MRI of the eye orbits and optic nerves: what shows?
The ability to see provides a sophisticated visual system beyond the eye, but also contains other links leading to the responsible centers of the brain. Visual inspection is available only the outer part of the eye, the eyelids and conjunctiva, the other parts of the system are securely hidden the skull bones that form the orbit. An important place in the diagnosis of diseases of the visual system is an MRI of the eye orbits.
Part of the visual system, except the eyeballs, which themselves have a complex structure, composed of the optic nerves are crossed, they form the optic tract, the muscles providing eye support and movement, eyelids, retrobulbar adipose tissue (pillow eyes). In addition to these components the normal functioning of the visual analyzer to provide a second, third, fourth, and sixth cranial nerves.
How to prepare for the procedure?
Eye orbit MRI requires no special preparation. You need to think about the clothes: it should not contain metal parts, and leave at home jewelry, watches, dentures and plates.
What diseases of the visual system allows to identify the study?
The accuracy of the method allows to detect virtually any disease of the visual system in different stages of development.
- Inflammatory processes in the cavity of the eyeball, the retina, optic nerve, eye muscles, and retrobulbar space.
- Cancer, their prevalence in the surrounding tissue.
- The degree of damage of injuries.
- Abscesses in the retrobulbar region and oculomotor muscles.
- Degenerative changes and atrophy of the optic nerve.
- A retinal detachment.
- Destructive processes of the vitreous and retina.
MRI of the orbits allows to establish an accurate diagnosis, if the patient complains of pain in the eye, or one eye swells, or the person is rapidly losing vision, the ophthalmologist is unable to detect pathological changes during a standard survey. Magnetic resonance imaging can also show the work of the body in real time and record the results on electronic media.
- MRI of the eye orbits is not carried out when the patient has metal implants and external structures, as they can heat up and shift under the influence of the electromagnetic field. It is possible to analyze if the metal structures and implants are made from inert to the electromagnetic field of alloys, such as titanium. However, even inert metals, located in the head region of the patient, can distort the result of the study, so you must inform your doctor about them before starting the research, since modern devices allow, in this case, to change the settings.
- Electronic implanted devices such as artificial pacemakers are an absolute contraindication to MRI of the orbits.
- Claustrophobia and other mental and somatic diseases, which do not allow the patient to be motionless in a confined space within thirty minutes.
- Weight more than one hundred and thirty pounds. A patient will not fit in the machine. The problem with obesity and claustrophobia is solved by the use of appliances with open chamber.
- When performing MRI of the eye orbits with contrast contraindications are allergic reactions and hypersensitivity to gadolinium salts. Do not conduct a contrast examination and patients with serious kidney disease, impairing the excretion of contrast from the body.
Interpretation of the results is conducted by the radiologist that performed the study, concluding with a description of the surveyed structures and diagnosis the patient receives an. Also the patient is given a film with successive image slices of the eye orbits, which are performed in increments of five (and sometimes two) of a millimeter. Currently image the patient are also on electronic media (disk, flash card).
Regardless of the conclusions of the radiologist, an ophthalmologist can interpret the result themselves, having studied the pictures. Evaluation of a physician is important, as it can correlate the photographs with the results of other studies and complaints of the patient.