Postoperative non-echo-planar diffusion-weighted magnetic resonance imaging changes after cholesteatoma surgery: implications for cholesteatoma screening.

OBJECTIVES: Diffusion-weighted (DW) magnetic resonance imaging (MRI) is emerging as an alternative to second-look surgery in ruling out residual or recurrent disease after cholesteatoma eradication. However, the DW MRI appearances of postoperative or inflammatory mucosal changes have not been well investigated, thus rendering the interpretation of postoperative DW MRI difficult in the presence of mucosal reactions. We investigated the turbo-spin echo (TSE) DW MRI changes of the middle ear and mastoid mucosa after cholesteatoma surgery and compared these with the TSE DW MRI features of cholesteatoma with an aim to identify a rapid and cost-effective purely DW MRI sequence that can be used to screen for cholesteatoma. STUDY DESIGN: A prospective comparative study. SETTING: A tertiary referral center in Western Australia. PATIENTS: Patients undergoing revision or second-look cholesteatoma surgery. INTERVENTION: Patients underwent 3 to 6 monthly half-Fourier-acquisition single-shot turbo-spin-echo TSE DW MRI before their second surgery. The MRI findings were then correlated with the intraoperative findings at second-look surgery 6 to 17 months after primary surgery or of revision surgery in the cases that were referred from other centers. MAIN OUTCOME MEASURE: Detection of cholesteatoma and noncholesteatoma mucosal changes on TSE DW MRI, compared with the gold standard of findings at second surgery. RESULTS: Twenty-two patients underwent 23 second-look or revision procedures. All patients had DW MRI before their "second-look" or revision surgery. TSE DW MRI detected cholesteatomas in 7 patients whom all had disease confirmed at second-look or revision surgery. In 16 cases shown to be negative on DW MRI for cholesteatoma, all were confirmed to be disease-free on second-look surgery. Cholesteatomas were shown to produce a TSE DW MRI signal clearly distinct from the spectrum of imaging findings encountered in postoperative mucosal changes. CONCLUSION: TSE DW MRI holds great promise in screening for cholesteatoma as an alternative to exploratory second-look surgery.