title: Initial results of in vivo high-resolution morphological and biochemical cartilage imaging of patients after matrix-associated autologous chondrocyte transplantation (MACT) of the ankle.
abstract: OBJECTIVE
  The aim of this study was to use morphological as well as biochemical (T2 and T2* relaxation times and diffusion-weighted imaging (DWI)) magnetic resonance imaging (MRI) for the evaluation of healthy cartilage and cartilage repair tissue after matrix-associated autologous chondrocyte transplantation (MACT) of the ankle joint.
  
  
  METHODS
  Ten healthy volunteers (mean age, 32.4 years) and 12 patients who underwent MACT of the ankle joint (mean age, 32.8 years) were included. In order to evaluate possible maturation effects, patients were separated into short-term (6-13 months) and long-term (20-54 months) follow-up cohorts. MRI was performed on a 3.0-T magnetic resonance (MR) scanner using a new dedicated eight-channel foot-and-ankle coil. Using high-resolution morphological MRI, the magnetic resonance observation of cartilage repair tissue (MOCART) score was assessed. For biochemical MRI, T2 mapping, T2* mapping, and DWI were obtained. Region-of-interest analysis was performed within native cartilage of the volunteers and control cartilage as well as cartilage repair tissue in the patients subsequent to MACT.
  
  
  RESULTS
  The overall MOCART score in patients after MACT was 73.8. T2 relaxation times (approximately 50 ms), T2* relaxation times (approximately 16 ms), and the diffusion constant for DWI (approximately 1.3) were comparable for the healthy volunteers and the control cartilage in the patients after MACT. The cartilage repair tissue showed no significant difference in T2 and T2* relaxation times (p > or = 0.05) compared to the control cartilage; however, a significantly higher diffusivity (approximately 1.5; p < 0.05) was noted in the cartilage repair tissue.
  
  
  CONCLUSIONS
  The obtained results suggest that besides morphological MRI and biochemical MR techniques, such as T2 and T2* mapping, DWI may also deliver additional information about the ultrastructure of cartilage and cartilage repair tissue in the ankle joint using high-field MRI, a dedicated multichannel coil, and sophisticated sequences.
authors.affiliation: MR Center--High-Field MR, Department of Radiology, Medical University of Vienna, Vienna General Hospital, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Quirbach
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
authors.forename: Stefan
authors.initials: S
authors.lastname: Marlovits
authors.forename: Valentin
authors.initials: V
authors.lastname: Zimmermann
authors.forename: Stephan
authors.initials: S
authors.lastname: Domayer
authors.forename: Ronald
authors.initials: R
authors.lastname: Dorotka
authors.forename: Tallal C
authors.initials: TC
authors.lastname: Mamisch
authors.forename: Klaus
authors.initials: K
authors.lastname: Bohndorf
authors.forename: Goetz H
authors.initials: GH
authors.lastname: Welsch
mesh_terms: D000328:Adult; D016512:Ankle Injuries / Q000473:pathology* / Q000601:surgery*; D019902:Chondrocytes / Q000473:pathology / Q000637:transplantation*; D005260:Female; D050724:Fractures, Cartilage / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010865:Pilot Projects; D011379:Prognosis; D054457:Tissue Scaffolds; D016896:Treatment Outcome