title: Assessment of colorectal liver metastases using MRI and CT: impact of observer experience on diagnostic performance and inter-observer reproducibility with histopathological correlation.
abstract: BACKGROUND
  To compare the diagnostic performance and inter-observer reproducibility of CT and MRI in detecting colorectal liver metastases (CRLM) of observers with different levels of experience.
  
  
  METHODS
  Data from 51 CT and 54 MRI examinations of 105 patients with CRLM were analysed. Intraoperative and histopathological findings served as the reference standard. Analyses were performed by four observers with varying levels of experience regarding imaging of CRLM (reviewers A, B, C and D with respectively >20, >5, <1 and 0 years of experience). Per-segment sensitivity, specificity, Cohen's kappa (κ) for diagnosed segments and Intra-class Correlation Coefficients (ICC) for reported number of lesions were calculated.
  
  
  RESULTS
  CT sensitivity and specificity was for reviewer A 89.71%/94.41%, B 78.50%/88.37%, C 63.55%/85.58%, D 84.11%/78.60% and regarding MRI A 90.40%/95.43%, B 74.40%/90.04%, C 60.00%/85.89% and D 65.60%/75.90%. The overall inter-observer agreement was higher for CT (κ=0.43, p<0.001; ICC=0.75, p<0.001) than MRI (κ=0.38, p<0.001; ICC=0.65, p<0.001). The experienced reviewers A and B achieved better agreement for MRI (κ=0.54, p<0.001; ICC=0.77, p<0.001) than CT (κ=0.52, p<0.00; ICC=0.76, p<0.001) unlike the less experienced C and D (MRI κ=0.38, ICC=0.63 and CT κ=0.41, ICC=0.74, respectively, p<0.001).
  
  
  CONCLUSIONS
  The proficiency in detection of CRLM is significantly influenced by observer experience, although CT interpretation is less affected than MRI analysis.
authors.affiliation: University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany. Electronic address: MoritzAlbrecht@gmx.net.
authors.forename: Moritz H
authors.initials: MH
authors.lastname: Albrecht
authors.affiliation: University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Julian L
authors.initials: JL
authors.lastname: Wichmann
authors.affiliation: University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Cindy
authors.initials: C
authors.lastname: Müller
authors.affiliation: University Hospital Frankfurt, Department of General and Visceral Surgery, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Theresa
authors.initials: T
authors.lastname: Schreckenbach
authors.affiliation: Barts and the London, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.
authors.forename: Sreekanth
authors.initials: S
authors.lastname: Sakthibalan
authors.affiliation: University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Renate
authors.initials: R
authors.lastname: Hammerstingl
authors.affiliation: University Hospital Frankfurt, Department of General and Visceral Surgery, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Wolf O
authors.initials: WO
authors.lastname: Bechstein
authors.affiliation: University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Zangos
authors.affiliation: University Hospital Frankfurt, Department of Biostatistics and Medical Information, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Hanns
authors.initials: H
authors.lastname: Ackermann
authors.affiliation: University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Vogl
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006498:Hepatectomy; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: CT; Diagnostic performance; Experience; Liver imaging; MRI