Efficacy of diffusion-weighted magnetic resonance imaging in the diagnosis of middle ear cholesteatoma.

Objective: This study evaluated the usefulness of diffusion-weighted magnetic resonance imaging (DWI) in the diagnosis of middle ear cholesteatoma.

Methods: We performed DWI on 73 patients suspected of having middle ear cholesteatoma, including 21 revision cases. Magnetic resonance imaging was performed with 1.5T units using diffusion-weighted spin-echo-type echo planar imaging (DWI).

Results: Of 73 subjects, 59 had cholesteatoma that consisted of 41 primary acquired cholesteatoma, 13 had residual and/or recurrent cholesteatoma, four had congenital cholesteatoma, and one had iatrogenic cholesteatoma. Positive DWI findings were observed in 42 subjects and negative findings in 31 subjects. The sensitivity, specificity, and positive and negative predictive values of DWI for cholesteatoma were 69.4%, 92.8%, 97.5%, and 41.9%, respectively. In the case of 34 patients who were positive for cholesteatoma on both otoscopic and CT examinations, 33 were diagnosed with cholesteatoma. Of the remaining 39 subjects with one or both negative results for cholesteatoma, the sensitivity, specificity, positive predictive value, and negative predictive value of DWI were 57.6%, 92.3%, 93.7%, and 52.1%, respectively. Cholesteatoma mass diameters were less than 5mm in 10 out of 18 subjects with both cholesteatoma and negative DWI findings. Of the 21 subjects who received revision surgery, the sensitivity, specificity, and positive and negative predictive values of DWI for residual or recurrent acquired cholesteatoma were 71.4%, 100%, 100%, and 63.6%, respectively.

Conclusions: Since DWI clearly showed high specificity and positive predictive value, it is useful for diagnosing middle ear cholesteatoma, including postoperative recurrent cholesteatoma of 5mm diameter or larger. DWI could sufficiently detect cholesteatoma with one or both negative results on otoscopic and CT examinations, but it was difficult to detect cholesteatoma of less than 5mm diameter using DWI owing to the tiny mass and small volume of debris.