title: A device guidance method for organ motion compensation in MRI-guided therapy.
abstract: Organ motion compensation in image-guided therapy is an active area of research. However, there has been little research on motion tracking and compensation in magnetic resonance imaging (MRI)-guided therapy. In this paper, we present a method to track a moving organ in MRI and control an active mechanical device for motion compensation. The method proposed is based on MRI navigator echo tracking enhanced by Kalman filtering for noise robustness. We also developed an extrapolation scheme to resolve any discrepancies between tracking and device control sampling rates. The algorithm was tested in a simulation study using a phantom and an active mechanical tool holder. We found that the method is feasible to use in a clinical MRI scanner with sufficient accuracy (0.36 mm to 1.51 mm depending on the range of phantom motion) and is robust to noise. The method proposed may be useful in MRI-guided targeted therapy, such as focused ultrasound therapy for a moving organ.
authors.affiliation: Institute for Process Control and Robotics, University of Karlsruhe, Kaiserstrasse 12, 76128 Karlsruhe, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Lesniak
authors.forename: Junichi
authors.initials: J
authors.lastname: Tokuda
authors.forename: Ron
authors.initials: R
authors.lastname: Kikinis
authors.forename: Catherina
authors.initials: C
authors.lastname: Burghart
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hata
mesh_terms: D000465:Algorithms; D001706:Biopsy; D003198:Computer Simulation; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology; D008168:Lung / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009068:Movement; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013997:Time Factors; D014463:Ultrasonography / Q000379:methods