Measurement of human optic nerve's diameter using magnetic resonance imaging (MRI) images

The measurement of human optic nerve is a challenging task due to its small size. This study attempted to measure the diameter of the optic nerve on Magnetic Resonance Imaging (MRI) images using segmentation and Gaussian function fitting. The MRI images were acquired using T1-Weighted (T1W) and T2-Weighted (T2W) sequences with an axial-oblique orientation which include both optic nerves. These sequences were repeated on both 1.5T and 3.0T scanners for comparison. Eleven healthy volunteers and fourteen patients with optic neuritis were scanned and their data were analyzed using Matlab program. One or three peaks Gaussian function was used to fit the intensity line profile across the cross-section of the optic nerve. The mean optic nerve's diameter for the optic neuritis patients was found larger than the healthy volunteers' optic nerve's diameter, on both T1W and T2W images, and on both 1.5T and 3.0T scanners.