Comparison of computed tomography and magnetic resonance imaging for evaluation of cholesteatoma with labyrinthine fistulae

Objectives/Hypothesis: To compare preoperative computed tomography (CT) and magnetic resonance imaging (MRI) findings to the clinical features in patients with middle ear cholesteatoma with labyrinthine fistulae. Study Design: Retrospective case series. Methods: Twenty-eight patients who underwent surgery for middle ear cholesteatoma with one or more labyrinthine fistulae confirmed by CT were studied. Preoperative imaging analysis was performed using three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) MRI. Fistula size measured by CT and the signal intensity ratio (SIR) between the affected lesion in the inner ear and the cerebellum measured by 3D-FLAIR MRI were evaluated with respect to the clinical features and surgical findings. Results: The SIR was not correlated with fistula size. The hearing threshold determined by preoperative bone conduction correlated with the SIR, especially in patients with acute sensorineural hearing loss, but it did not correlate with fistula size. Patients with fistula symptoms had a significantly higher SIR than those without symptoms, and similar findings were observed in patients with an active infection. Patients with a larger fistula or higher SIR tended to have a deeper fistula and a more adhesive fistula matrix at operation. Conclusions: SIR was more strongly correlated than CT findings to the clinical status of patients with labyrinthine fistulae caused by cholesteatoma. Adhesion of the cholesteatoma matrix to the membranous labyrinth correlated with the SIR; thus, SIR may accurately reflect the extent of inner ear dysfunction with a labyrinthine fistula.