MRIs Not Cost Effective for Evaluating Idiopathic Olfactory Loss

How cost effective is the use of magnetic resonance imaging (MRI) for evaluating patients with idiopathic olfactory loss?

Background: Olfactory disorders have many etiologies, including post-upper respiratory illness, trauma, toxic exposures, obstruction and congenital issues, Parkinson’s disease, multiple sclerosis, and Alzheimer’s disease. Often, the etiology remains unknown even after extensive testing. Increasing healthcare costs make it important to critically analyze expensive diagnostic techniques such as MRI.

Study design: Retrospective chart review of 839 patients at a tertiary center from July 1998 through October 2011.

Setting: University of Cincinnati Neurosensory Disorders Center.

Synopsis: Data from radiologists’ interpretations of brain MRIs were used, and abnormal MRI findings were then classified as either incidental or potentially responsible for olfactory disorders. Cost analysis was based on an average hospital charge of $2,500. Of 839 patients, 247 were identified as presenting with presumed idiopathic olfactory loss. Brain MRI data were available for 130 of those patients; a total of 4.6% of these MRIs were considered abnormal, with hypertensive encephalopathy, left frontal lobe vascular malformation, right third ventricle mass, left olfactory bulb atrophy, possible left posterior fossa schwannoma, and multiple white matter abnormalities suggestive of multiple sclerosis (MS) presenting in one patient each. Only the MRI suggestive of MS was considered potentially causative. The estimated charge per abnormality was approximately $54,250, while the estimated charge per MRI finding thought to be responsible for olfactory loss was $325,000. There were some limitations, including a lack of standardization in diagnostic evaluations, a lack of MRI testing in all idiopathic patients, and possible selection bias in terms of patient recommendation to the center.

Bottom line: The routine use of MRI in patients presenting with isolated idiopathic olfactory loss may be unwarranted, because the diagnostic yield of the brain MRIs was low.

Citation: Hoekman PK, Houlton JJ, Seiden AM. The utility of magnetic resonance imaging in the diagnostic evaluation of idiopathic olfactory loss. Laryngoscope. 2014:124:365-368.