title: MR spectroscopy measurement of the diffusion of dimethyl sulfoxide in articular cartilage and comparison to theoretical predictions.
abstract: Cartilage cryopreservation requires optimal loading of protective solutes, most commonly dimethyl sulfoxide (DMSO), to maximize chondrocyte survival. Previously, diffusion models have been used to predict the distribution of solutes in tissue samples, but the accuracy of spatiotemporal predictions of these models have not been validated with empirical studies and remains unknown.
  
  
  OBJECTIVE
  In this study, magnetic resonance spectroscopic imaging was used to measure the spatial and temporal changes in DMSO and water concentrations in porcine articular cartilage plugs, throughout 1 h of solute loading.
  
  
  METHODS
  A custom NMR spectroscopic imaging pulse sequence provided water and DMSO concentration images with an in-plane spatial resolution of 135 μm and a temporal resolution of 150 s, repeated for 60 min throughout DMSO loading. Delayed gadolinium-enhanced magnetic resonance of cartilage (d-GEMRIC) imaging provided fixed charge density and spin-density imaging provided water density images prior to DMSO loading.
  
  
  RESULTS
  The measured spatial and temporal distribution of DMSO in three different samples was compared to independent predictions of Fick's law and the modified triphasic biomechanical model by Abazari et al. (2011) with the empirical data more closely agreeing with the triphasic model.
  
  
  CONCLUSIONS
  Dynamic NMR spectroscopic imaging can measure spatial and temporal changes in water and cryoprotectant concentrations in articular cartilage. The modified triphasic model predictions for the interstitial distribution of DMSO were confirmed and its advantage over the predictions by Fick's law model, which is commonly used in the literature of cryobiology, was demonstrated.
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2V4, Canada. aa1@ualberta.ca
authors.forename: A
authors.initials: A
authors.lastname: Abazari
authors.forename: J A W
authors.initials: JA
authors.lastname: Elliott
authors.forename: L E
authors.initials: LE
authors.lastname: McGann
authors.forename: R B
authors.initials: RB
authors.lastname: Thompson
mesh_terms: D000465:Algorithms; D000818:Animals; D002358:Cartilage, Articular / Q000737:chemistry*; D015925:Cryopreservation / Q000379:methods; D003451:Cryoprotective Agents / Q000032:analysis*; D004121:Dimethyl Sulfoxide / Q000032:analysis*; D005682:Gadolinium; D006614:Hindlimb / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008962:Models, Theoretical; D013552:Swine; D014867:Water / Q000032:analysis*
chemical_list: D003451:Cryoprotective Agents; D014867:Water; D005682:Gadolinium; D004121:Dimethyl Sulfoxide