Echoencephalography( EchoEg) - Causes, symptoms and treatment. MF.

Echoencephalography( EchoEG) is a noninvasive method of brain examination by ultrasound( ultrasound at a frequency of 0.5 to 15 MHz / s).Sound waves of this frequency have the ability to penetrate the tissues of the body and are reflected from all surfaces lying on the border of tissues of different composition and density( soft covers of the head, skull bones, brain membranes, brain substance, cerebrospinal fluid, blood).Reflective structures can be pathological formations( foci of crushing, foreign bodies, abscesses, cysts, hematomas, etc.).

Echoencephalography( EchoEg)

In children under 1.5 years of age, the fontanelle, through which the EchoEG study is performed, allows all brain structures to be assessed. In adults, echoencephalography is used primarily to detect voluminous brain formations in the following pathologies:

headache,
dizziness,
head trauma,
diffuse and local edema of the brain,
intracranial hematomas,
abscesses,
brain tumors,
intracranial hypertension,
hydrocephalus,
inflammatory diseases of the brain,
other cerebral diseases.

Echoencephalography( EhoEG) used to diagnose diseases:

cerebral ischemia, stroke
concussion, contusion
brain vertebrobasilar insufficiency
vascular dystonia( VVD)
disorders of cerebral blood flow
Headache
Dizziness
Noise in
ears Intracranial pressure
Injury neck
Encephalopathy
Parkinson's disease
Pituitary adenoma

Echo of the study

The examination is carried out mainly prone, in sequence withravoy, then the left side surface of the head from the forehead to the occipital region. The most constant impulse is the echo signal reflected from the middle structures of the brain( transparent septum, third ventricle, epiphysis), called "M-echo".

No contraindications.

Echoencephalography( EchoEg) deciphering the results

Echoencephalography( EchoEG) is based on the recording of ultrasound reflected from the boundaries of intracranial formations and media with different acoustic resistance( skull bones, brain substance, blood, CSF).Neurological practice was introduced by the Swedish doctor L. Leksell( L. Leksell, 1956).The echoencephalograph designed for this device generates an exciting generator pulse and provides the possibility of registering a reflected echo on the oscilloscope screen( echoencephaloscopy), which can be recorded in the recording( proper echoencephalography).

In the process of echoencephalography, the echolocation mode( emission method) can be used. At the same time, the same piezoelectric sensor is used to radiate and receive ultrasound reflected from the brain structures, and under the transmission localization regime the signal emitted from one piezoelectric sensor is received by another piezoelectric element. The echoencephalogram obtained in this case consists of an initial complex - an echo signal from the soft tissues of the head and cranial bones located directly under the ultrasound probe;echoes from various intracerebral structures and the final complex - echoes from the inner surface of the bones of the skull and soft tissues of the opposite side.

From the echoes from the intracerebral structures, the most important signal is the signal with the largest amplitude-the M-echo( the first diagnostic criterion of Lexell) reflected from the medial structures of the brain located in the sagittal plane( the third ventricle and its walls, the transparent septum, the large crescent, the hemispheric fissure, epiphysis);located
on the sides of the M-echo additional signals of a significantly smaller amplitude( Lexk's second diagnostic criterion) normally are a reflection from the walls of the lateral ventricles.

Normally, the structures forming the M-echo are located strictly in the sagittal plane and are at the same distance from the symmetrical points of the right and left sides of the head, so on the echoencephalogram in the absence of pathology, the M-echo signal is equally distant from the initial and final complexes.

Deviation of the median M-echo by more than 2 mm to either side should be considered as a manifestation of pathology. The most informative indicator of the presence in the supratentorial space of a voluminous pathological focus( tumor, abscess, local edema of the brain, intracranial hematoma) is the displacement of the middle M-echo in the direction opposite to the location of this focus. The appearance on the EEG of a large number of reflected signals between the initial complex and the M-echo signal indicates a probable presence of cerebral edema. If the median M-echo signal consists of two pulses or has jagged vertices and a wide base, this indicates an expansion of the third ventricle of the brain.

Different number of echoes of the left and right hemispheres of the brain is considered as ultrasonic interhemispheric asymmetry, the cause of which can be a pathological focus of various origin in one or both hemispheres of the brain. Additional signals from pathological
structures located in the cranial cavity( Lexx's third diagnostic criterion) indicate the presence of tissues with different density in the cranial cavity. They can be of different origin and therefore they should not be overestimated when determining the nature of the underlying causes of their
.

With concussion of the brain, the displacement of the median structures in echoencephalography( EchoEG) does not exceed physiological abnormalities. In focal brain contusions, due to edema of the brain tissue, the M-echo signal shift during echoencephalography( EchoEG) towards the intact hemisphere can be 2-5 mm with a gradual increase to the 4th day and tends to regress for 1-3ned. Peak-like signals can be detected in the area of ​​the contusion on the echoencephalography( EchoEG), due to the reflection of ultrasound from small focal hemorrhages.

Especially important is the echoencephalography( EchoEG) acquired by compression of the brain. Possible early diagnosis of supratentorial membrane hematomas, in which the displacement of the median brain structures toward the healthy hemisphere appears already in the first hours after CCT and tends to increase to 6-15 mm. Often, with echoencephalography( EchoEG), direct reflection of ultrasonic signals from the border between the hematoma and the brain substance or adjacent brain envelopes is observed. When trying to echolocation on the side of the location of the hematoma, the signal reflected from its boundary falls into the initial "dead zone" and therefore the echolocation of the hematoma is possible only from the opposite side.

The hematoma echo in echoencephalography( EchoEG) is a high-amplitude non-pulsating signal that is recorded between pulsating low-amplitude signals from the walls of the lateral ventricles and the final complex( reflection from the opposite wall sensor of the skull).It should be borne in mind that in case of damage and edema of soft skull covers, echoencephalography( EchoEG) reveals a significant difference in the distance to the final complexes, which often leads to errors when interpreting the results of the study. In these cases, one should focus not on the initial, but on the final complex of signals from the inner surface of the bone to the M-echo, and then determine the magnitude of its displacement according to known formulas.

With bilateral hemispherical hematomas, with hematomas of the posterior cranial fossa, as well as in the lobular and basal localization of volumetric hemorrhages, the diagnostic value of the echoencephalography( EchoEG) method is reduced, as the determination of the displacement of the midline structures of the brain loses its decisive importance. In these cases, the diagnostic capabilities of the multi-axis one-dimensional echoencephalography( EchoEG), in which the "dead" space is eliminated by using special attachments and the angle of ultrasound input is varied within wide limits.

When observing the dynamics of traumatic brain disease, the size of the ventricular system is determined( mainly by the magnitude of the ventricular index) and the magnitude of their pulsation( as a percentage of the M-echo signal).The increase in pulsation usually correlates with the increase in intracranial hypertension. Normalization of pulsation and the size of the ventricular system with echoencephalography( EchoEG) is an indicator of a favorable course of traumatic brain disease. Complete absence of pulsation in echoencephalography( EchoEG) is an additional criterion indicating the stopping of cerebral circulation in cases of terminal coma.

In recent years, methods have been developed for multi-axis Echo and echo- pulsography, which makes it possible to evaluate the shape and amplitude of pulsating echoes from the vessels and walls of the ventricular system, to determine the degree of vascular dislocation and to judge the severity of intracranial hypertension.

The main advantage of the method is that it helps to diagnose diseases leading to displacement of intracranial structures from the midline of the brain. Currently, echoencephalography is increasingly being replaced by computed tomography( CT) and nuclear magnetic resonance( NMR).