Detecting Optic Nerve Lesions in Clinically Isolated Syndrome and Multiple Sclerosis: Double-inversion Recovery Magnetic Resonance Imaging in Comparison with Visually Evoked Potentials

Background And Aim: Optic neuritis (ON) is a frequent manifestation of multiple sclerosis (MS), traditionally diagnosed clinically and by visually evoked potentials (VEP). However, ON can also be assessed by MRI. Here we compare the diagnostic performance of 3D-double inversion recovery-MRI (3D-DIR) and VEPs in patients with definite MS or clinically isolated syndrome (CIS).

Methods: 39 patients and 17 healthy controls were studied. Whole-brain-3D-DIR images (3T) were independently assessed for DIR-hyperintense optic nerve lesions (DHLs) by two neuroradiologists, and results related to quantitative VEP-parameters.

Results: Interrater concordance for DHLs was high (κ = 0.82). No DHLs were observed in controls. In patients, abnormal VEPs, i.e. prolonged latencies, diminished amplitudes or abnormal latency or amplitude differences (re contralateral nerve) of the P100-component, were observed in 22, and DHLs in 32 of 78 optic nerves, the latter including 11 nerves with normal VEPs, 10 without clinical signs or history of ON, and 6 with both normal VEPs and no clinical evidence for ON. Using either abnormal VEPs and/or presence of DHLs and/or clinical evidence for ON as a compound reference criterion of optic nerve affection, sensitivity was significantly higher for 3D-DIR than for VEPs (91%, 95%-CI 77-98% vs. 63%, 95%-CI 45-79%, respectively, p = 0.006).

Conclusion: DHLs are highly specific for optic nerve pathology. In the context of MS, 3D-DIR-MRI is a suitable tool to reveal acute or chronic optic nerve lesions and more sensitive than VEPs. The significance of optic nerve involvement in the diagnostic classification of CIS vs. definite MS requires further study.