title: T1ρ magnetic resonance imaging quantification of early lumbar intervertebral disc degeneration in healthy young adults.
abstract: METHODS
  Cross-sectional study using T1ρ magnetic resonance imaging (MRI) of lumbar spine in healthy young adults.
  
  
  OBJECTIVE
  To evaluate early intervertebral disc degeneration (IDD) quantified by T1ρ- and T2-weighted MRI in asymptomatic young adults and to correlate T1ρ value with Pfirrmann degenerative grade, sex, and body mass index (BMI).
  
  
  BACKGROUND
  Intervertebral disc starts early to degenerate losing proteoglycan content in the nucleus pulposus (NP). A potential tool for the study of early stage of IDD is T1ρ MRI. T1ρ relaxation time of human discs has been correlated to proteoglycan content in previous studies.
  
  
  METHODS
  T1ρ- and T2-weighted images of the lumbar spine were obtained for 63 asymptomatic young subjects (34 men and 29 women; mean age, 22.95 ± 1.8 yr), with a 1.5-T MRI scanner. T1ρ mapping and values in the NP and anulus fibrosus (n = 315) were obtained. Degenerative grade was assessed using T2-weighted images, according to the Pfirrmann scale. Differences in T1ρ value between sexes, BMI, and linear regression analyses with degenerative grade were determined.
  
  
  RESULTS
  T1ρ values of NPs were significantly higher than those of anulus fibrosus at all levels. T1ρ values were significantly lower in women at L3-L4 and L4-L5 discs (P < 0.05). T1ρ values decreased linearly with degenerative grade. However, nondegenerated discs (Pfirrmann grades 1 and 2) showed a wide range of T1ρ relaxation time. No significant correlation was observed between T1ρ value and BMI.
  
  
  CONCLUSIONS
  The data of this study showed a significant difference in IDD onset between sexes. T1ρ values correlate with Pfirrmann degenerative grade in young adults. However, the wide distribution of T1ρ values in healthy intervertebral disc highlights the low sensitivity of Pfirrmann grade to detect the early IDD changes. T1ρ can be potentially used as a clinical tool to identify early IDD and to create a reliable quantitative scale.
authors.affiliation: Department of Radiology, Campus Bio-Medico University Hospital of Rome, Italy.
authors.forename: Bruno Beomonte
authors.initials: BB
authors.lastname: Zobel
authors.forename: Gianluca
authors.initials: G
authors.lastname: Vadalà
authors.forename: Riccardo
authors.initials: R
authors.lastname: Del Vescovo
authors.forename: Sofia
authors.initials: S
authors.lastname: Battisti
authors.forename: Francesca Maria
authors.initials: FM
authors.lastname: Martina
authors.forename: Luigi
authors.initials: L
authors.lastname: Stellato
authors.forename: Emanuele
authors.initials: E
authors.lastname: Leoncini
authors.forename: Arijitt
authors.initials: A
authors.lastname: Borthakur
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Denaro
mesh_terms: D015992:Body Mass Index; D003430:Cross-Sectional Studies; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis*; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult