title: Longitudinal assessment of bone marrow edema-like lesions and cartilage degeneration in osteoarthritis using 3 T MR T1rho quantification.
abstract: OBJECTIVE
  To quantitatively assess the relationship between bone marrow edema-like lesions (BMELs) and the associated cartilage in knee osteoarthritis (OA) using T(1rho) quantification at 3 T MRI.
  
  
  METHODS
  Twenty-four patients with knee OA and 14 control subjects underwent 3 T MRI. Nineteen patients and all control subjects had 1-year follow-up studies. The volume and signal intensity difference of BMELs were calculated. Cartilage degeneration was graded using the cartilage subscore of Whole-Organ MRI Score (WORMS) analysis. Cartilage T(1rho) values were calculated in each compartment as well as in cartilage overlying BMELs (OC) and surrounding cartilage (SC).
  
  
  RESULTS
  At baseline, 25 BMELs were found in 16 out of 24 patients. The overall T(1rho) values were significantly higher in patients with BMELs than in those without BMELs. At baseline and follow-up, both T(1rho) values and WORMS cartilage subscore grading were significantly higher in OC than SC. Cartilage T(1rho) increase from baseline to follow-up in OC was significantly higher than that in SC. An increase in T(1rho) values in OC was correlated with signal intensity of BMEL at both baseline and follow-up, but was not correlated with BMEL volume.
  
  
  CONCLUSIONS
  The results of this study suggest a local spatial correlation between BMELs and more advanced and accelerated cartilage degeneration. MRI T(1rho) quantification in cartilage provides a sensitive tool for evaluating such correlations.
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94107, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhao
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.forename: Radu I
authors.initials: RI
authors.lastname: Bolbos
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D001855:Bone Marrow Diseases / Q000175:diagnosis* / Q000209:etiology; D002357:Cartilage Diseases / Q000175:diagnosis* / Q000209:etiology; D004487:Edema / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000175:diagnosis*