title: Age-dependency of glycosaminoglycan content in lumbar discs: A 3t gagcEST study.
abstract: OBJECTIVE
  To analyze age-dependency of glycosaminoglycan content using gagCEST (glycosaminoglycan chemical exchange saturation transfer) imaging in lumbar intervertebral discs of healthy volunteers.
  
  
  METHODS
  In all, 70 volunteers without low back pain (mean age 44 ± 14 years, range: 21-69 years) were examined with T2 -weighted and gagCEST imaging with a 3T MR scanner, with approval of the local Ethics Committee after written informed consent was obtained. Pfirrmann grading and classification into discs without bulging and herniation, discs with bulging, and discs with herniation were performed. Only intervertebral discs without bulging and herniation were analyzed. A region-of-interest-based gagCEST analysis of nucleus pulposus (NP) and annulus fibrosus (AF) was performed. Correlation between age and gagCEST was tested within groups of equal Pfirrmann score.
  
  
  RESULTS
  GagCEST effects decreased significantly from 3.09 ± 1.12% in 20-29 years old volunteers to -0.24 ± 1.36% in 50-59 years old volunteers (P < 0.001). In the case of Pfirrmann scores 2 and 3, a significant correlation was observed between gagCEST effect and age (Pfirrmann score 2, NP: ρ = -0.558, P < 0.001; Pfirrmann score 3, NP: ρ = -0.337, P = 0.048). For Pfirrmann scores 1 and 4, no significant correlation was obtained (Pfirrmann score 1, NP: ρ = -0.046, P = 0.824; Pfirrmann score 4, NP: ρ = -0.316, P = 0.188).
  
  
  CONCLUSIONS
  We show a decreased gagCEST effect likely corresponding to decreasing glycosaminoglycans with aging. Hence, age-matched analysis of gagCEST imaging may be necessary in future studies.
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Müller-Lutz
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schleich
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Gael
authors.initials: G
authors.lastname: Pentang
authors.affiliation: Siemens Australia, Healthcare Sector, Macquarie Park NSW, Australia.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schmitt
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Rotem S
authors.initials: RS
authors.lastname: Lanzman
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Matuschke
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Wittsack
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Miese
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007403:Intervertebral Disc / Q000033:anatomy & histology / Q000378:metabolism*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D006025:Glycosaminoglycans
keywords: chemical exchange saturation transfer (CEST); glycosaminoglycans; intervertebral disc; magnetic resonance imaging (MRI)