From Big Medical Encyclopedia


of KA — recognition of pathological changes of separate bodies and systems by means of methods of distantny ultrasonic investigation.

At. is founded on the principle of echolocation (radiation of the probing impulse of ultrasound and reception of the signals reflected from interfaces of the fabric environments having various acoustic properties). Methods U. supplement radiodiagnosis (see), a computer tomography (see the Tomography computer) and radio isotope diagnosis (see) at recognition of diseases, differential di

the agnostic, overseeing with dynamics patol. process and assessment of results of treatment.

High resolving power, possibility of carrying out repeated researches, safety of methods U. and in this regard lack of any contraindications promoted that At. was widely adopted in clinic.

For the first time ultrasound (see) with the diagnostic purpose it was used in 1942 by the Austrian neuropathologist R. Dussik at recognition of tumors of a brain. In 1951 — 1958 Wilde (T. Wild) and D. Howry with employees conducted successful researches of parenchymatous human organs by means of ultrasound. The significant contribution in At. were brought by scientists and our country.

Waves of ultrasound extend in the homogeneous carrying-out elastic medium rectilinearly. Their gradual attenuation depends as on acoustic properties of the environment (so-called acoustic resistance, or an acoustic impedance), and on the wavelength (frequency of ultrasonic fluctuations). If on the way of ultrasonic radiation the interface of two environments meets various acoustic properties, then it leads to partial reflection of ultrasonic waves on border of these of Wednesdays. The distinction in the acoustic resistance of two environments is more considerable, the most part of ultrasonic radiation is reflected. On limit of the section of such environments as muscular tissue — the bone, is reflected apprx. 30 — 40% of a radiation energy since the acoustic resistance (acoustic density) of a bone tissue is much higher, than soft tissues, and on border soft tissues — gas or liquid — gas reflection is almost full since the gaseous fluid does not carry out ultrasonic waves. The last explains inefficiency of use of ultrasound for a research of the bodies containing gas, napr, lungs, intestines.

There are several main methods of an ekhografiya — registration of the echo signal sent by the converter of ultrasound through a body surface to depth of fabrics. The one-dimensional method, or an A-method (English amplitude amplitude), consists in registration on the screen of an oscillograph of the reflected signal in the form of peak on a straight line (isoline) of development of an electron beam (fig. 1). At the same time height (amplitude) of peak is proportional to intensity of the reflected signal and, therefore, a difference between values of acoustic resistance of two environments.

On distance between a mark of the initial probing ultrasonic signal and peak of echo signals it is possible to judge depth of an arrangement of limit of the section of two environments. At a one-dimensional method of a research the sensor of the echolocator is installed on a body surface in one

Fig. 1. The echogram removed by means of the A-method: 1 — the moment of radiation of an acoustic impulse; 2 — a complex of echo signals from the studied acoustically heterogeneous structures.

situation, and echo signals allow to define distance to the objects reflecting ultrasound only in one set direction of sounding.

The two-dimensional method, or V-method (English bright brightness), is based on the principle of scanning of an object by an ultrasonic beam (an ultrasonic tomography, an ekhotomografiya), to-rogo ultrasonic the beam moves to time on the surface of the explored area of a body. The signals reflected from acoustically heterogeneous structures will be transformed on the screen of the television display to the shining points creating the space two-dimensional image. Intensity of brightness of a luminescence on the ordinary screen depends on intensity of an echo signal a little. During the use of the electron-beam tube having the screen with a gray scale. brightness of a point depends on intensity of an echo signal, i.e. on the acoustic resistance of the studied fabrics. The image in this case is reproduced in various shades of the gray tone reflecting acoustic structure of the scanned layer of a body of the person (a method of «a gray scale»).

Depending on the nature of movement of the scanning beam over the studied object distinguish linear (parallel movement), sector (when the tilt angle of the scanning beam changes), convergent (the beam moves on an arch) scanning. Besides, it is possible to carry out the difficult scanning consisting in a combination of these ways of a research. If scanning is made with a frequency of 16 — 30 images of (shots) of 1 sec., there is a cinema effect allowing to register the movements of the studied objects (e.g., valves of heart, an interventricular partition, abdominal organs)

in their natural temporary mode. This method U. carries the name of an ekhografiya in real time.

