The use of MRI in a tertiary smell and taste clinic: Lessons learned based on a retrospective analysis.

Background: Olfactory dysfunction (OD) is a common but underreported problem that can significantly impact a patient's quality of life. OD is prevalent in over 5% of the adult population and can be broadly categorised into conductive and sensorineural causes. Magnetic Resonance Imaging (MRI) can form part of the diagnostic work up, although its exact role is often debated.

Objectives: The aim of this study was to evaluate the value of MRI in managing patients with OD.

Design/method: A retrospective analysis of the records of patients presenting to a national smell and taste clinic over a 5-year period was performed. Variables included demographics, endoscopic findings, final diagnosis, psychophysical smell test and imaging results.

Results: A total of 409 patients, with an age range of 10-93 years, underwent clinical assessment and smell testing, of which 172 patients (42%) had MRI scans. Imaging in younger age-groups was associated with a higher rate of positive findings, however identifiable causes for OD were recorded across the range. MRI provided both diagnostic and prognostic information in those with idiopathic, traumatic and congenital causes of OD. For example, MRI provided information on the extent or absence of gliosis in those with a head trauma history allowing further treatment and prognosis.

Conclusion: We recommend the adjunct use of MRI in patients with a clear history and examination findings of head injury, congenital cases and in apparent idiopathic cases. MRI should be requested to compliment clinical findings with a view to aiding decision-making on treatment and prognosis independent of patient's age.