title: T2relaxation mapping MRI of healthy and inflamed gingival tissue.
abstract: OBJECTIVE
  To investigate the use and reproducibility of MRI transverse relaxation time (T2) mapping in healthy and inflamed gingivae.
  
  
  METHODS
  21 subjects were recruited into 2 groups: those without evidence of gingivitis ("healthy"; n = 11, age 24.0 ± 3.66 years) by visual assessment and those with moderate to severe gingivitis ("gingivitis"; n = 10, age 28.9 ± 6.03 years) exhibited across the second mandibular premolar and first mandibular molar buccal gingivae. Subjects were imaged by MRI twice in a single day. Three T2weighted turbo spin-echo volumes with 0.25 × 0.25 × 0.8-mm3resolution were acquired at echo times of 16, 32 and 48 ms for T2decay fitting. Image analysis was fully blinded; the two imaging sessions were not identifiable as coming from the same subject. Each imaging session had independent regions of interest drawn on the first echo image and applied to the calculated T2decay maps.
  
  
  RESULTS
  The coefficient of variation was low and similar in healthy and gingivitis populations: 6.10 and 5.25% populations, respectively, with 5.65% populations across both groups. Bland-Altman analysis revealed no bias (mean -2.93%; 95% confidence intervals -22.20 to 16.34%) between sessions. The intersession agreement was good (r = 0.744, ρ = 0.568, intraclass correlation coefficient = 0.68). T2mapping did not differentiate healthy from gingivitis groups. The mean T2value in the healthy group (63.7 ms) was similar to that of the gingivitis group (65.23 ms) (p = 0.30).
  
  
  CONCLUSIONS
  Mapping of the T2decay in the gingivae was a repeatable process; however, T2value alone did not differentiate those with clinical examination-determined gingivitis from those without signs of gingivitis.
authors.affiliation: 1 Imanova Centre for Imaging Sciences, London, UK.
authors.forename: Rexford D
authors.identifier: http://orcid.org/0000-0002-2855-7973
authors.initials: RD
authors.lastname: Newbould
authors.affiliation: 1 Imanova Centre for Imaging Sciences, London, UK.
authors.forename: Courtney A
authors.initials: CA
authors.lastname: Bishop
authors.affiliation: 2 GSK, Brentford, UK.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Janiczek
authors.affiliation: 3 GSK Consumer Healthcare, Weybridge, UK.
authors.forename: Charles
authors.initials: C
authors.lastname: Parkinson
authors.affiliation: 4 Dental Institute, King's College London, London, UK.
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Hughes
mesh_terms: D000293:Adolescent; D000328:Adult; D005891:Gingivitis / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D015203:Reproducibility of Results; D055815:Young Adult
keywords: MRI; gingiva; gingivitis; inflammation