Quantitative Evaluation of Signal Intensity of Magnetic Resonance Images in Optic Neuritis

Abstract

Abstract:We have evaluated the signal intensity of magnetic resonance (MR) images of the optic nerve quantitatively in 25 patients with unilateral acute optic neuritis (ON). MR imaging was performed with a 1.5 Tesla unit before treatment within 2 weeks after the onset of ON. Four coronal fat-suppressed T2-weighted images were obtained at 5, 10, 15, and 20 mm behind the eye. The ratio of the signal intensity of the MR images from the optic nerve to that of the white matter of the frontal lobe was calculated and we compared the signal intensity ratio of the affected eyes to the fellow healthy eyes. For statistical analysis paired t-test was used. At all 4 sections, the mean signal intensity ratio of the affected eyes is statistically significant higher than fellow eyes. The 11 patients showed optic disc swelling in the affected eyes and in all these 11 eyes had a higher signal intensity at 5 mm behind the eye compared with the fellow eye. From our present results, we cannot refer to the sensitivity of our method, because we did not use our present methods to other diseases. But with this method we think inter-image and inter-observer variability must reduce. Further studies are required about the sensitivity and the relation between the pathological condition of optic nerve and the signal intensity ratio.

Evaluating the Utility of a Postprocessing Algorithm for MRI Evaluation of Optic Neuritis

“…Challenges of MR imaging of the optic nerve include its small size, heterogeneity of the surrounding orbital tissue, and artifacts related to eye movements or the presence of surrounding orbital fat. [13][14][15][16][17][18][19] The optic nerve signal is best compared with normal white matter in the brain. 20 However, the lack of proximity of the optic nerve to the white matter and different intensities of surrounding structures make this comparison difficult.…”

Non-invasive Classification of Orbital Tissue Pathology Based on Texture Analysis Parameters from Magnetic Resonance Images

“…5 Bahl et al 23 or STIR signals and disease activity or therapy responses. [26][27][28][29] Other quantitative MRI studies include the assessment of signal intensities on T2-weighted images or STIR in patients with optic neuritis [30][31][32] and apparent diffusion coefficient (ADC) measurement of the lacrimal gland in Sjögren's syndrome. 33 Sepahdari et al 34 and Fatima et al 35 were able to characterise orbital tissues using diffusion-weighted MRI and ADC value, and the ability to differentiate between malignant and benign orbital tumours.…”