The diagnostic and economic yield of neuroimaging in neuro-ophthalmology

Diagnostic studies such as computed tomography scans (CT) and magnetic resonance imaging (MRI) are ordered frequently in neuro-ophthalmic practice, although the diagnostic yield and cost-effectiveness of these tests have been studied for only a few conditions. We assessed the diagnostic and economic yield of CT and MRI across all patients evaluated in a neuro-ophthalmology practice.

This retrospective review included all patients referred by the division of neuro-ophthalmology at the Scheie Eye Institute for CT, CT angiography, MRI, MRA, or magnetic resonance venography over a 12-month period. Abnormal imaging findings were categorized as significant (one that elicited changes in management) and/or relevant (one that related to the patient's neuro-ophthalmic complaint or examination findings). The diagnostic yield of the test ordered was analyzed according to the patient's chief complaint, neuro-ophthalmic examination findings, and indication for imaging. The total costs for each diagnostic group and costs per significant finding were calculated using the global Resource-Based Relative Value Units for each examination from the Centers for Medicare and Medicaid Services Web site.

Two hundred eleven imaging studies in 157 patients were evaluated. 28.9% (95% confidence interval, 22.5%-36.2%) of imaging studies had significant abnormalities relevant to the neuro-ophthalmic complaint. Imaging obtained for evaluation of progressive optic nerve dysfunction and cranial nerve palsy had statistically significant higher diagnostic yield than studies performed for other reasons. Total cost of all imaging studies performed was $107,615.72. Cost per clinically significant and relevant finding was $1,764.19.

In comparison to the diagnostic yield of neuroimaging studies in other specialties, CT and MRI of the brain requested by neuro-ophthalmologists provide significant and relevant data at a reasonable cost.