title: Quantitative mapping of human cartilage at 3.0T: parallel changes in T₂, T₁ρ, and dGEMRIC.
abstract: OBJECTIVE
  The objectives of this study were to measure the parallel changes of transverse relaxation times (T₂), spin-lattice relaxation time in the rotating frame (T₁ρ), and the delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC)-T1 mapping of human knee cartilage in detecting cartilage degeneration at 3.0T.
  
  
  METHODS
  Healthy volunteers (n = 10, mean age 35.6 years) and patients (n = 10, mean age 65 years) with early knee osteoarthritis (OA) were scanned at 3.0T MR using an 8-channel phased array knee coil (transmit-receive). Quantitative assessment of T₂, T₁ρ, and dGEMRIC-T₁ values (global and regional) were correlated between asymptomatic subjects and patients with OA.
  
  
  RESULTS
  The average T₂ (39 ± 2 milliseconds [mean ± standard deviation] vs. 47 ± 6 milliseconds, P < .0007) and T₁ρ (48 ± 3 vs. 62 ± 8 milliseconds, P < .0002) values were all markedly increased in all patients with OA when compared to healthy volunteers. The average dGEMRIC-T₁ (1244 ± 134 vs. 643 ± 227 milliseconds, P < .000002) value was sharply decreased after intravenous administration of gadolinium contrast agent in all patients with OA.
  
  
  CONCLUSIONS
  The research results showed that all the T₂, T₁ρ, and dGEMRIC-T₁ relaxation times varied with the cartilage degeneration. The dGEMRIC-T₁ and T₁ρ relaxation times seem to be more sensitive than T₂ in detecting early cartilage degeneration. The preliminary study demonstrated that the early biochemical changes in knee osteoarthritic patients could be detected noninvasively in in vivo using T₁ρ and dGEMRIC-T₁ mapping.
authors.affiliation: Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016, USA; School of Radiation Medicine and Protection, Medical College of Soochow University, Rm. 2206, Building 402, 199 Ren Ai Rd, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, China; School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Rm. 2206, Building 402, 199 Ren Ai Rd, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, China. Electronic address: bastion@163.com.
authors.forename: Ligong
authors.initials: L
authors.lastname: Wang
authors.affiliation: Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016, USA.
authors.forename: Ravinder R
authors.initials: RR
authors.lastname: Regatte
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002357:Cartilage Diseases / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: T(1ρ); T(2); cartilage imaging; dGEMRIC; osteoarthritis