Fusion of computed tomography and diffusionweighted magnetic resonance images for detection of primary, residual and recurrent cholesteatoma of the middle ear

Background:  At present,  computed  tomography  (CT)  is recognized  as  method for primary diagnosis of middle ear disorders. More accurate diagnosis  of  cholesteatoma  is based  on  a  sequence  of non-echo   planar  diffusion-weighted magnetic  resonance imaging. The choice of the type  of surgery depends on cholesteatoma size and location. Aim: To assess the possibility of fusion of CT and magnetic  resonance images (MRI) to determine the  precise location of the  middle ear cholesteatoma. Materials and methods: The CT and diffusion-weighted (DW) images of 24 patients  with chronic suppurative otitis media, including 12 with newly diagnosed and 12 with relapsing cholesteatoma were fused. The patients underwent the  standard  CT and  MRI, including DW-MRI.  CT  and  DW-MRI  images  were  fused with determination of exact size and location of cholesteatoma in the middle ear cavity. Results: The exact location and size of the cholesteatoma were identified. The study results were compared with intraoperative data. The use of fused CT and DW images  had  the  sensitivity in determination of cholesteatoma location and size of 96%, specificity of 100%, positive predictive value of 100%, and negative  of 96%, which all were higher than the corresponding values for CT and MRI assessments. Conclusion: Fusion of CT and DW-MRI allows for determination of the precise localization of cholesteatoma, partial exclusion of false-positive  results   correlate   and   for  comparison   of the  lesion with important bone  landmarks. The method may be  useful for the  surgeon  both  in planning of primary surgery, as well as for repeated revision of the postoperative cavity.