X-ray signs of injuries and diseases of the organ of vision

Fractures of the walls and edges of the orbit are easily identified using survey and targeted radiographs. A fracture of the lower wall is accompanied by darkening of the maxillary sinus due to hemorrhage into it. If the orbital fissure penetrates the paranasal sinus, air bubbles in the orbit (orbital emphysema) may be detected. In all unclear cases, for example, with narrow cracks in the walls of the orbit, CT helps.

The injury may be accompanied by the penetration of foreign bodies into the eye socket and the eyeball. Metal bodies larger than 0.5 mm are easily recognized on radiographs. Very small and low-contrast foreign bodies are detected using a special technique - the so-called skeleton-free eye pictures. They are made on small films inserted after anesthesia into the conjunctival sac under the eyeball. The picture shows an image of the anterior part of the eye without the imposition of the shadow of bone elements. In order to accurately localize the foreign body in the eye, a Komberg-Baltin prosthesis is applied to the surface of the eyeball. Pictures with the prosthesis are taken in direct and lateral projections from a distance of 60 cm. The resulting pictures are analyzed using special diagrams applied to a transparent celluloid film, and the meridian of the eye on which the foreign body is located and its distance from the plane of the limbus in millimeters are determined.

Echophthalmoscopy and computed tomography have significantly facilitated the search and precise localization of foreign bodies in the orbit and eyeball. Ultrasound diagnostics of intraocular fragments is based on the detection of the so-called fragment echo signal - a short pulse on a one-dimensional echogram. The location of this peak on the isoline is used to judge the localization of the foreign body - in the anterior chamber of the eye, inside the lens, in the vitreous body or on the fundus. An important sign of the echo signal, indicating its fragment nature, is the disappearance of the peak with the slightest change in the direction of the biolocation axis. Under favorable conditions, modern ultrasound devices can detect fragments with a diameter of 0.2-0.3 mm.

To plan the extraction of a foreign body, it is important to know its magnetic properties. During echography, an electromagnet is turned on. If the shape and size of the "fragment" echo signal do not change, then it is assumed that the fragment is amagnetic or that there are pronounced scars around it that prevent its displacement.

Most diseases involving the eyeball are diagnosed using direct ophthalmoscopy and ultrasound. Computer or magnetic resonance imaging is used primarily to identify lesions of the posterior orbit and to detect their intracranial extension. Tomograms are very useful for determining the volume of the eyeball and thickening of the optic nerve in neuritis.

Ultrasound and MRI are widely used for opacities of the optical media of the eye in cases where direct ophthalmoscopy is ineffective. For example, in the case of corneal leukomas, echography allows determining its thickness, as well as the position and thickness of the lens, which is necessary when choosing a surgical technique for keratoplasty and keratoprosthetics. In the case of membranous cataract, i.e. partial or complete opacification of the substance or capsule of the lens, a single "lens" echo signal is detected, indicating the presence of a membranous structure between the vitreous body and the cornea. Immature cataract is accompanied by the appearance of additional small echo signals between two lens signals on a one-dimensional echogram.

When the vitreous body is clouded, the degree of its acoustic heterogeneity can be determined. A typical picture is given by focal endophthalmitis - a severe eye disease accompanied by loss of transparency of the vitreous body.

In case of eye tumors, ultrasound examination makes it possible to determine the exact localization and area of the lesion, its growth into adjacent membranes and the retrobulbar space, the presence of small foci of necrosis, hemorrhage, and calcification in the neoplasm. All this in some cases makes it possible to clarify the nature of the tumor.

X-ray examinations are necessary in case of pathological protrusion of the eyeball from the orbit - exophthalmos. When analyzing skull X-rays, so-called false exophthalmos is immediately excluded - protrusion of the eyeball with congenital asymmetry of the bones of the facial skull. The nature of true exophthalmos is established by sonography, CT or MRI. These methods allow detecting a hematoma due to trauma, a cyst or tumor in the tissues of the orbit or growing from a neighboring area, a cerebral hernia in the orbital cavity or the spread of an inflammatory process from the cells of the ethmoid labyrinth to the latter.

Some patients have pulsating exophthalmos. It may be a manifestation of an aneurysm of the ophthalmic artery, arterial hemangioma, or damage to the carotid-venous junction. If it is not possible to perform CT or MR angiography, then carotid angiography (X-ray contrast study of the carotid artery and its branches) is performed. A variant is intermittent exophthalmos, which occurs with varicose veins of the orbit. In this case, angiographic methods are of decisive importance in diagnostics - CT, MR angiography or venography of the orbit.

Exophthalmos sometimes develops as a result of endocrine disorders, in particular, thyrotoxicosis. In these cases, it is associated with an increase in extraocular muscles (especially the medial rectus muscle), which is clearly recorded on CT and MRI scans. They also allow one to detect exophthalmos caused by fat accumulation in the orbital cavity. The diagram shows an approximate examination tactic carried out to determine the causes of exophthalmos. Two radiation techniques have been developed for examining the lacrimal ducts: X-ray and radionuclide dacryocystography. In both cases, after anesthesia of the conjunctiva with 0.25% dicaine solution, a 1-2-gram syringe is used through a thin blunt needle to inject a contrast agent into the upper or lower lacrimal punctum. With X-ray dacryocystography, a radiopaque agent is injected (recently, digital radiography has become the method of choice, allowing one to obtain an image of the lacrimal ducts without superimposing bone elements).