Effectiveness of Non-Echo-Planar Diffusion-weighted MR Imaging, as a Diagnostic Imaging of Middle Ear Cholesteatoma

Abstract

Patients with cholesteatoma are commonly evaluated by using computed tomography (CT). Although CT is useful for anatomical analysis for surgical landmark, it cannot discriminate cholesteatoma from other soft tissue. This limits its preoperative and postoperative usefulness. In Japan, it has been reported that echo-planar diffusion-weighted MR imaging (EP DW) is useful for diagnostic imaging of cholesteatoma. However, EP-DW shows important artifacts and has a low resolution, thus missing small lesions. Bert De Foer et al. reported that non-echo-planar diffusion-weighted MR imaging (non-EP DW) has a thinner section thickness and higher imaging matrix and is less prone to susceptibility artifacts than EP DW. We have been using non-EP DW for detection of middle ear choleateatoma since Jan. 2011. We evaluated 63 patients with middle ear diseases with non-EP DW and operated on 30 ears. Non-EP DW was positive in 21 ears preoperatively and all showed cholesteatoma during surgery. The smallest size of non EP DW positive cholesteatoma was 3mm. Nine ears were negative (1 cholesteatoma, 1 cholesterol granuloma, 1 glomus tumor, 1 chronic otitis media, 3 otitis media with effusion, 1 ossification of external auditory meatus, 1 postoperative cholesteatoma with no residual cholesteatoma). We concluded that non-EP DW is useful for preoperative diagnosis of cholesteatoma, especially in cases with recurrent or residual cholesteatoma.