Index for the Diagnosis of Cholesteatoma on the Temporal Bone CT

Kim, Jeong Kyu; Yeo, Chang Ki; Kim, Jin Soo; park, Jin Hyung; Kim, Yong Sun; Lee, Sang Heun; Cho, Tae Hwan

Abstract

BACKGROUND AND OBJECTIVES: Diagnosis of cholesteatoma on temporal bone CT relies on secondary factors such as bony destructions and ossicular erosions combined with abnormal soft tissue density. But some non-cholesteatomatous otitis media have such findings and some cholestatoma do not have such findings, so its diagnosis is a difficult problem. We tried to find an index for accurate diagnosis of cholesteatoma on the CT findings. MATERIALS AND METHOD: Sixty-five patients with chronic otitis media (COM) with cholesteatoma and 55 patients with COM without cholesteatoma underwent preoperative CT scan followed by surgical exploration. Operative notes and radiographs were reviewed and data were collected regarding the nature of soft tissue density, state of ossicles, presence or absence of bone destructions. We defined the cholesteatoma factor as that which has significantly higher incidence in cholesteatoma group than non-cholesteatoma group among the data, and defined the cholesteatoma index as the number of cholesteatoma factors on temporal bone CT of one patient.
RESULTS
The cholesteatoma factors were scutum destrucion, tegmen destruction, lateral semicircular canal destruction, external auditory canal destruction, sigmoid plate destruction, attic wall destruction, aditus ad antrum widening, antral wall destruction, ossicular superstructure destruction, and ossicular medial displacement. The probability of presence of cholesteatoma was 15.9%, 41.7%, 75.0%, 88.9%, 100% when the cholesteatoma index was 0, 1, 2, 3, >or= 4, respectively.
CONCLUSIONS
We suggest the cholesteatoma index as a useful tool of diagnosis of cholesteatoma on the basis of temporal CT findings.