In cardiology at At. of fast-moving objects (valves of heart, a wall of his cavities) use also the M-method (English motion the movement) which is option of an A-method with development of a one-dimensional echo signal in time (see Ekhokar-d of yogas a raffia).

One of kinds of a two-dimensional ekhografiya is the combined method U., in Krom ultrasonic scanning is combined with the definition of peripheral speed of a blood-groove based on Doppler's effect (a dopplerosonografiya, a dopplerotakhografiya, an ultrasonic floumetriya). At this method of a research the echo signals reflected from structures of the scanned large vessels (carotid arteries, arteries and veins of extremities, etc.), and also changes of frequency of the ultrasonic signals reflected from the elements of blood moving in vessels are registered. At continuous echolocation of a moving object the signal reflected from it changes on frequency at a size proportional to the speed of the movement of the studied object in the direction to the sensor having the special converter. The devices of pulse and Doppler type created in recent years allow to register the speed of a blood-groove in deeply located main vessels (an aorta, the lower vena cava, vessels of kidneys, etc.). The method is used for identification of a zone of thrombosis or a prelum of a vessel, and also recognition of an obliterating endarteritis.

In ultrasonic diagnostic units various parameters are registered: reflection, absorption and dispersion of ultrasonic waves, change of rate of propagation and spectral structure of radiation, etc. The resolving power of the modern ultrasonic scanning equipment determined by the minimum distance between two objects at Krom they on the screen differ as separate structures, makes

1 — 2 mm. Usually in devices for At. use ultrasonic radiation in the range of 0,5 — 15 MHz. At the same time to more low frequencies there corresponds the largest penetration depth of ultrasound which is required, e.g., in obstetrics for definition of provision of a fruit or at diagnosis of damages of a brain. Devices with high frequency of ultrasonic radiation apply at a research of the small, located close to a body surface bodies and anatomic struk-

Rns. 2. The schematic diagram of an ekhoyekopiya with one-dimensional indication of an echo signal (A-method): 1 — the ultrasonic converter; 2 — an object of a research; 3 — the field of ultrasonic radiation; 4 — the generator; 5 — the amplifier; 6 — the screen of an oscillograph. Shooters specified flow direction of electric impulses from the generator to the converter of ultrasound and from the converter to the amplifier of the registered signals.

a tour — eyes, nek-ry hemadens, vessels, etc.

Ultrasonic examination of bodies and anatomical structures carry out by means of ultrasonic converters of various design.

By the principle of action devices for At. divide into the ekhoimpulsny, intended for definition provisions of anatomical structures (ultrasonic or ekholokaliza-Torahs, visualizers, indicators, measuring instruments); devices, in to-rykh Doppler's effect, applied to definition of kinematic characteristics of nek-ry bodies, and also devices of the combined, pulse and Doppler type is used.

To devices of the first type ekholokalizator treat with one-dimensional indication of an echo signal (fig. 2). The ultrasonic converter of these devices excited from the generator by short electric impulses radiates impulses of ultrasound, to-rye, passing through a body of the patient, are reflected from acoustically heterogeneous objects, are registered the same converter, amplify and visualized on the screen of an oscilloscope. At the known rate of propagation of a sound among an interval of the oscillogram from the beginning of radiation of an acoustic impulse to a complex of the reflected echo signals characterizes distance from a body surface to the studied object. Work at this principle an ekhoentsefa

of a loskopa — devices for At. of volume formations of a brain, with the help to-rykh define a difference of distances from the surface of the head to its median, intracranial structures (see Ekhoentsefalografiya). One-dimensional indication is used in ekhooftalmoskopa, to-rye apply at diagnosis of diseases and injuries of an eye and eye-socket, and also at measurement by means of ultrasound of optical length of an eye (echo-okulometriya). The method of one-dimensional indication is auxiliary in the majority of devices with two-dimensional visualization (indication). In all devices with two-dimensional indication the registered echo signal moves on the modulator of brightness of an electron-beam tube. It during the scanning by the sensor on a body surface of a pas of a tsiyent on the screen of an oscillograph

