title: Sodium MR imaging of the lumbar intervertebral disk at 7 T: correlation with T2 mapping and modified Pfirrmann score at 3 T--preliminary results.
abstract: OBJECTIVE
  To compare sodium imaging of lumbar intervertebral disks in asymptomatic volunteers at 7-T magnetic resonance (MR) imaging with quantitative T2 mapping and morphologic scoring at 3 T.
  
  
  METHODS
  Following ethical board approval and informed consent, the L2-3 to L5-S1 disks were examined in 10 asymptomatic volunteers (nine men, one woman; mean age, 30 years; range, 23-43 years). At 7 T, normalized sodium signal-to-noise ratios were calculated, by using region-of-interest analysis. At 3 T, T2 mapping was performed with a multiecho spin-echo sequence (repetition time msec/echo times msec, 1500/24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156). T2 values were calculated over the nucleus, with a pixelwise, monoexponential nonnegative least-squares-fit analysis. Morphologic grading according to a modified Pfirrmann score was assessed independently by three experienced musculoskeletal radiologists, and Pearson correlation analysis of the covariates was performed.
  
  
  RESULTS
  The mean normalized sodium signal intensity was 275.5±115.4 (standard deviation). The T2 mapping showed a mean value of 89.8 msec±19.34. The median modified Pfirrmann score was 2b (90% had score≤3c). The Pearson correlation coefficient showed a cubic function between sodium imaging and the modified Pfirrmann score, a moderate inverse correlation between T2 mapping and the modified Pfirrmann score (r=-0.62), and no correlation between sodium imaging and T2 mapping (r=0.06).
  
  
  CONCLUSIONS
  The results suggest that MR imaging of the intervertebral disk, using sodium imaging and T2 mapping, can help characterize different component changes and that both of these methods are to some degree related to the Pfirrmann score.
authors.affiliation: MR Centre-High Field MR, Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University of Vienna/Vienna General Hospital, Waerhringer Guertel 18-20, A-1090 Vienna, Austria. iris.noebauer@meduniwien.ac.at
authors.forename: Iris-Melanie
authors.initials: IM
authors.lastname: Noebauer-Huhmann
authors.forename: Vladimir
authors.initials: V
authors.lastname: Juras
authors.forename: Christian W A
authors.initials: CW
authors.lastname: Pfirrmann
authors.forename: Pavol
authors.initials: P
authors.lastname: Szomolanyi
authors.forename: Stefan
authors.initials: S
authors.lastname: Zbyn
authors.forename: Alina
authors.initials: A
authors.lastname: Messner
authors.forename: Johannes
authors.initials: J
authors.lastname: Wimmer
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Klaus M
authors.initials: KM
authors.lastname: Friedrich
authors.forename: David
authors.initials: D
authors.lastname: Stelzeneder
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007403:Intervertebral Disc / Q000033:anatomy & histology*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D055815:Young Adult