Automated image analysis in the study of collagenous colitis.
OBJECTIVE
The aim of this study was to develop an automated image analysis software to measure the thickness of the subepithelial collagenous band in colon biopsies with collagenous colitis (CC) and incomplete CC (CCi). The software measures the thickness of the collagenous band on microscopic slides stained with Van Gieson (VG).


METHODS
A training set consisting of ten biopsies diagnosed as CC, CCi, and normal colon mucosa was used to develop the automated image analysis (VG app) to match the assessment by a pathologist. The study set consisted of biopsies from 75 patients. Twenty-five cases were primarily diagnosed as CC, 25 as CCi, and 25 as normal or near-normal colonic mucosa. Four pathologists individually reassessed the biopsies and categorized all into one of the abovementioned three categories. The result of the VG app was correlated with the diagnosis provided by the four pathologists.


RESULTS
The interobserver agreement for each pair of pathologists ranged from κ-values of 0.56-0.81, while the κ-value for the VG app vs each of the pathologists varied from 0.63 to 0.79. The overall agreement between the four pathologists was κ=0.69, while the overall agreement between the four pathologists and the VG app was κ=0.71.


CONCLUSIONS
In conclusion, the Visiopharm VG app is able to measure the thickness of a sub-epithelial collagenous band in colon biopsies with an accuracy comparable to the performance of a pathologist and thereby provides a promising supplementary tool for the diagnosis of CC and CCi and in particular for research.
Department of Pathology, Roskilde Hospital, Roskilde, Denmark; Department of Pathology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Anne-Marie Kanstrup
AM
Fiehn
Digital Pathology, Visiopharm, Hørsholm, Denmark.
Martin
M
Kristensson
Department of Pathology, Copenhagen University Hospital, Hvidovre, Denmark.
Ulla
U
Engel
Department of Gastroenterology, Koege Hospital, Koege, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Lars Kristian
LK
Munck
Department of Pathology, Copenhagen University Hospital, Hvidovre, Denmark.
Susanne
S
Holck
Department of Pathology, Roskilde Hospital, Roskilde, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Peter Johan Heiberg
PJ
Engel
automated image analysis; collagenous colitis; incomplete collagenous colitis; microscopic colitis