is resulted by a two-dimensional picture light an ekhootmetok, forming the image of body (V-method). There are three kinds of the scanners working in such mode: scanners with

linear, sector and difficult

types of scanning. The ultrasonic converter contains piezoelements in the first case, raspolo

zhenny in a row and usually serially switched with pomo

I sew (fig. 3) electronic devices on radiation or on reception. At linear scanning on the screen of the monitor the two-dimensional image, cross ekhosrez bodies of the patient forkhmirutsya. х^кие scanners found the greatest application in obstetrics, a giekologiya, oncology, at issle-

for Fig. 3. The schematic diagram of the scanner with linear scanning: 1 — the manual

probe (converter) with three piezosensors; 2 — an object of a research; 3 — a bunch of ultrasonic waves; 4 — the direction of movement of the ultrasonic field;

5 — the cable connecting the manual probe of management of echolocation and obtaining the image to the device for ultrasonic diagnosis. Shooters specified flow direction of electric impulses from the generator to the converter of ultrasound and from the converter to the amplifier of the registered signals. The dotted line designated the maximum zone of a research, to-ruyu covers the converter at consecutive switching of piezosensors to radiation or to reception ekhosignalon.

giving of internals: on

the check, a liver, a spleen, a uterus, a gall bladder, etc.

Devices with two-dimensional indication are sector scanners, to-rye are widely used in cardiology. In such devices development of light marks of various brightness from echo signals is carried out along a fan bunch of ultrasound. Advantage the sector

the leg of scanning is a possibility of a research of bodies,

in particular hearts, through narrow acoustically transparent areas between edges (see the Echocardiography).

Linear and sector scanners can work with two-dimensional indication in real time that plays a large role during the obtaining images of moving bodies (e.g., hearts) or a fruit. In gynecology and oncology often use the scanner with difficult scanning, in Krom the ultrasonic converter is fixed on a hinged bracket that gives the chance to the operator to move it in a certain plane. The provision of a beam with the brightness ekhootmetka on the screen of such scanner strictly corresponds to the direction of the ultrasonic field in a body of the patient. Moving the sensor with the converter on a body surface of the patient, the operator «draws» the image of the studied body on the screen of the device. Despite impossibility of visualization of mobile structures, advantage of the scanner with difficult scanning consists in an opportunity to observe at the same time on the screen of the image of several bodies or extensive area of a body.

The special device of one-dimensional indication is the ekhokardi-ograf working by the principle of the M-method. Registered after reflection from structures of heart (e.g., valves) the echo signal after strengthening moves on the modulator of brightness, at the same time temporary development at the same time registers. During cordial reductions position of the reflecting borders, in particular valves of heart (see Valjvulografiya), aortas, etc. changes. Received on the screen of an oscilloscope or on paper of an ekhokardiogramma allow to judge features of a structure of heart and dynamics of its reductions. Registration of a signal of O K of for correlation of an ekhokardiogramma with phases of cordial reduction, and also in some cases and other data of biometrics is provided in all ekhokardiograf (e.g., registration of the phonocardiogram).

The equipment for At., the principle of action a cut is founded on Doppler's effect, is applied at a research of heart, a fruit, blood vessels, with its help it is possible to investigate passability of peripheral vessels, speed and the direction of a blood-groove in them. Special Doppler visualizers of vessels allow to receive ultrasonic «card» of vessels of a body, and spectrum analyzers of Doppler signals — to reveal various patol. changes of cardiovascular system. Recently there were devices, in to-rykh the possibilities of ekholokatsionny devices and the equipment of Doppler type providing quantitative definition of characteristics of a blood-groove in the studied vessel are combined.

Usually a research at At. does not demand any special training of the patient. The research of abdominal organs is generally made in the morning on an empty stomach; researches of female generative organs, a prostate and a bladder carry out at the filled bladder. For the best contact of the ultrasonic sensor with a body surface skin before a research is oiled liquid or special gel.

