title: MR imaging of articular cartilage in the ankle: comparison of available imaging sequences and methods of measurement in cadavers.
abstract: OBJECTIVE
  To assess hyaline cartilage of cadaveric ankles using different magnetic resonance (MR) imaging techniques and various methods of measurement.
  
  
  METHODS
  Cartilage thicknesses of the talus and tibia were measured in ten cadaveric ankles by naked eye and by digitized image analysis from MR images of fat-suppressed T1-weighted gradient recalled (FS-SPGR), sequences and pulsed transfer saturation sequences with (FS-STS) and without fat-suppression (STS); these measurements were compared with those derived from direct inspection of cadaveric sections. The accuracy and precision errors were evaluated statistically for each imaging technique as well as measuring method. Contrast-to-noise ratios of cartilage versus joint fluid and marrow were compared for each of the imaging sequences.
  
  
  RESULTS
  Statistically, measurements from FS-SPGR images were associated with the smallest estimation error. Precision error of measurements derived from digitized image analysis was found to be smaller than that derived from naked eye measurements. Cartilage thickness measurements in images from STS and FS-STS sequences revealed larger errors in both accuracy and precision. Inter-observer variance was larger in naked eye assessment of the cartilage. Contrast-to-noise ratio of cartilage versus joint fluid and marrow was higher with FS-SPGR than with FS-STS or STS sequences.
  
  
  CONCLUSIONS
  Of the sequences and measurement techniques studied, the FS-SPGR sequence combined with the use of digitized image analysis provides the most accurate method for the assessment of ankle hyaline cartilage.
authors.affiliation: Department of Radiology, Veterans Administrative Medical Center, San Diego, CA 92161, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Tan
authors.forename: D M
authors.initials: DM
authors.lastname: Wilcox
authors.forename: L
authors.initials: L
authors.lastname: Frank
authors.forename: C
authors.initials: C
authors.lastname: Shih
authors.forename: D J
authors.initials: DJ
authors.lastname: Trudell
authors.forename: D J
authors.initials: DJ
authors.lastname: Sartoris
authors.forename: D
authors.initials: D
authors.lastname: Resnick
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000033:anatomy & histology*; D016477:Artifacts; D002102:Cadaver; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*