Using Non-Echoplanar Diffusion Weighted MRI in Detecting Cholesteatoma Following Canal Wall Down Mastoidectomy - Our Experience with 20 Patient Episodes.

OBJECTIVE

To our knowledge, there is no study exploring specifically the diagnostic performance of diffusion-weighted imaging (DWI) in patients with previous canal wall down (CWD) surgery when combined with appropriate clinical evaluation. The aim of the present study was to evaluate the performance of DWI in the detection of residual or recurrent disease in patients who have had a previous CWD mastoidectomy.

MATERIALS AND

METHODS

We identified 13 patients with a CWD mastoidectomy subsequently having at least one further DWI prior to further mastoid exploration that generated a total of 20 patient episodes. Magnetic resonance imaging was performed on a 1.5 T superconductive unit using a standard head matrix coil. Coronal 2 mm thick TSE T2-weighted images (TR: 4640 ms; TE: 103 ms; matrix: 245,384; field of view: 150×200 mm) were performed. Operative findings were reviewed for all 20 patient episodes to compare DWI findings with intraoperative findings. Based on this, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated.

RESULTS

DWI had a sensitivity of 93%, specificity of 60%, PPV of 87%, NPV of 75%, and accuracy of 80%.

CONCLUSION

Given the high sensitivity of DWI in the detection of residual or recurrent disease, the present study supports DWI as a useful tool in the detection of residual or recurrent cholesteatoma in cases following CWD surgery, where clinical acumen suggests an ongoing disease process despite no overt cholesteatoma being visible.