X-ray of the lungs - soft tissue summation chest. In the path of X-rays, some structures absorb and others reflect radiation. Such a game is displayed on x-ray film or digital media.

The radiologist reads X-ray, consisting of a complex of shadows of white and gray colors. Their combination with each other forms an image that a specialist deciphers and makes a description.

Our specialists are ready to decipher readers' radiographs free of charge. We also suggest that you carefully deal with the complex of x-ray shading and clearing on your own.

X-rays of the lungs are normal

X-ray images of the lungs (thoracic organs) are analyzed according to the "PoChiFora and InRiCoS" scheme. How to decipher these terms:

• By - position;
• Chi is a number;
• Fo - form;
• Ra - dimensions;
• Ying - intensity;
• Ri - drawing;
• Co-contours;
• C - displacement.

This algorithm is taught to students medical universities preparing to become radiologists.

Consider, for example, an x-ray of the lungs in a normal state:

It visualizes a lot of blackouts and brightenings (white and black) that can intimidate readers. In fact, this radiograph is simply deciphered (see the following picture)

All anatomical structures are labeled on the x-ray to make it easy for readers to understand. We suggest remembering the intensity of the lung fields. The norm does not imply the presence of pathological darkening (white) and enlightenment (dark color), which are not present in the image.

If you "fill your eyes", learn to clearly distinguish the norm from the pathology.

X-ray of healthy lungs, how to read

X-ray of healthy lungs should be described according to the classical standard. First, records are made of pathological x-ray syndromes, then lung fields, roots, domes of the diaphragm, costophrenic sinuses, cardiac shadow and soft tissues.

How to make an x-ray of the lungs of a child correctly and without consequences

The classic algorithm for describing healthy lungs:

• In lung fields without visible focal and infiltrative shadows;
• The roots are not expanded, structural;
• Contours of the diaphragm and costophrenic sinuses without features;
• Heart shadow of the usual configuration;
• Soft tissues without features.

The above radiograph falls under this description.

Chest X-ray for pneumonia - pathology

X-ray of the lungs with pneumonia is a classic manifestation of pathology. We give an example of a picture with inflammatory changes lung tissue(pneumonia), so that readers understand the difference between the norm and pathology.

We suggest that you familiarize yourself with the pictures below with pneumonia and in the norm. Answer the question, where the radiograph is normal and which is pathological. Determine which x-ray shows pneumonia.

Let's say that the darkening is small and localized above the aperture.

X-ray of healthy lungs is a classic of radiology, since radiology is focused on the detection of tuberculosis, cancer and pneumonia.

Reading the radiograph

On the presented radiograph of the lungs, an infiltrative shadow is visualized in the supraphrenic zone on the left. Roots are heavy. Costophrenic sinuses are not veiled. Heart shadow of classical configuration. Pathology in soft tissues is not traced.

Conclusion: X-ray signs of left-sided segmental pneumonia. Recommended x-ray of the chest in the left lateral projection to establish the localization of blackout.

Digital X-ray - what is it and how to read it

The digital radiograph is a product of modern developments in radiology. In the era of the birth of X-ray diagnostics, in order to obtain an image after the passage of X-rays through the anatomical structures of the body, it was necessary to use fixatives, developers to create a photo negative. The process is similar to developing film by photographers.

Modern technology has made it possible to get rid of this time-consuming procedure. Film has been replaced by digital research. They involve the use of special sensors that register the intensity of the rays at the exit from the object of study and transmit information to software. It analyzes the signals and displays a digital image on the screen. It is analyzed by a radiologist. When reading a picture, a specialist gets the opportunity to enlarge or reduce the image, convert a negative into a positive, and many other functions.

ATLAS OF RADIOLOGY OF INJURED DOGS AND CATS

Joe P. Morgan and Pim Woolvekamp

Atlas of the radiology of injured dogs and cats

Joe P. Morgan, MD, MD

School of Veterinary Medicine

University of California

USA

Pim Woolvekamp MD, PhD

Faculty of Veterinary Medicine

Utrecht University, The Netherlands

Foreword

General provisions

1. The importance of obtaining high-quality radiographs.

   Characteristics of a diagnostic study

   radiographic evaluation.

X-ray diagnostics of the thoracic organs in trauma

1. Introduction

   The radiographic appearance of the chest is normal.

   Radiographic changes due to chest trauma.

