CT and MR imaging after middle ear surgery

Imaging of the postoperative middle ear

The aim of this article is twofold: (a) to present the principles and the indications of surgical treatment of middle ear pathologies; and (b) to review the imaging findings after middle ear surgery, including the normal postoperative aspects and imaging findings in patients presenting with unsatisfactory surgical results or with suspicion of postoperative complications. This review is intentionally restricted to the most common diseases involving the middle ear: chronic otitis media and otosclerosis. In these specific fields of interest, CT and MR imaging play a very important role in the postoperative follow-up and in the work-up of surgical failures and complications.

Diffusion-weighted MR imaging of cholesteatoma in pediatric and adult patients who have undergone middle ear surgery

OBJECTIVE

The aim of this prospective study was to determine the role of diffusion-weighted MR imaging combined with conventional MR imaging for the detection of residual or recurrent cholesteatoma in patients who have undergone middle ear surgery.

SUBJECTS AND METHODS

Twenty-two patients who had undergone resection of cholesteatoma were referred for MR imaging. MR imaging (1.5 T) was performed using a diffusion-weighted single-shot spin-echo echoplanar sequence, a proton density and T2-weighted double-echo turbo spin-echo sequence, and T1-weighted spin-echo sequences before and after IV injection of gadopentetate dimeglumine (0.1 mmol/kg of body weight). An experienced reviewer evaluated the diffusion-weighted MR images for the presence of a high-signal-intensity cholesteatoma. Imaging findings were correlated with findings from surgery in 17 patients and with findings from clinical follow-up examination in five patients.

RESULTS

Diffusion-weighted MR imaging combined with conventional MR imaging depicted 10 of 13 cholesteatomas (sensitivity, 77%). The three lesions that were missed were smaller than 5 mm. All the MR images of patients without cholesteatoma were correctly interpreted as showing negative findings for cholesteatoma (specificity, 100%). The positive predictive value and negative predictive value were 100% and 75%, respectively.

CONCLUSION

Diffusion-weighted MR imaging combined with conventional MR imaging can confirm residual or recurrent cholesteatoma in patients who have undergone middle ear surgery by showing a high-signal-intensity lesion. Because tumors smaller than 5 mm may be missed, a diffusion-weighted MR imaging study with negative findings does not exclude small residual or recurrent cholesteatoma.