title: Quantification of intrapancreatic fat in type 2 diabetes by MRI.
abstract: OBJECTIVE
  Accumulation of intrapancreatic fat may be important in type 2 diabetes, but widely varying data have been reported. The standard quantification by MRI in vivo is time consuming and dependent upon a high level of experience. We aimed to develop a new method which would minimise inter-observer variation and to compare this against previously published datasets.
  
  
  METHODS
  A technique of 'biopsying' the image to minimise inclusion of non-parenchymal tissues was developed. Additionally, thresholding was applied to exclude both pancreatic ducts and intrusions of visceral fat, with pixels of fat values of <1% or >20% being excluded. The new MR image 'biopsy' (MR-opsy) was compared to the standard method by 6 independent observers with wide experience of image analysis but no experience of pancreas imaging. The effect of the new method was examined on datasets from two studies of weight loss in type 2 diabetes.
  
  
  RESULTS
  At low levels of intrapancreatic fat neither the result nor the inter-observer CV was changed by MR-opsy, thresholding or a combination of the methods. However, at higher levels the conventional method exhibited poor inter-observer agreement (coefficient of variation 26.9%) and the new combined method improved the CV to 4.3% (p<0.03). Using either MR-opsy alone or with thresholding, the new methods indicated a closer relationship between decrease in intrapancreatic fat and fall in blood glucose.
  
  
  CONCLUSIONS
  The inter-observer variation for quantifying intrapancreatic fat was substantially improved by the new method when pancreas fat levels were moderately high. The method will improve comparability of pancreas fat measurement between research groups.
authors.affiliation: Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Ahmad
authors.identifier: http://orcid.org/0000-0003-3689-1266
authors.initials: A
authors.lastname: Al-Mrabeh
authors.affiliation: Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Kieren G
authors.initials: KG
authors.lastname: Hollingsworth
authors.affiliation: Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Steven
authors.affiliation: Department of Cellular Pathology, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals and Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Dina
authors.initials: D
authors.lastname: Tiniakos
authors.affiliation: Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Roy
authors.initials: R
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging* / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010179:Pancreas / Q000000981:diagnostic imaging* / Q000502:physiology; D000072356:Parenchymal Tissue / Q000000981:diagnostic imaging* / Q000502:physiology; D015203:Reproducibility of Results; D055815:Young Adult