【Objective】 To assess the clinical character of the HRCT in diagnosis of external auditory canal cholesteatoma. 【Methods】 Retrospectively analyzed the 27 cases patients with external auditory canal cholesteatoma

to observe the changes in the scute

lateral wall of the atticus

aditus ad antrum

tubotympanum

and ear ossicles. 【Results】 Fourteen ears for phase Ⅰ

external acoustic meatuses mild-moderate enlargement; 8 ears for phase Ⅱ

external acoustic meatuses obvious enlargement

bone destructions of mastoid processes were limited

tympanums were not involved; 5 ears for phase Ⅲ

bone destruction of mastoid processes were serious

tympanums were involved

all 5 ears?蒺 heads of malleuses and ear drums were pressed and moved inward

3 ears?蒺 malleuses and incuses were damaged to varying degrees

bone destructions of facial nerve vertical section was discovered in 1 case. 【Conclusion】 External acoustic meatus enlargement

inward movement of tympanic membrane

ossicular chain partly broken

mastoid cavity obstructive inflammation and so on are specific CT signs of the external acoustic canal cholesteatoma.