Diffusion-weighted imaging helps differentiate multiple sclerosis and neuromyelitis optica-related acute optic neuritis.

PURPOSE: To evaluate the apparent diffusion coefficient (ADC) values between multiple sclerosis (MS) and neuromyelitis optica (NMO)-related acute optic neuritis (ON) patients and predict their optic nerve atrophy of optic coherence tomography (OCT) parameters.

MATERIALS AND

METHODS

Nineteen MS and 15 NMO-related acute ON patients who underwent a diffusion-weighted imaging sequence in 3.0 Tesla MR scanner and a follow-up OCT examination after 6 months were included. The ADC values, thickness of the retinal nerve fiber layer (RNFL) and the macular ganglion cell complex (GCC) between MS and NMO related ON were assessed.

RESULTS

The mean ADC value of the NMO-ON, (0.691 ± 0.195[SD]) × 10-3 mm2 /s, was significantly smaller (P = 0.0133) than that of MS-ON. The mean ADC value of MS-ON, (0.879 ± 0.144) × 10-3 mm2 /s, was significantly smaller (P < 0.0001) than that of control group, (1.025 ± 0.067) × 10-3 mm2 /s. Using an ADC value smaller than 0.830 × 10-3 mm2 /s as the threshold value for differentiating MS-ON from NMO-ON patients, the highest accuracy of 76.7%, with 75.0% sensitivity and 78.3% specificity, was obtained. The ADC value measured at the acute stage of ON was correlated with the thickness of the RNFL (r = 0.441; P = 0.006) and the GCC (r = 0.526; P < 0.0001) after 6 months.

CONCLUSION

The ADC value might be helpful for differentiating MS-ON from NMO-ON patients. The decreased ADC value was correlated with optic nerve atrophy on OCT.

LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;45:1780-1785.