dGEMRIC (delayed gadolinium-enhanced MRI of cartilage) indicates adaptive capacity of human knee cartilage.
Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a new imaging technique to estimate joint cartilage glycosaminoglycan content by T1-relaxation time measurements after penetration of the hydrophilic contrast agent Gd-DTPA(2-). This study compares dGEMRIC in age-matched healthy volunteers with different levels of physical activity: Group 1 (n = 12): nonexercising individuals; Group 2 (n = 16): individuals with physical exercise averaging twice weekly; Group 3 (n = 9): male elite runners. dGEMRIC was performed 2 hr after an intravenous injection of Gd-DTPA(2-) at 0.3 mmol/kg body weight. T1 differed significantly between the three different levels of physical exercise. T1 values (mean of medial and lateral femoral cartilage) for Groups 1, 2, and 3 were: 382 +/- 33, 424 +/- 22 and 476 +/- 36, respectively (ms, mean +/- SD) (P = 0.0004, 1 vs. 2 and 0.0002, 2 vs. 3). Irrespective of the exercise level, T1 was longer in lateral compared to medial femoral cartilage (P = 0.00005; n = 37). In conclusion, this cross-sectional study indicates that human knee cartilage adapts to exercise by increasing the glycosaminoglycan content. Furthermore, results suggest a compartmental difference within the knee with a higher glycosaminoglycan content in lateral compared to medial femoral cartilage. A higher proportion of extracellular water, i.e., larger distribution volume, may to some extent explain the high T1 in the elite runners.
Tiderius
Carl Johan
CJ
Department of Orthopedics, Malmö University Hospital, Lund University, Malmö, Sweden.
Svensson
Jonas
J
Leander
Peter
P
Ola
Thorsson
T
Dahlberg
Leif
L
D000328:Adult; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000378:metabolism / Q000502:physiology*; D003287:Contrast Media; D015444:Exercise / Q000502:physiology*; D005260:Female; D019786:Gadolinium DTPA; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
D003287:Contrast Media; D006025:Glycosaminoglycans; D019786:Gadolinium DTPA