Use of an ekhografiya allows to diagnose various volume educations with rather high precision. E.g., cysts (see the Cyst) on echograms usually have an appearance round or an oval form free from internal structures, i.e. ekhonegativny (not educating echo signals) with a smooth inner surface. The distant contour of cysts is defined more accurately, than front, and directly behind it there is a so-called enhancement effect. Tumors (see), especially small sizes, give the image of various acoustic density of a round or oval form, is frequent with uneven contours. At the big sizes of a tumor on an echogram increase and deformation of contours of body, change of its internal ekhostruktura comes to light. Sometimes in a tumor certain ekhonegativny sites of irregular shape — the centers of a necrosis or hemorrhage are found.

Abscesses (see Abscess) in most cases come to light as the round or containing liquid oval educations. They are homogeneous or have gentle internal inclusions. Walls of abscess can be smooth or uneven. Sometimes in an abscess cavity partitions or level of stratification of the liquid parts of contents of abscess having different density are visible. In the presence of dense pus in an abscess cavity he on ekhografichesky signs can remind a tumor. A distinguishing character of abscess is and and l and h and e re and to t and in N y x and z m e N to it and y in the fabrics surrounding it. Unlike abscesses of a hematoma (see the Hematoma) have irregular shape more often, partitions in them come to light not always and are thinner also less accurate.

R1spolzovaniye methods U. allows to obtain important diagnostic information on a condition of various bodies, naira, a liver, a pancreas, spleen, kidneys, a bladder, prostate, adrenal glands, a thyroid gland, etc.

Normal the parenchyma of a liver (see) reflects multiple echo signals of average intensity. At acute inflammatory diseases or heart failure with developments of stagnation there is an effect of increase in ultrasonic transparency of a liver. In early stages of cirrhosis (see Cirrhosis) the liver on echograms is increased, its back surface is looked through worse, than normal, in connection with existence of the centers of consolidation increase in a spleen, expansion of splenic and portal veins is noted. At the developed cirrhosis the liver on an echogram is reduced, in an abdominal cavity ascites comes to light. At the expressed ascites (see) almost all abdominal cavity is filled with liquid, intestines are raised to a front abdominal wall. At a small amount of ascitic liquid it is defined on echograms preferential in side departments of a stomach in the form of the small ekhonegativny zones located between a liver and a right kidney or on a back surface of the right hepatic lobe. Trace amount of liquid comes to light in a cavity of a small pelvis, behind a uterus or a bladder better. The tumor of a liver in most cases has an appearance of accurately outlined education differing on acoustic properties from normal tissue of a liver. Quite often directly around a tumor the rim of fabric of the lowered echogenicity comes to light. Metastasises of malignant tumors in a liver are defined in the form of round educations, to-rye depending on their histologic structure can be characterized by both high, and low acoustic resistance.

Tissue of a pancreas (see) on acoustic properties it is close to a parenchyma of a liver. The main reference point during the definition of an arrangement of a pancreas on an echogram is the splenic vein, edges passes ‘lengthways to the zayena of beliefs hiy p overkhnost of glands y. At acute pancreatitis (see) increase in acoustic

ii r about z r and and about with t and t to and N and p about d e in l at d internally y glands and increase in its sizes is observed h. At chronic pancreatitis reduction of the sizes of gland, roughness of its contour, and also increase in its acoustic resistance can be observed. Cysts of a pancreas come to light as ekhonegativny educations with equal contours. Tumors of a pancreas can also have an appearance of the educations which are almost completely deprived of internal structures, however unlike cysts at tumors roughness of a contour of education in most cases is defined. The minimum size of a cyst of a pancreas, edge can be revealed at an ekhografiya, makes apprx. 10 mm, and a tumor — apprx. 30 mm.

