echo echo, echo + entsefalogra-
fiya; a synonym an ultrasonic encephalography) — a method of a research of a brain by means of ultrasound. Soft tissues and bones of a skull, tissue of a brain have various acoustic resistance and reflect ultrasound in different degree (see), as is used in the diagnostic purposes (see. Ultrasonic diagnosis). For the first time the technique of definition of provision of the ultrasonic signals which are reflected from median structures of a brain — a so-called median echo (M-echo), was offered in 1956^-1958 by the Swedish scientist L. Leksell.
AA. allows to reveal volume damages of a brain (tumors, hematomas, abscesses, foreign bodys, etc.), hydrocephaly, intracerebral hypertensia, wet brain. The method has practically no contraindications and can be applied in all cases when it is possible to provide a dense prileganiye of the ultrasonic sensor (probe) to head skin.
One-dimensional E. carry out by means of the ultrasonic encephalographs in particular released by the domestic industry of a stationary ekhoentsefalograf of «EHO-11» (its modification «ESM-01») and figurative — «EHO-12». Special training of the patient for carrying out
a research is not required. AA. usually carry out in position of the patient lying, but its carrying out is possible and in position of the patient sitting. The ultrasonic sensor, working surface to-rogo it is processed (for ensuring acoustic contact) a liquid paraffin, consistently put to various sites of the head which are also previously processed by a liquid paraffin. The ultrasonic signals transformed to electric impulses appear on the screen of the device in the form of a curve — an ultrasonic encephalogram (an ekhoentsef of a logramma)» to-ruyu photograph and analyze. Optimal conditions for receiving an echo signal are created at an arrangement of the sensor on a side surface of the head 4 — 5 cm higher than outside acoustical pass on the biaurikulyarny line passing through parietal area.
On an ekhoentsefalogramma (fig.,/) the initial complex (IC), the final complex (FC), a median echo (M) and impulses from various not median structures of a brain (ES) distinguish. Initial complex — the site of an ekhoentsefalogramma consisting of a generating impulse and echo signals from soft tissues of the head, bones of a skull and superficial
Fig. The diagrammatic representation ekhoentsefalogramm is normal (X) and at volume education in the right cerebral hemisphere (1 l): above — a frontal section of the head with the ultrasonic sensors located in temporal areas (And, B); below ekhoentsefalogramma are placed (And — right, B — left); CC — median structures (the third ventricle of a brain), M — an echo signal from median structures of a brain (M-echo), ES — an echo signal from various not median structures of a brain, the Tax Code — an initial complex, K K — a final complex; the distance is normal and on the ekhoentsefalogramma received at installation of the sensor on the right it is equal to distance on the curve received at installation of the sensor at the left, at pathology (volume education in the right cerebral hemisphere is shaded) the distance and on the right (upper) curve is increased at the expense of the shift of median structures of a brain, the direction of shift of the M-echo is opposite to localization of the pathological center.
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structures of a brain. The final complex forms from echo signals from an inner surface of bones of a skull, soft tissues of the head, borders the head — air undressed; the most constant is the echo signal from an inner surface of bones of a skull. Other elements of a final complex appear only at full passing of ultrasound through bones of a skull.
Between two main complexes of an ekhoentsefalogramma there is a large number of the impulses caused by reflection of ultrasound from various structures of a brain. A part of impulses is changeable, another — is rather stable, and a number of impulses appears only in the presence patol, process in a brain. The echo signal from median structures of a brain (the third ventricle, a pinus, a transparent partition, a falx cerebri, etc.) appears the most constant. This echo signal (M-echo) dominates over impulses from other structures, the basis is wider than it, sometimes it consists of two or several impulses.
Normal the M-echo is located on the centerline of a brain, and admissible shift it shall not exceed 1 — 2 mm. Shift of the M-echo more than on 2 mm indicates existence of volume process in a cerebral hemisphere opposite to the direction of shift (fig., II). Other diagnostic criteria are various number of echo signals at a research of the right and left half of the head (an intersemicircle-naya asymmetry), increase in distance between echo signals from sidewalls of the third cerebral cavity (hydrocephaly) and some other. Also record of a pulsation of echo signals from walls of arteries — an ekhopulsografiya is used.
In recent years it is developed two-dimensional E. Basic feature of a method is gradual movement of the ultrasonic probe on the surface of the head. On the screen of an ekhoentsefalograf arise the image of a horizontal cut of the head received through movement of the ultrasonic probe, and also the image patol. the formations of a brain which are localized at this level. However various conditions for passing of ultrasound in different sites of the head cause a set of the artifacts which are sharply reducing efficiency of diagnosis by means of a two-dimensional ekhoentsefalogra-fiya.
Bibliography: Bogolepov N. K., etc. Clinical ekhoentsefalografiya, M., 1973; Grechko V. E. Ultrasonic ekhotopografiya of a brain, Zhurn. neuropath, and psikhiat., t. 67, No. 12, page 1783, 1967; Grechko V. E. and it is sharp in G. I. Issledovaniye of echo signals
and ekhopulsation of vertebral arteries the ultrasonic devices «EHO-11» and «UDA-872», It is new. medical tekhn., century 2, page 73, 1975; L e k s e 1 1 L. Echo-encephalogra-phy, detection of intracranial complications following head injury, Acta chir. scand., y. 110, p. 301, 1956. Century of E. Grechko.