Diffusion-weighted MR imaging for evaluation of pediatric recurrent cholesteatomas

To compare the efficiency of diffusion-weighted MR imaging (MRI) vs. high resolution CT in predicting recurrent or residual cholesteatoma in children who underwent prior middle ear surgery.

Prospective study.

Tertiary care university hospital.

Seventeen patients (4 with 2 recurrences) aged 5-17 years (mean 11.4) previously surgically treated for a cholesteatoma of the middle ear, were included for follow-up with systematic CT scan and MRI, between 2005 and 2007.

CT scan was performed on a Siemens Somaton 64 (0.5/0.2 mm slices reformatted in 0.5/0.3 mm images), parallel and perpendicular to the lateral semi-circular canal for each ear (100 mmx100 mm FOV). MRI was undertaken on a Siemens Avanto 1.5 T unit, with an adapted protocol for young children. Diagnosis of recurrent cholesteatoma was based on the evidence of a hyperintense image at B1000 on diffusion-weighted images. Results of CT scan and MRI were compared with operative diagnosis.

Nine patients had a positive MRI, among which 8 had cholesteatoma confirmed during revision surgery. In the 12 negative MRI cases, 5 were positive on revision surgery. None of these lesions was over 3mm. Two of them were diagnosed on the CT scan. CT scan alone had a positive predictive value of 75%, and a negative predictive value of 58%.

Diffusion-weighted MRI is associated with a high positive predictive value for the detection of recurrent cholesteatoma. CT scan remains the first choice imaging technique. In case of doubtful CT scan, diffusion-weighted MRI could confirm a recurrence or, when negative, avoid second-look surgery.