title: Knee cartilage MRI with in situ mechanical loading using prospective motion correction.
abstract: OBJECTIVE
  To assess the feasibility of high resolution knee cartilage MRI with in situ mechanical loading using optical tracking to compensate for motion.
  
  
  METHODS
  In vivo cartilage MRI with in situ mechanical loading is demonstrated on a clinical 3T system for the patellofemoral as well as for the tibiofemoral knee joint using a T1-weighted spoiled three-dimensional gradient-echo sequence. Prospective motion correction is performed with a moiré phase tracking system consisting of an in-bore camera and a single tracking marker attached to the skin.
  
  
  RESULTS
  Rigid-body approximation required for prospective correction with optical motion tracking is fulfilled well enough for the patellofemoral as well as for the tibiofemoral joint when the tracking marker is attached to the knee cap and the shin, respectively. Presaturation proves to be efficient in suppressing pulsation artifacts from the popliteal artery and residual motion artifacts primarily arising from nonrigid motion of the posterior knee compartment.
  
  
  CONCLUSIONS
  The proposed technique enables knee cartilage imaging under in situ mechanical loading with submillimeter spatial resolution devoid of significant motion artifacts and thus appropriate for cartilage volumetry. It has the potential to provide new insight into the biomechanics of the knee and might complement the panoply of diagnostic MR methods for osteoarthritis.
authors: Department of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany.
authors: Thomas
authors: T
authors: Lange
authors: Julian
authors: J
authors: Maclaren
authors: Michael
authors: M
authors: Herbst
authors: Cris
authors: C
authors: Lovell-Smith
authors: Kaywan
authors: K
authors: Izadpanah
authors: Maxim
authors: M
authors: Zaitsev
mesh_terms: D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology*; D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint; D008279:Magnetic Resonance Imaging / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000473:pathology