[Postoperative MRI findings after cholesteatoma surgery]

This study was designed to show MRI findings of postoperative middle ear pathologies and to discuss the usefulness of Gadolinium-enhanced MRI in evaluating the postoperative state of cholesteatoma. Thirty-eight ears which underwent intact canal wall tympanoplasty for cholesteatoma were examined. Recurrent cholesteatoma was detected as an iso-intensity area on T1-weighted images with negative enhancement. Notably, residual cholesteatoma were generally depicted as a round iso-intensity area with negative enhancement. Residual cholesteatoma less than 5mm in diameter were, however, not generally detectable with our MRI scanner. Granulation tissue can be separated from cholesteatoma as an area with positive enhancement. Cholesterol granuloma shows a characteristic high signal pattern on both T1 and T2-weighted images. Hypovascular fibrous tissue and fluid collection may be depicted as a pattern similar to that of cholesteatoma. However, the signal is usually more homogeneous than that of cholesteatoma. We conclude that Gadolinium-enhanced MRI is useful for detecting postoperative cholesteatoma and avoiding unnecessary second-look operations after cholesteatoma surgery, by the canal-up procedure.