The spleen (see) normal comes to light on an echogram as formation of a semi-lunar form, almost homogeneous, containing much less than ekhopozitivny internal structures, than a parenchyma of a liver. At it is strong omegaliya (see) ultrasonic investigation allows to establish or exclude existence of tumors, cysts, hematomas or abscesses but to ekhografichesky signs, characteristic of them.

Ultrasonic investigation is applied at diagnosis of various malformations, damages and diseases of kidneys. At an aplasia of one of kidneys its image is not on an echogram, during the doubling of a kidney two separate groups of echo signals from chashechnolokhanochny structures come to light. The nonfunctioning kidney can remind on an echogram in a form normal, but the image of a pyelocaliceal complex at the same time does not come to light. Existence in a parenchyma of a kidney of multiple ekhonegativny zones of various form and the sizes testifies to a polycystosis (see Paule an ikistozny dysplasia of kidneys). At the same time increase in kidneys, disappearance of the image of a pyelocaliceal complex on an echogram is quite often noted. In case of a hydronephrosis (see) on cross section at an ekhotomografiya cup structures have round or S-obraz-nuyu, and on longitudinal section — an ovo-idny form. At the expressed hydronephrosis the kidney on an echogram has an appearance of a big cyst. Tumors of a kidney cause its increase; contours of a kidney become uneven, deformation, «amputation» or total disappearance of a pyelocaliceal complex of echo signals comes to light. Stones of kidneys have an appearance of the educations with the increased acoustic resistance located in a parenchyma of a kidney or in the field of its pyelocaliceal ekhokompleks; quite often behind them the acoustic shadow appears.

In urological practice At. apply also for the purpose of diagnosis of diseases of a bladder and a prostate. At a diverticulum of a bladder on echograms sacculate protrusion of one of walls of a bubble is noted. Tumors come to light as the formations of various sizes and average or small acoustic density connected with a wall of a bubble. Stones of a bladder have more dense structure in the acoustic relation and are displaced at change of position of a body of the patient. Flatness of its contour and uniformity of an internal ekhostruktu-ra is characteristic of adenoma of a prostate (see). At a prostate cancer (see) its deformation is observed, in a parenchyma sites of the increased acoustic density quite often come to light. At germination of a tumor in the next bodies disturbance of an integrity of the capsule of a prostate is noted.

Ultrasonic visualization of adrenal glands (see) it is possible not always. Their ultrasonic sounding is made as from a back, and a stomach. Normal adrenal glands on echograms have the triangular, cone-shaped or crescent shape. At tumors of adrenal glands their sizes increase. The minimum size of a tumor of an adrenal gland, edge can be diagnosed at an ekhografiya, makes 10 — 15 mm, however the educations exceeding 25 mm in the diameter come to light more often. To differentiate at At. various tumors of adrenal glands usually is not possible. In some cases on the basis of identification of the ekhonegativny zones connected with dystrophic changes of a tumor it can be suggested about existence of a hromaffinoma (see).

Russian cabbage soup tovidny gland (see) normal on echograms has a fine-grained structure. At a diffusion enlargement of the thyroid gland of local changes of its acoustic structure it is not observed. Cysts of a thyroid gland have an appearance of educations with smooth and accurate contours; adenoma of gland decides as dense education on a clear boundary, the internal structure to-rogo has the increased acoustic density in comparison with normal tissue of a thyroid gland. At cancer of a thyroid gland along with increase in its sizes the illegibility of a contour of gland and irregularity internal ekhostruk-tours is observed.

Ultrasonic diagnosis in obstetrics and gynecology. For the first time

about use of ultrasound in aku-

Fig. 4. An echogram of a small pelvis at many» fetal pregnancy for a period of 5 weeks (cross scanning): shooters

specified two fetal eggs located in a cavity of the uterus.

a sherstvo and gynecology the Scottish scientists Donald, Mac-Vikar, Brown reported in 1958 (1. Donald, J. Me Vicar, T. Brown).

