Diagnostic accuracy of diffusion-weighted MR imaging versus delayed gadolinium enhanced T1-weighted imaging in middle ear recurrent cholesteatoma: A retrospective study of 39 patients

Objective: MR imaging using diffusion-weighted (DW) images and delayed gadolinium-enhanced T1-weighted images is evolving into an alternative to second look surgery in detection of recurrent cholesteatomas. The aim of this study was to retrospectively compare the DW images, the post-gadolinium T1-weighted images and the combination of both methods in this indication.

Patients and methods: We retrospectively evaluated the MR examination of 39 patients clinically suspected for a recurrent cholesteatoma. Patients in the study underwent DW sequences, delayed gadolinium enhanced T1-weighted sequences as well as standard uninjected protocol using T1 and T2 sequences. Three blinded radiologists evaluated three data sets: a set of post-gadolinium T1-weighted images, a set of DW images and a set of the combination of both methods. The interobserver agreement was evaluated and the diagnostic accuracy of each method was described by sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The performances of the three techniques were also evaluated using ROC curves, from which the AUC were compared. Results were compared with surgical results or a two-year follow-up.

Results: The overall sensitivity and specificity were respectively 63% and 71% for the post-gadolinium T1-weighted images, 88% and 75% for the DW images and 84% and 75% for the combined images. The PPV and NPV were respectively 89% and 33% for the post-gadolinium T1-weighted images, 93% and 62% for the DW images and 93% and 55% for the combined images. The sensitivity and the NPV were significantly different between the three methods (P<0.0001 and P=0.027). There was no statistically significant difference in specificity or PPV between the three methods (P=0.931 and P=0.650). The diagnostic accuracy evaluated with the AUC showed no statistically significant difference between the DW images and the combined images (P=0.433).

Conclusion: MR imaging reliably identifies those patients suspected for recurrent cholesteatoma who require a surgical second look by using DW MR imaging. The combination with delayed gadolinium enhanced T1-weighted sequences does not significantly increase the diagnostic accuracy of the examination.