Magnetic resonance imaging of the mastoid cavity and middle ear: prevalence and clinical significance of incidental abnormal findings in a nonotolaryngologic adult and pediatric population.

OBJECTIVE

The purposes of this study were to determine the prevalence of abnormalities in the mastoid cavity and middle ear in a nonotolaryngologic population and to correlate the results with clinical data.

DESIGN

Prospective, cross-sectional study.

SETTING

An academic tertiary care centre.

METHODS

We evaluated 100 adults and 30 children from May to July 2003. Patients who had a history of mastoid or middle ear surgery or were presently suffering from otitis media were excluded. Magnetic resonance imaging (MRI) was conducted for the suspected intracranial pathology.

MAIN OUTCOME MEASURES: The T2-weighted image was reviewed. The abnormality detected by MRI was divided into (1) mastoid cavity abnormality and (2) middle ear abnormality. All patients were asked to complete a questionnaire pertaining to the symptoms of the mastoid or middle ear pathology and the history of the otitis media. Also, their ears were examined carefully by an otoscope or otomicroscope.

RESULTS

In both groups, most of the abnormalities were found in the mastoid cavity. Analysis of the clinical data revealed that abnormal MRI findings of the mastoid cavity were significantly correlated to clinically significant mastoid or middle ear disease in adults.

CONCLUSIONS

Incidental MRI abnormalities in the mastoid cavity and middle ear detected in a nonotolaryngologic population were relatively uncommon compared with incidental paranasal sinus abnormalities. However, clinicians should remember the possibility of the pathologies that demand active treatment among these abnormalities, especially when a high signal abnormality is found in the mastoid cavity of an adult.