Patients and images
A total of 12 patients undergoing endoscopic resection of middle ear
cholesteatoma were prospectively enrolled in the present study. All
patients provided informed consent and the study was approved by the
local ethical committee (Kantonale Ethikkommission Bern KEK2019-00555).
At the end of the cholesteatoma resection a final endoscopic check for
residual disease is routinely performed. During this complete check of
the middle ear, zones with residual tissue (cholesteatoma, granulation
tissue, but not macroscopically normal mucosa) were photographed using
the three DIE modalities clara (normal image), spectra A and spectra B
as illustrated in Figure 1. Light intensity standardized to 70% for
every imaging modality (PowerLED300, Karl Storz, Tuttlingen, Germany).
Thereafter the photographed tissue was removed and sent for separate
histopathological evaluation. From the histopathological analysis 10
sites of residual cholesteatomatous tissue and 10 sites of
non-cholesteatomatous tissue (e.g. granulation tissue, mucosa) were
selected. Accordingly, 20 different surgical sites provided the final
set of 60 images (each site registered with 3 different image
modalities) representing residual cholesteatoma or residual granulation
tissue for further analysis.