Clinical implications
On MRI imaging, cholesteatoma shows a T2 hyposignal, DW-MRI hypersignal, and no T1 hypersignal. However, a DW-MRI hypersignal is not synonymous of cholesteatoma diagnosis. Indeed, this diagnosis relies on the importance of a proper otoscopic examination, a suggestive medical history, CT scan data and analysis of other MRI sequences, including T1-weighted sequence, to rule out other etiologies of middle ear DW-MRI hypersignal.
Despite these false positives, DW-MRI is a key element for cholesteatoma diagnosis which does not require contrast-enhanced MRI. Indeed, this may be an important element to consider since gadolinium can lead to nephrogenic systemic fibrosis and brain tissue retention; Gadolinium tends to deposit cumulatively in the brain of patients with normal hepatobiliary function and intact blood-brain barrier. This has to be put into perspective given that these children may have to perform repetitive MRI scans to detect any cholesteatoma recurrence.
DW-MRI duration is about 20 minutes. The average age of our patients was 14.2 ± 5.3 years old. They are consequently old enough and therefore do not require a general anesthesia to obtain a satisfactory exam quality. However, if the MRI exam has to be performed under general anesthesia, a second look surgery may then be preferable, since surgery is considered as the gold standard and it allows retrieval of the cholesteatoma.
MRI is very effective, especially for detecting cholesteatomas’ recurrence and can be easily carried out since it does not require gadolinium injection nor sedation in older patients.