title: Semiquantitative assessment of focal cartilage damage at 3T MRI: a comparative study of dual echo at steady state (DESS) and intermediate-weighted (IW) fat suppressed fast spin echo sequences.
abstract: OBJECTIVE
  The aim of the study was to compare semiquantitative assessment of focal cartilage damage using the dual echo at steady state (DESS)- and intermediate-weighted (IW) fat suppressed (fs) sequences at 3T MRI.
  
  
  METHODS
  Included were 201 subjects aged 35-65 with frequent knee pain. MRI was performed with the same sequence protocol as in the Osteoarthritis Initiative (OAI): sagittal IW fs, triplanar DESS and coronal IW sequences. Cartilage status was scored according to the WORMS system using all five sequences. A total of 243 focal defects were detected. In an additional consensus reading, the lesions were evaluated side-by-side using only the sagittal DESS and IW fs sequences. Lesion conspicuity was graded from 0 to 3, intrachondral signal changes adjacent to the defect were recorded and the sequence that depicted the lesion with larger diameter was noted. Wilcoxon signed-rank tests, controlled for clustering by person, were used to examine differences between the sequences.
  
  
  RESULTS
  37 (17.5%) of the scorable lesions were located in the medial tibio-femoral (TF), 48 (22.7%) in the lateral TF and 126 (59.7%) in the patello-femoral compartment. 82.5% were superficial and 17.5% full-thickness defects. Conspicuity was superior for the IW sequence (p<0.001). The DESS sequence showed more associated intrachondral signal changes (p<0.001). In 103 (48.8%) cases, the IW fs sequence depicted the lesions as being larger (p<0.001).
  
  
  CONCLUSIONS
  The IW fs sequence detected more and larger focal cartilage defects than the DESS. More intrachondral signal changes were observed with the DESS.
authors.affiliation: Quantitative Imaging Center (QIC), Department of Radiology, Boston University Medical Center, Boston, MA 02118, USA. froemer@bu.edu
authors.forename: Frank W
authors.initials: FW
authors.lastname: Roemer
authors.forename: C Kent
authors.initials: CK
authors.lastname: Kwoh
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hannon
authors.forename: Michel D
authors.initials: MD
authors.lastname: Crema
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Moore
authors.forename: John M
authors.initials: JM
authors.lastname: Jakicic
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Green
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D010147:Pain Measurement; D011446:Prospective Studies; D018709:Statistics, Nonparametric