In obstetric clinic At. (ekhografiya) allows to obtain information on existence and a developmental character of pregnancy (see). Identification of fetal egg at At. gives the chance to distinguish 21/2 — 3 weeks pregnancy. In early terms fetal egg is defined as the ekhonegativny formation of a round or oval form with accurate contours located usually on average or an upper part of a uterus. By 11th week of pregnancy fetal egg fills all cavity of the uterus. At duration of gestation of 4 — 4V2 weeks in most cases it is possible to receive the image of an embryo, and in 5 weeks to register its cordial activity. On 7 — the 8th week of pregnancy a physical activity of an embryo is for the first time noted. In the first trimester of pregnancy diagnosis of polycarpous pregnancy (fig. 4) is possible.

The Ekhografichesky research also gives the chance to establish not - the developing pregnancy, a full or incomplete abortion (see the Misbirth), a vesical drift (see), an extrauterine pregnancy (see). At I do not develop - shcheysya in considerable number of observations fragmentation or an illegibility of contours of fetal egg is defined, also reduction of the sizes of a fruit, lack of cordial activity and a physical activity of a fruit is noted. Sometimes in case of not developing pregnancy at an ekhografiya establish an anembrioniya (lack of a fruit in fetal egg). At a vesical drift (see) in a cavity of the uterus multiple ekhopozitivny structures, the image appear to-rykh reminds a sponge. In most cases at a vesical drift find also lyuteinovy cysts of ovaries. Existence of fetal egg outside a cavity of the uterus or a hematoma in pozadimatochny space confirm an extrauterine pregnancy.

At. allows to define duration of gestation on the basis of measurement of fetal egg and length of an embryo, and in the second and third trimesters of pregnancy — on the basis of simultaneous measurement of the biparietal size of a head, average diameter of a thorax and a stomach of a fruit.

Ekhografiya is important in diagnosis of a small-for-date fetus. Normal dependence of the biparietal size of a head of a fruit on duration of gestation can be expressed by a certain size. Reduction of the biparietal size of a head of a fruit in comparison with an estimated value at estimated duration of gestation demonstrates lag of development and a small-for-date fetus. If the difference between actual and settlement sizes is small and corresponds to lag in fetation on 2 V2 weeks, the small-for-date fetus is considered moderate; at the size corresponding to lag in development on 3 — 4 weeks, the hypotrophy is regarded as expressed. If the biparietal size is reduced considerably in comparison with the theoretical size (more than 5 weeks of lag), then the forecast of the birth of a viable fruit becomes doubtful.

Use At. allows to establish with high precision placental presentation (see), premature placental detachment (see), and also existence of cysts and calcification of a placenta (see). The placenta at ultrasonic investigation comes to light in the form of the formation of spongy structure limited on the one hand to a wall of a uterus and with another — a plate of chorion.

Important information at an ekhografiya can be obtained in cases of inborn diseases and malformations of a fruit (see). Use of an ekhografiya allows to diagnose an anencephalia, anomalies of development of extremities, hydrocephaly, a nanocephalia, spinal and craniocereberal hernias, inborn heart diseases, big defects of a diaphragm, to establish ascites, a hydrothorax, gepato-and a splenomegaly at a hemolitic disease of a fruit, an atresia of intestines, a tumor of an abdominal cavity, a hydronephrosis, a polycystosis and an agenesia of kidneys, an atresia of an urethra, a hydrocele, etc.

Important data can be obtained at At. of gynecologic diseases. Normal the uterus (see) at longitudinal scanning has an appearance of formation of a pear-shaped form with a small amount of ekhopozitivny structures in it. On cross skanogramma it has a forkhma flattened ovoi - yes. Ovaries (see) represent the formations of an ovoidny form close to a uterus and having more gentle internal structure, than a uterus. At women of childbearing age at At. they come to light almost in 96% of cases, in the period of a menopause approximately in V3 of observations.

