Role of non-echo-planar diffusion-weighted images in the identification of recurrent cholesteatoma of the temporal bone

BACKGROUND AND PURPOSE: The aim of the present prospective study was to verify the specificity of non-EPI DWI-MRI in patients operated for middle ear CHO who showed positivity at imaging performed 6 to 9 months after surgery and underwent second-look surgery. MATERIALS AND METHODS: All patients underwent 1.5-T non-EPI DWI-MRI 6 to 9 months after surgery: those showing a hyper-intense signal in the middle ear underwent a revision surgery, whilst the others are still under radiological follow-up and were not considered in this study. Two radiologists independently evaluated the images; both placed a standard region of interest inside the brightest part of the observed signal alteration on coronal HASTE-DWI images. The mean and maximum signal intensity values on the DWI images were recorded for each patient. A signal intensity ratio was calculated using the inferior temporal cortex and the background noise. RESULTS: One hundred and forty-three subjects were evaluated for a total of 210 ears. In 116 (170 ears), a normal non-EPI DWI-MRI was found with exclusion from this study, whilst twenty-seven subjects showed a high signal lesion inside the middle ear and underwent revision surgery. According to the ROC analysis, SI, SIRT and SIRTmax showed the best statistical values in comparison with the other parameters. CONCLUSIONS: Residual/recurrent CHO can be accurately detected using quantitative evaluation of non-EPI DWI-MRI.