In a study from 2006 to 2007, it was found that MRI can be used to measure the thickness of the optic nerve. If there is a loss of nerve fiber (optic atrophy), this becomes visible on MRI examination as a decrease in the diameter of the optic nerve thickness. This method using the 3T MRI proved to be an extremely sensitive and non-invasive method, which makes it possible to assess the condition of the optic nerve in a short examination time, especially in glaucoma patients.
General information
Magnetic resonance imaging (MRI) is a modern imaging technique that is used in ophthalmology and other fields. The examination by means of MRI makes use of the so-called nuclear spin, which means that each atomic nucleus rotates on its own axis and thus becomes a weak magnet. In magnetic resonance imaging, a strong magnet is used to bring the hydrogen atoms of the body, whose axes otherwise point in different directions, into a parallel arrangement.
Then radio waves are emitted which disturb the hydrogen atoms in such a way that their axial directions are changed. After switching off the radio waves, the hydrogen atoms jump back into their original parallel position and emit radio waves themselves, which are then recorded by the MRI machine. A sectional image is then calculated from this data for the respective plane.
In principle, therefore, only the density of the hydrogen atoms is measured, which means that the anatomical structures in the body, and especially the soft tissue, can be clearly depicted by the MRI. Magnetic resonance imaging (MRI) is very well suited for an accurate assessment of structural changes in the eye and eye socket, as it allows an exact differentiation between different tissues and substances. The procedure is used, among other things, to diagnose tumors and inflammation.
The size of structures, such as the thickness of the outer eye muscles, is then measured. This can be important in the case of muscle inflammation or inflammatory swelling of the eye sockets (endocrine orbitopathy, exophthalmos) and can be groundbreaking in the diagnosis. Especially in the case of an inflammation of the optic nerve (neuritis nervi optici, retrobulbar neuritis), the examination of a possible optic atrophy by means of MRI is of particular importance.
