Post on 08-Aug-2020
transcript
Fluoroscopic kinematography: Technical background and
potential applications
Peter Böttcher Prof. Dr. med. vet., Dipl. ECVS
www.fluokin.de
FluoKin.de
Kinematics vs. kinetics
• Kinematics = motion
• Kinetics = forces
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Common approaches in-vivo
• Force plate
Tepic 2007
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Common approaches in-vivo
• Kinematography
Clements et al. 2005
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Video based 3D-gait analysis
Dogs in Motion, Martin S. Fischer & Karin E.Lilje
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Skin movement
Dogs in Motion, Martin S. Fischer & Karin E.Lilje
FluoKin.de
Skin movement
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Skin Movement
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Non-invasive estimation of kinematics in-vivo
• Video-analysisa c
“The large soft-tissue artefacts when using clustered skin markers, irrespective of the fixation method, question the usefulness of parameters found with external movement registration and clinical interpretation of stair data in small patient groups”.
Garling et al. Journal of Biomechanics (2007)
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Why do we need more detail?• Pathologies with low range of motion
• Contact Analysis– Restoration of normal contact mechanics?
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Prof. Martin S. Fischer, Institut für Spezielle Zoologie und Evolutionsbiologie, Jena, Germany
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Complex Skeletal Animation
Dogs in Motion, Martin S. Fischer & Karin E.Lilje
FluoKin.de
Musculo-Skeletal Animation
Dogs in Motion, Martin S. Fischer & Karin E.Lilje
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Uniplanar Fluoroscopy
• 1.5 y, Rottweiler• Lameness left hind leg, knee stable on palpation
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C-Arm + Videocamera
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Uni-planar, C-Arm
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Fluoroscopic kinematography
= Shadow theatre
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Image Undistortion
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Image Calibration
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www.xromm.org
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3D Animation
With markers• Tantalum beads
0.5-1.0 mm Ø• Precision: 0.064 mm*
Without markers• 2D to 3D image registration• Tracking of anatomical
features (bone shape)• Precision: 0.77 mm#
Invasive Non invasive
*Tashman et al. 2003 *Rey et al. 2009
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3D-2D-image registration
Fluoroscopic video sequence
Digital reconstructed radiograph (DRR)
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Optimisation
Intelligent form of trial & error
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Find the optimal match
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Automatic tracking
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Final 3D Animation
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Scientific Rotoscoping
Xromm.org
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Free Software
• XROMM (Brown University)
– Marker-based– Rotoscoping– AutoScoper
• JointTrack(Florida)
FluoKin.de
Accuracy with uni-planar• Left tibia• Known translation• CT-Data (0.5 mm slice thickness)• Fluo: 576x768 (0.54mm2)
• Focal distance 90 cm
Iopollo et al. Journal of Biome-chanics (2007)
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Results
• Cranio-caudal translation
• Mean error: 0.31 mm
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DRR
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Results
• Medio-lateral translation (in-plane)
• Mean error: 4.58 mm
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DRR
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Stereo = 3D = High accuracy
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Bi-planar, high-powered X-ray
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Final 3D-Animation
Xromm.org
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Bone embedded coordinate system
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Contact Analysis
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Current Projects
• Stifle
• Elbow
• Shoulder
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Other applications
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Other applications
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Other applications
Brown University
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Other applications
Source unknown
FluoKin.de
www.fluokin.de