Diagnosis of a hysteromyoma is based on increase in a uterus, roughness of its contour. In myometriums usually define single or multiple round or an oval form of education, differing in the lowered acoustic resistance. In the first phase of a menstrual cycle the cavity of the uterus does not come to light. In the second phase of a cycle on echograms in the center of a uterus the increase in acoustic density giving a median echo signal (M-echo), width to-rogo normal is registered does not exceed 6 mm. Deformation of the normal drawing of a median echo signal usually demonstrates existence of a submucous hysteromyoma, and its expansion — about a hyperplasia of an endometria or about a malignancy of a tumor. Considerable expansion of a median echo signal and abnormality of its form almost always demonstrate malignant defeat of a myometrium. Identification at ultrasonic examination of signs of small cavities (

3 — 5 mm in the diameter) in myometriums demonstrates development of internal endometriosis (see). Ultrasonic diagnosis of sarcoma of a uterus presents considerable difficulties, however bystry increase in a uterus and emergence of the centers of a necrosis in it gives the grounds to suspect this tumor.

Follicular cysts of ovaries and a cyst of a yellow body on echograms come to light as the small educations with equal y accurate contours containing liquid. The possibility of the spontaneous regression which is accurately shown at dynamic inspection is characteristic of them. Parovarian cysts have practically the same ekhografichesky signs; occasionally they can reach 100 — 200 mm and more in the diameter.

Endometrioid cysts in most cases are defined as the formations of rather small sizes (usually no more than 100 mm in the diameter) containing a finely divided suspension, and sometimes and partitions. It is necessary to carry to characteristic symptoms of these cysts their arrangement kzad and sideways from a uterus, at the same time in considerable number of observations the filled bladder does not force out them from a cavity of a small pelvis. Other characteristic symptom of an endometrioid cyst — increase in its sizes in the period of periods.

Dermoid cysts and teratomas on echograms have an appearance of formations of a round or oval form from 60 to 100 mm in the diameter including as dense, liquid components of an ekhostruktura. Due to the existence in a dense component of such environments which are strongly absorbing ultrasonic waves as teeth, the bone, nails or hair, on echograms arise acoustic shadows. Quite often dermoid cysts give a picture only liquid or only dense educations. In these cases it is almost impossible to otdifferentsirovat them from cysts and tumors of ovaries. Cystomas of ovaries of the small sizes practically do not differ from retentsionny cysts. In serous cystadenomas of the considerable sizes separate partitions and a dense pristenochny component, and in large mucinous cystomas — multiple quite often thick partitions and the finely divided not settling

suspension can come to light.

Differential ultrasonic diagnosis of dense educations in ovaries presents considerable difficulties.

In a crust, time it is not established any characteristic ekhografichesky symptoms of ovarian cancer of I and

II stages. On skanogramma in these cases reveal or only a few increased ovaries, or educations with ekhografichesky signs, usual for cystomas. In III and IV stages of ovarian cancer on echograms in cystous educations there is an image of partitions, numerous randomly located unequal on thickness, or pristenochny dense ekhostruktur, and in solid tumors — the sites of various acoustic density caused by hemorrhages and necroses. Along with it in late stages of ovarian cancer it is possible to reveal a thickening of a peritoneum, ascites, increase in steam-ortalnykh limf, nodes, sometimes a hydronephrosis.

Ultrasonic diagnosis in ophthalmology. Ultrasound examination of an eye (see) and eye-sockets (see) carry out with use of both a one-dimensional, and two-dimensional ekhografiya. Ekhooftalmograf >are supplied with ultrasonic converters with high frequency koleba-

Fig. 5. The echogram of an eye is normal: 1 — an echo signal from a front surface of a cornea; 2 — echo signals from front and back surfaces of a crystalline lens; 3 — the isoline in the field of a vitreous; 4 — the echo signals from a back wall of an eye merging with a complex of zkhosignal from retrobulbar cellulose.

niya (5 and 10 MHz) and the small diameter of the radiating plate (3 and 5 mm), to-rye have a so-called dead zone in close proximity to a piezocrystal. For this reason normal in most cases it is not possible to measure by a usual way depth of an anterior chamber of an eye and thickness of a crystalline lens since from nearby fabrics, including and from covers of an eye and its pristenochny zone, zkhosignal does not arrive or they are very weak. For elimination of a dead zone use various nozzles to the ultrasonic sensor, apply a tray blepharostat or transparent tubes with the working end opened or closed by a thin plastic membrane. The focusing converters with a nozzle and a light fixating tag in the center of a piezocrystal are intended for an ultrasonic ekhookulometriya also high-frequency (10 — 15 MHz). The last Daiopportunity to the patient independently to establish to t an eye precisely on a visual axis that is especially important at measurement of length of an axis of an eye at a high myopia.

