Interobserver Variability in Histologic Evaluation of Liver Fibrosis Using Categorical and Quantitative Scores.
The aim of the study was to investigate the interobserver agreement for categorical and quantitative scores of liver fibrosis.



Sixty-five consecutive biopsy specimens from patients with mixed liver disease etiologies were assessed by three pathologists using the Ishak and nonalcoholic steatohepatitis Clinical Research Network (NASH CRN) scoring systems, and the fibrosis area (collagen proportionate area [CPA]) was estimated by visual inspection (visual-CPA). A subset of 20 biopsy specimens was analyzed using digital imaging analysis (DIA) for the measurement of CPA (DIA-CPA).



The bivariate weighted κ between any two pathologists ranged from 0.57 to 0.67 for Ishak staging and from 0.47 to 0.57 for the NASH CRN staging. Bland-Altman analysis showed poor agreement between all possible pathologist pairings for visual-CPA but good agreement between all pathologist pairings for DIA-CPA. There was good agreement between the two pathologists who assessed biopsy specimens by visual-CPA and DIA-CPA. The intraclass correlation coefficient, which is equivalent to the κ statistic for continuous variables, was 0.78 for visual-CPA and 0.97 for DIA-CPA.



These results suggest that DIA-CPA is the most robust method for assessing liver fibrosis followed by visual-CPA. Categorical scores perform less well than both the quantitative CPA scores assessed here.
Translational Gastroenterology Unit, University of Oxford, United Kingdom.|Oxford Centre for Clinical Magnetic Resonance Research, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
Michael
M
Pavlides
Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Oxford, United Kingdom.
Jacqueline
J
Birks
Department of Histopathology, Oxford University Hospitals, Oxford, UK.
Eve
E
Fryer
Department of Histopathology, Oxford University Hospitals, Oxford, UK.
David
D
Delaney
Medical Sciences Division, University of Oxford, Medical Sciences Office, John Radcliffe Hospital, Oxford, UK.
Nikita
N
Sarania
Perspectum Diagnostics, Oxford, UK.
Rajarshi
R
Banerjee
Oxford Centre for Clinical Magnetic Resonance Research, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
Stefan
S
Neubauer
Translational Gastroenterology Unit, University of Oxford, United Kingdom.|Peter Medawar Building, University of Oxford, Oxford, UK.
Eleanor
E
Barnes
Medical Sciences Division, University of Oxford, Medical Sciences Office, John Radcliffe Hospital, Oxford, UK.|Department of Histopathology, Oxford University Hospitals, Oxford, UK.
Kenneth A
KA
Fleming
Department of Histopathology, Oxford University Hospitals, Oxford, UK.
Lai Mun
LM
Wang
D001706:Biopsy; D015331:Cohort Studies; D003094:Collagen / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging* / Q000473:pathology; D015588:Observer Variation
D003094:Collagen
Bland-Altman plot; Collagen proportionate area; Digital imaging analysis; statistic; κ