3.1 Destruction of the chest wall (respiratory-motor system)

3.2 Presence of fluid or air in the pleural cavity.

3.3 Diaphragm tear

3.4 Damage to the lung parenchyma

3.5 Damage to the mediastinum.

4. radiographic illustrations.

111. X-ray diagnostics of the abdominal organs in trauma

1. Introduction.

2. Radiographic changes due to abdominal trauma.

2.1 Injury of peripheral soft tissues.

2.2 Fractures.

2.3 Peritoneal fluid.

2.4 Retroperitoneal fluid .

2.5 Air in the peritoneal cavity.

2.6 Food/faeces in the peritoneal cavity.

2.7 Enlargement of organs.

2.8 Combined picture.

3. X-ray contrast studies for injuries of the abdominal cavity.

1. Injuries of the urinary tract.

2. Injuries of the gastrointestinal tract.

1V. X-ray diagnostics of musculoskeletal injuries

Introduction.

Axial skeleton injuries

1. Localization of fractures

   Osteomyelitis.

Additional skeleton injuries.

1. Classification of fractures.

   Fracture localization.

   Other skeletal diseases caused by trauma.

   Devices for orthopedic fixation.

Joint damage

1. Anatomical localization.

   Other joint diseases caused by trauma.

pathological fractures.

Soft tissue injuries.

Radiographic illustrations.

Subject index.

Foreword

In diagnostic radiology, it is essential good technique obtaining images and the correct interpretation of radiographic changes. This Atlas contains a lot of useful technical advice on how to properly perform x-ray examinations of injured animals. Radiographic signs in the diagnostic study are clearly defined. Most of the illustrations are low-contrast overviews taken with a top-mounted tube and vertical x-rays. In addition, the use of simple contrast methods for radiodiagnosis of abdominal injuries and the advantages of obtaining images with a horizontal X-ray path with a vertical cassette are discussed.

However, the main emphasis in the Atlas is on the interpretation of x-rays. For convenience, the text is divided into three main sections: chest injuries, abdominal injuries, and musculoskeletal injuries. In each section, the discussion is based on the characteristic radiographic changes in that area. For example, an increase in the volume of free peritoneal fluid in the abdominal cavity is discussed not only in relation to the resulting radiographic pattern, but also discussed possible reasons increase in its volume. This is supported in the text by a table that conveniently lists radiographic features that can be used to diagnose increased volume of peritoneal fluid.

This Atlas is primarily addressed to practitioners veterinarians as an aid in their ongoing battle to diagnose and treat injured dogs and cats. The scope of this text is limited to these views. In most of these cases, animals should be treated as patients requiring emergency care: some have life-threatening injuries, others have traumatic injuries that require simple diagnosis and treatment. Many of the selected cases involve animals involved in a car accident, but other types of traumatic injuries have also been described.

Particularly because animals cannot speak, and because of the difficulty of performing a thorough and adequate physical examination in many injured animals, the use of diagnostic x-rays, often whole-body x-rays, is of great help in the immediate diagnosis of injuries. This reliance on diagnostic radiology has made veterinary radiology an established specialty. However, in the middle of the night, there may not be a specialist nearby, and in all likelihood, on-call veterinarians should perform the first X-ray diagnosis themselves. At this point, Atlas will help them. It can also be useful for students, as it describes the basics of X-ray diagnostics used in the practice of treating small animals. Viewing illustrated cases with captions provides another way to learn and understand this diagnostic specialty, as nothing can replace the picture-reading experience gained from case studies. It is intended that the Atlas will be used as an advisor and thus should be kept close to the negatoscope within reach in case guidance is needed to analyze the resulting radiograph.

Emphasis is placed on illustrating cases, which are examples of certain radiographic principles and patterns. This must be kept in mind when using the Atlas, as it is not possible to include examples of all radiographic pathologies seen in injured animals. The “Aunt Minnie” approach is a completely different method of diagnostic interpretation of radiographs. This method assumes that by examining enough x-rays and remembering their appearance, that person will be adequately prepared when the next injured animal arrives at the clinic. However, this system does not function satisfactorily, since it is clear that the radiographs of the next patient will be different from all the radiographs that have already been encountered.

Therefore, it is necessary to rely on the identification and understanding of radiographic features that contain radiographic changes (“X-ray features”) resulting from various pathophysiological abnormalities. Therefore, it is strongly advised to try to recognize these signs and then, most importantly, to discover how they develop and what they mean. Only then can one freely read radiographs in which there is so much important information hidden that can still be revealed if only a specialist notices it.

