title: T1ρ mapping of pediatric epiphyseal and articular cartilage in the knee.
abstract: OBJECTIVE
  To evaluate the feasibility of measuring T1ρ values in epiphyseal cartilage in children, we have conducted a novel study of spin locking techniques. Adult articular cartilage has been widely studied with spin locking techniques by magnetic resonance imaging. However, no results are available for in vivo T1ρ imaging of developing cartilage.
  
  
  METHODS
  Ten volunteers of age 6 ± 3 years were recruited to have T1ρ mapping performed on the knee at the conclusion of their clinical study. T1ρ maps were generated using a spin-lock cluster followed by a fast spin-echo imaging sequence. Regions of interest (ROIs) were placed in non-load-bearing (NLB), load-bearing (LB), and articular cartilage.
  
  
  RESULTS
  Student's t-tests were performed to compare means among the ROIs. Mean T1ρ for epiphyseal and articular cartilage was 49.8 ± 9 and 76.6 ± 7 ms, respectively. LB and NLB T1ρ vales were 47.1 ± 9.5 and 52.5 ± 9 ms, respectively. Significant differences were found in T1ρ values between epiphyseal and articular cartilage layers (P = 0.0001). No difference in T1ρ was observed between NLB and LB layers. A modest trend was also noted for epiphyseal and articular cartilage regions with age.
  
  
  CONCLUSIONS
  It is feasible to quantify differences in epiphyseal and articular cartilage layers with SL techniques. T1ρ holds promise as a noninvasive method of studying normal and abnormal developmental states of cartilage in children.
authors: Vanderbilt University Department of Biomedical Engineering, Nashville, Tennessee, USA. jared.g.cobb@vanderbilt.edu
authors: Jared Guthrie
authors: JG
authors: Cobb
authors: J Herman
authors: JH
authors: Kan
authors: John C
authors: JC
authors: Gore
mesh_terms: D000465:Algorithms; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D002648:Child; D005240:Feasibility Studies; D005260:Female; D006132:Growth Plate / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: 3T; T1ρ; cartilage; spin lock
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