الفهرس 
Radiological Anatomy of the Middle EarOnly 14 pages are availabe for public view
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Abstract
Background: CT is the primary tool for the evaluation of the extent and complications of middle ear cholesteatoma. However, it is inaccurate in differentiation of cholesteatoma from granulation or fibrous tissue as well as other middle ear pathologies e.g. cholesterol granuloma. MRI can be a beneficial tool in the confirmation or exclusion of cholesteatoma.
Aim of the Work: The aim of work is to evaluate the role of MRI diffusion weighted images in the assessment of cholesteatoma. This will be compared with the results of the CT examination. The results will be confirmed by intra-operative findings and histopathological data.
Patients and Methods: 30 patients with cholesteatoma suspected clinically or by CT examination or known patients with cholesteatoma with suspected post-operative recurrence were tested by MR thin cut multi-shot EPI diffusion weighted images of the skull base that were acquired by using a 1.5-T Achieva system in our department.
Results: Our study revealed that the use of thin cut multi-shot EPI is a beneficial tool in the evaluation of both primary and recurrent cholesteatoma with excellent specificity that reduces the need of second look surgeries in multiple cases. It also revealed improved sensitivity and smallest detectable size compared to SS-EPI techniques. However, it shows relatively less sensitivity compared to non-EPI techniques with the smallest detectable size being about 4.5 mm..
Conclusion: DWI is a beneficial tool in the evaluation of both primary and recurrent cholesteatoma with excellent specificity that reduces the need of second look surgeries in multiple cases. The use of multi-shot diffusion weighted techniques improved its sensitivity significantly compared to single shot techniques. It still could not detect lesions smaller than 4 mm.
Key words: DWI, MRI, EPI, MS, SS, Cholesteatoma.