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 approximately 1 degrees 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 degrees , respectively. For r(M) </= 175 mm, the respective values were 2.9 mm and 0.44 degrees . 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. (c) 2007 Wiley-Liss, Inc.
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 approximately 1 degrees 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 degrees , respectively. For r(M) </= 175 mm, the respective values were 2.9 mm and 0.44 degrees . 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. (c) 2007 Wiley-Liss, Inc.
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
Authors: Jens Ricke; Markus Thormann; Matthias Ludewig; Kerstin Jungnickel; Oliver Grosser; Christian Wybranski; Nils Peters; Peter Hass; Jürgen Bunke; Frank Fischbach Journal: Eur Radiol Date: 2010-03-20 Impact factor: 5.315