Diffusion-weighted imaging for cholesteatoma evaluation.

Computed tomography (CT) has long been considered the optimal imaging technique for the detection of cholesteatomas. However, this modality often lacks specificity, particularly in patients with an absence of definite bony erosion or a history of surgical excision. Several investigators have proposed magnetic resonance imaging with diffusion-weighted imaging (DWI) as a means of diagnosing the presence and extent of cholesteatomas, particularly when CT results are equivocal. The rationale for the use of DWI is that cholesteatomas demonstrate restricted diffusion and granulation tissue does not. In this retrospective study, we review our experience with 12 patients who had undergone DWI for evaluation of a mass in the middle ear, mastoid, or petrous apex. Ten of these patients had previously undergone middle ear surgery, 8 for cholesteatoma resection. On DWI, 9 patients demonstrated restricted diffusion. Of these, 8 patients underwent surgical resection, and all were found to have had a cholesteatoma. Of the 3 patients who had not demonstrated restricted diffusion on DWI, 2 did not undergo surgery and the other was found to have only chronic inflammation at surgery. Based on our limited experience, we believe that DWI can be useful in confirming the diagnosis of cholesteatoma. Moreover, it may alter patient management, particularly in patients whose previous tympanoplasty/mastoidectomy does not allow for an adequate clinical inspection of the middle ear cavity.