title: Repeatability and sensitivity of T2* measurements in patients with head and neck squamous cell carcinoma at 3T.
abstract: To determine whether quantitation of T2* is sufficiently repeatable and sensitive to detect clinically relevant oxygenation levels in head and neck squamous cell carcinoma (HNSCC) at 3T.
  
  
  
  Ten patients with newly diagnosed locally advanced HNSCC underwent two magnetic resonance imaging (MRI) scans between 24 and 168 hours apart prior to chemoradiotherapy treatment. A multiple gradient echo sequence was used to calculate T2* maps. A quadratic function was used to model the blood transverse relaxation rate as a function of blood oxygenation. A set of published coefficients measured at 3T were incorporated to account for tissue hematocrit levels and used to plot the dependence of fractional blood oxygenation (Y) on T2* values, together with the corresponding repeatability range. Repeatability of T2* using Bland-Altman analysis, and calculation of limits of agreement (LoA), was used to assess the sensitivity, defined as the minimum difference in fractional blood oxygenation that can be confidently detected.
  
  
  
  T2* LoA for 22 outlined tumor volumes were 13%. The T2* dependence of fractional blood oxygenation increases monotonically, resulting in increasing sensitivity of the method with increasing blood oxygenation. For fractional blood oxygenation values above 0.11, changes in T2* were sufficient to detect differences in blood oxygenation greater than 10% (Δ T2* > LoA for ΔY > 0.1).
  
  
  
  Quantitation of T2* at 3T can detect clinically relevant changes in tumor oxygenation within a wide range of blood volumes and oxygen tensions, including levels reported in HNSCC. J. Magn. Reson. Imaging 2016;44:72-80.
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Rafal
authors.initials: R
authors.lastname: Panek
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Liam
authors.initials: L
authors.lastname: Welsh
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Dunlop
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Kee H
authors.initials: KH
authors.lastname: Wong
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Riddell
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Dow-Mu
authors.initials: DM
authors.lastname: Koh
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Schmidt
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Doran
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Dualta
authors.initials: D
authors.lastname: Mcquaid
authors.affiliation: Royal Marsden NHS Trust, London, UK.
authors.forename: Georgina
authors.initials: G
authors.lastname: Hopkinson
authors.affiliation: Royal Marsden NHS Trust, London, UK.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Richardson
authors.affiliation: Royal Marsden NHS Trust, London, UK.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Nutting
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Shreerang A
authors.initials: SA
authors.lastname: Bhide
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Harrington
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Robinson
authors.affiliation: Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Kate L
authors.initials: KL
authors.lastname: Newbold
authors.affiliation: CR-UK Cancer Imaging Centre, London, UK.|Institute of Cancer Research, London, UK.|Royal Marsden NHS Trust, London, UK.
authors.forename: Martin O
authors.initials: MO
authors.lastname: Leach
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000378:metabolism*; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010100:Oxygen / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D014408:Biomarkers, Tumor; D010100:Oxygen
keywords: BOLD; MRI; head and neck; hypoxia; oxygen