title: In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC).
abstract: BACKGROUND
  Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-.
  
  
  METHODS
  The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3 mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1 = 1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180 minutes after injection, and the change in relaxation rate (ΔR1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation.
  
  
  RESULTS
  The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ΔR1 were similar for double and triple doses of the contrast agent. ΔR1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ΔR1 increased until 90-180 minutes in both the cartilage and the meniscus (p < 0.05), and was lower in the medial than in the lateral meniscus at all time points (p < 0.05). A faster increase in ΔR1 was observed in the vascularized peripheral region of the posterior medial meniscus, than in the avascular central part of the posterior medial meniscus during the first 60 minutes (p < 0.05).
  
  
  CONCLUSIONS
  It is feasible to examine undamaged meniscus and cartilage simultaneously using dGEMRIC, preferably 90 minutes after the injection of a double dose of Gd-DTPA2- (0.2 mmol/kg body weight).
authors.affiliation: Department of Orthopaedics, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden. ulf.sigurdsson@skane.se.
authors.forename: Ulf
authors.initials: U
authors.lastname: Sigurdsson
authors.forename: Carl
authors.initials: C
authors.lastname: Siversson
authors.forename: Eveliina
authors.initials: E
authors.lastname: Lammentausta
authors.forename: Jonas
authors.initials: J
authors.lastname: Svensson
authors.forename: Carl-Johan
authors.initials: CJ
authors.lastname: Tiderius
authors.forename: Leif E
authors.initials: LE
authors.lastname: Dahlberg
mesh_terms: D000328:Adult; D003287:Contrast Media / Q000008:administration & dosage / Q000378:metabolism*; D005240:Feasibility Studies; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000378:metabolism*; D064368:Healthy Volunteers; D006801:Humans; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000033:anatomy & histology* / Q000378:metabolism*; D011237:Predictive Value of Tests; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA