title: Effect of physical exercise on cartilage volume and thickness in vivo: MR imaging study.
abstract: OBJECTIVE
  To quantify, with magnetic resonance (MR) imaging, the in vivo changes in cartilage volume and thickness after physical exercise.
  
  
  METHODS
  The patellae of eight volunteers were imaged six times at physical test by using a spoiled fat-suppressed gradient-echo sequence with an acquisition time of 4.10 minutes. The volunteers then performed 50 knee bends, and two more data sets were acquired 3-7 minutes and 8-12 minutes after exercise. The patellar cartilage volume was determined after three-dimensional reconstruction, and the thickness was assessed with a three-dimensional minimal-distance algorithm.
  
  
  RESULTS
  Whereas repositioning had a small effect on the measurements (mean coefficient of variation, 1.4%), a statistically significant decrease in cartilage volume was observed 3-7 minutes (mean decrease, 6.0%; P < .05) and 8-12 minutes (mean decrease, 5.2%; P < .05) after exercise. The deformation was homogeneous throughout the joint surface. In one asymptomatic volunteer, a cartilage lesion became more pronounced after exercise.
  
  
  CONCLUSIONS
  MR imaging can be used to investigate the response of articular cartilage to physical exercise in vivo. Patients or volunteers should be allowed a sufficient period of physical rest if quantitative measurements of cartilage volume and thickness are to be undertaken in longitudinal studies.
authors.affiliation: Institute for Diagnostic Radiology, Klinikum Grosshadern, Munich, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Eckstein
authors.forename: M
authors.initials: M
authors.lastname: Tieschky
authors.forename: S C
authors.initials: SC
authors.lastname: Faber
authors.forename: M
authors.initials: M
authors.lastname: Haubner
authors.forename: H
authors.initials: H
authors.lastname: Kolem
authors.forename: K H
authors.initials: KH
authors.lastname: Englmeier
authors.forename: M
authors.initials: M
authors.lastname: Reiser
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D015444:Exercise; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007719:Knee Joint; D008279:Magnetic Resonance Imaging; D008297:Male; D010329:Patella / Q000033:anatomy & histology