Learning Objectives: Shed some light on role of MRI for cholesteatoma.

Background: Although the diagnosis of cholesteatoma is in nearly all cases achieved by a meticulous otomicroscopical or endoscopical examination, imaging is usually required for a better definition of the extension of the pathology as well as to evidentiate eventual bony erosions. Non ECHO-planar diffusion weighted magnetic resonance (non-EPI DW MRI) has been recently acquired as an important diagnostic tool in case of cholesteatoma, with high rates of sensitivity and specificity. At the ENT Unit of Sant'Andrea Hospital in Rome, Italy, this technique is regularly applied since five years especially for following-up after surgery. In this study, specific protocols are presented to be applied in different clinical situations.

Material and Methods: A consecutive number of subjects affected by cholesteatoma were scheduled for surgery. Both primary and recurrent cases were taken into consideration. Primary cases were subdivided in limited and extended cases, while recurrent cases comprised both routine cases and sequels from subtotal petrosectomy with blind sac closure of the external meatus. In the extended cases and in petrous bone cholesteatoma cases, non-EPI DW MRI was planned soon after surgery (within 1 month) and 3, 6 and 12 months after surgery. In the limited cases, it was only planned 12 months after surgery.

Results and Discussion: Non-EPI DW MRI has proven to be highly sensitive for detecting residual pathology with only rare cases of false positivity. The early application of this technique in selected invasive cases enabled to reassure the surgeon on the performed surgical procedure or give notice of the expected residual tissue left in particular cases where other priorities were taken into consideration (e.g, facial nerve function).