The research of an eye is conducted after instillyatsionny anesthesia 0,25 — 0,5% solution of Dicainum, apply a drop of a liquid paraffin on a tip of the probe.

At. gives the chance to visualize internal structures of an eyeglobe (even in cases of opacity of optical environments) and an eye-socket, allows to measure depth of an anterior chamber, thickness of a crystalline lens, length of axes of an eye, degree of a vystoyaniye of a tumor of an eye or eye-socket, to reveal amotio of a retina and a choroid, to find opacifications in a vitreous, shvarta, foreign bodys, in t. h X-ray low-contrast (a stone, glass, a tree) to specify their situation concerning covers of an eye, etc. Now the ultrasonic biometrics based on definition of a time frame of passing in the studied environment of ultrasound at the known speed of its distribution in this environment is used for calculation of optical power of an artificial crystalline lens (see), diagnoses and overseeing by dynamics of miopichesky process (see Short-sightedness), differentiations of forms of primary glaucoma on open and closed-angle (see Glaucoma), diagnoses of an incomplete dislocation of a crystalline lens and identification of its swelling at a cataract, etc. The main indicator for ultrasound examination of an eye is the opacification of his refracting environments (a cornea, a crystalline lens) making impossible or complicating a usual oftalmoskopiya (see).

Normal environments of an eye are acoustically homogeneous, and echo signals arise only at reflection on limits of the section of environments (fig. 5). Heterogeneous acoustic structures of an eye-socket give a complex of the merging and gradually decreasing echo signals. At a cataract acoustic uniformity of a crystalline lens is, as a rule, broken that leads to emergence on an echogram of additional ekhopyk. The opacity of the vitreous body (see), including ge-moftaljm (see), gives additional echo signals of various amplitude depending on the size and particle density causing opacification (fig. 6). Of amotio of a retina (see) it is characteristic high steady on a big extent ekhopik, separated from the surface of an eye by the site of the isoline of various extent depending on height of amotio. The echogram at amotio of a choroid has a similar appearance (see the Choroid of an eye). However in the first case the maximum otstoyaniye from a wall of an eyeglobe is defined in back department, in the second — in a doekvatori-alny zone or in the field of the equator of an eye. In diagnosis of postoperative tsiliokhorioidalny amotio the contactless and drop method of an ekhografiya has high sensitivity. For an intraocular opu-

of Fig. 6. An echogram of an eye with opacification in a vitreous after the getting wound: echo signals of various ampla

there (are specified by an arrow).

Fig. 7. An echogram of a gpz at an intraocular tumor of i y 1MPLITUDNYY a complex of echo signals, not снижающихся^ to the level of the isoline (it is specified by an arrow).

care the located complex of the high-amplitude echo signals which are not decreasing to the level of the isoline (fig. 7) is characteristic pristenochno. At the malignant tumors which are infiltrative growing in an eye-socket the complex higher and quickly fading in comparison with the drawing of echo signals, normal for an eye-socket, usually is observed. Existence in an echogram of an eye-socket of two-three high-amplitude echo signals with sites of normal development of the isoline or the crenulate line between them is characteristic of cystous educations or the encapsulated myagkotkanny tumors, lengthening of a complex of peaks without noticeable change of their amplitude testifies, e.g., to an exophthalmos (see). Very high echo signal, however diagnosis of the located or encapsulated foreign bodys small pristenochno give foreign bodys of an eye and cavity of an eye-socket it is complicated.

Certain help in identification of fabrics on their acoustic resistance is given by a quantitative (quantitative) ekhografiya at which the size of an echo signal from the studied fabric measured in decibels is compared to the size of an echo signal from the known fabrics, napr, from covers of an eye.

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