Detection of postoperative relapsing/residual cholesteatomas with diffusion-weighted echo-planar magnetic resonance imaging

To assess the capability of echo-planar diffusion-weighted magnetic resonance imaging (MRI) (EPI-DWI) in diagnosing relapsing/residual cholesteatomas after canal wall-up mastoidectomy. In a blinded study design, we investigated with MRI, including standard spin-echo sequences, 18 patients evaluated with clinical examination and computed tomography (CT) suspected for relapsing/residual cholesteatoma 7 to 19 months after a canal wall-up mastoidectomy. Images were evaluated by two radiologists blinded to patients' identities, CT findings, and clinical data set, who decided in a consensus agreement whether there was a pathologic signal increase in the petrous bone in a single-shot EPI-DWI sequence. All the patients underwent a second tympanoplasty or revision surgery of the mastoidectomy cavity within 15 days after magnetic resonance investigation.Sensitivity, specificity, and predictive values were evaluated separately for standard sequences and EPI-DWI. In EPI-DWI, five of six patients with cholesteatoma showed a bright signal, whereas those patients with a noncholesteatomatous tissue showed no anomalies. The only misdiagnosed cholesteatoma was a pearl 2 mm in diameter. Sensitivity, specificity, and positive predictive values, and negative predictive values of EPI-DWI in diagnosing relapsing/residual cholesteatomas were 86, 100, 100, and 92%, respectively. EPI-DWI may be a useful tool in differentiating between cholesteatomatous and noncholesteatomatous tissues after closed cavity mastoidectomy. Further investigations are, however, required to establish the practical utility of EPI-DWI on larger series as a screening modality in the follow-up after closed cavity mastoidectomies.