Echoencephalography (ECHO-EG): what is it and what it’s for?
Echoencephalography (Echo-EG) – ultrasound examination of brain tissue. The technique allows to estimate intracranial pressure, to reveal volumetric processes that cause displacement of brain structures, but does not allow to differentiate detected pathological formations. It is usually used at the stage of primary diagnosis, precedes other, more accurate methods of investigation (CT, MRI). It is carried out without preliminary preparation, has no contraindications. Echoencephalography includes the actual scanning and calculation, allowing to determine the internal size of the skull, the presence of displacement of the brain structures and signs of intracranial hypertension.
Indications for Echoencephalography
The technique is prescribed by the neurologist at the stage of primary diagnosis with complaints of a neurological nature: headaches, a feeling of pressure on the eyes, dizziness, nausea without eating, “cut-off” or loss of consciousness, noise in the head, shortness of air, memory and attention impairment, decrease in efficiency, etc.
Echo-EG is indicated if there is a suspicion of an increase in intracranial pressure or for its control measurement. Recently, in clinical neurology, Echo-EG is increasingly used as a method of preliminary examination, preceding MRI or CT of the brain.
Echoencephalography can be used to detect hydrocephalus, cerebral edema, volumetric formations in the cranial cavity (hematomas, tumors, foreign bodies, abscesses, cysts) with the inaccessibility of more modern diagnostic techniques (MRI, MSCT and CT). Ultrasound diagnosis is considered harmless, so the Echo-EG has no contraindications.
Echoencephalography: Method of conducting
Preparation is not required. Before starting the procedure, it is necessary to remove from the head foreign objects that can interfere with Echo-EG (hair clips, hoops, etc.).
Manipulation is performed by installing an ultrasonic sensor on the scalp in certain places. These areas are pre-lubricated with a contact gel or vaseline oil to avoid interference.
As a rule, the following sensor positions are applied from each side: above the external ear canal, on the temple – at the outer edge of the eyebrow, behind the ear – 4-5 cm behind it. Ultrasonic signals sent by the sensor are reflected differently from the skin, bones of the skull and brain tissue. The reflected signals are picked up by the sensor and transmitted to the device, which displays them on the screen in the form of echo-complexes resembling the electrocardiogram teeth.
During the Echo-EG, the doctor measures the distances between the initial, middle and final echo complexes. The length of the segment between the initial and final complexes gives information on the internal size of the skull. Comparison of segments from the initial and final complex to the middle one allows one to judge the displacement of brain structures in one direction or another.
The difference in the length of these segments is called the displacement of the middle M-echo and normally does not exceed 2 mm. In the presence of large volumetric processes, the brain tissues are displaced, the symmetry of the recorded signals disappears, and the change in this indicator is fixed on the Echo-EG.
Additional echo complexes can be registered. The measurements are carried out by alternately setting the sensor in each of the three positions to the right and left.
In the process of echoencephalography, pulsation of the median echosignal is investigated, determining its amplitude in percent. This is necessary to evaluate intracranial pressure. It is believed that the normal intracranial pressure corresponds to the amplitude of pulsation of the median Echo-EG signal in 25%.
If it varies between 25-50%, this is a sign of mild intracranial hypertension, 50-75% indicate a moderate, more than 75% – a marked increase in intracranial pressure. In severe cases, there is no ripple. Echo-EG usually lasts no more than 10-15 minutes.
A separate type of echoencephalography is the two-dimensional Echo-EG, in which the doctor gradually moves the sensor, sliding it over the surface of the head. This allows you to get an image of a horizontal “cut” along the sensor motion line and visualize the formations located at this level.
When carrying out a two-dimensional echoencephalography on an image, artifacts that complicate diagnostics and reduce its reliability are often recorded.
Echoencephalography (brain ultrasound) cost in the United States
Echoencephalography is an inexpensive, safe brain study performed in many specialized and multidisciplinary clinics in the capital, equipped with special equipment. The most significant effect on the price of echoencephalography in United States is provided by the form of ownership of the medical organization that conducts this diagnostic procedure.
The cost of manipulation in the state polyclinics is usually more accessible, the negative aspect when appealing to such institutions is a possible long waiting period. In private medical centers, the price of Echo-EG may vary depending on the qualifications of the specialist and the availability of additional services.