipment (pulse sequences, imaging coils) was very reliable and highly reproducible over a wide range of experimental conditions. For r M ≤ 100 mm, the estimated maximum errors in 3D position and angular orientation were 1.7 mm and 0.33°, respectively. For r M ≤ 175 mm, the respective values were 2.9 mm and 0.44°. Conclusions Detection and localization of MR‐visible markers by morphological image processing is feasible, simple, and very accurate. In combination with safe wireless markers, the method is found to be useful for image‐guided procedures. J. Magn. Reson. Imaging 2007;26:1087–1096. © 2007 Wiley‐Liss, Inc.