In many cases, images are obtained in two orthogonal x-ray projections. When the second projection does not change the radiographic interpretation, it is omitted. When the second projection was not available, an explanation is given for this. All images of the chest and abdomen in the lateral projection are obtained from the animal laid with the head pointing to left side. Dorsoventral (thoracic) and ventrodorsal (abdominal) images are taken in ventrodorsal projection, with the animal's head pointing up the page. This means that the right side of the animal is on the left side of the page. The cases presented were originally examined at the Veterinary Teaching Hospital, School of Veterinary Medicine, University of California, Davis and the Department of Radiology, Department of Veterinary Medicine, Utrecht University. This Atlas is a combination of the professional experiences of two longtime colleagues who have enjoyed the time they have spent together both professionally and socially. The authors express their sincere gratitude to the many professional colleagues, faculty members and residents who have made direct and indirect contributions to obtaining the information presented in the Atlas. Finally, special thanks go to the special qualifications and experience of many radiologists and photographers, without whom the creation of this Atlas would not have been possible. Do not forget that without a diagnostic x-ray it is impossible to make an accurate diagnosis. Our thanks go to this group of often unrecognized professionals.

General provisions

Trauma can be defined as a sudden applied physiological force that results in anatomical and physiological disturbances. The severity of the changes varies depending on the amount of force applied, the means by which it is applied, and the anatomical location of its application. A traumatic event may only slightly affect a small part of the animal's body and cause only mild discomfort, or it may result in severe injury to numerous areas of the body and impair the function of vital organ systems. Before understanding the impact of an injury on any part of the body, it is necessary to realize that it is the amount and severity of associated injuries that usually determines the final outcome. The true lethality of any individual injury can only be accurately assessed when these factors are taken into account.

Trauma is a great danger to the health of the animal. A significant percentage of animals seen by a small animal clinician come after a traumatic event. Many animals are severely injured, and their mortality rate is higher due to spontaneous death or due to euthanasia requested by the owners or recommended by doctors, due to the severity of the injury. For this reason, it is important to understand the use of radiology as a diagnostic and prognostic aid and to learn how to use it to greater advantage.

The most common causes of injury include traffic accidents in which an animal is struck by a bicycle, motorcycle, car or truck, or a wheel passes over the body, or the animal is dragged some distance by a vehicle. Animals that have been involved in a fight with other animals constitute another large group of animals with injuries usually caused by biting. In the event of a collision between a large and a small dog, the smaller animal can be strongly “shaken” and receive multiple puncture wounds in addition. Animals falling from a height include those that live in large cities and whose damage is the result of a fall from the window of an apartment located high enough above an adjacent road or sidewalk. Other similar injuries are the result of animals jumping into or falling into a deep ditch while walking in hilly terrain. Crush injuries occur in small animals when household items are accidentally dropped on them, causing serious injury. Penetrating injuries often occur and depend on the nature of the environment. Damage may result from various gunshot wounds or point wounds with sharp objects or impalement on a sharp object. Unfortunately, human abuse is becoming more and more of an injury to animals and includes almost unimaginable types of injury. Without a history suggestive of trauma, the clinician should remember to add the trauma to the list of possible causes until the animal's problem is better understood.

It is important that the veterinarian at the time of admission be able to begin prompt treatment to avoid a fatal outcome in the hours or days following the injury. Due to the vital nature of many of the body's organs, these devastating injuries can quickly lead to death, often before treatment. This is obvious when you consider that many of these animals die before being admitted to the clinic. Animals that survive to receive emergency veterinary care may have survived the most critical time period associated with injury and have a good chance of survival if diagnosed and treated accurately.

Radiology is an important diagnostic tool in the evaluation of injured animals. The amount of time and money spent on this procedure can be significant, and x-rays are often prioritized arbitrarily. It is not uncommon for injured animals to be examined radiographically for fractures and dislocations, while chest or abdominal radiography is not performed. Injured animals rarely die from a broken femur. However, death due to bleeding into the peritoneal cavity or due to unsuspected diaphragmatic hernia is not uncommon. This lack of attention to chest and abdominal x-rays in injured animals is astonishing, as it has been clearly shown that very often in animals with serious injuries, such as pneumothorax, diaphragmatic rupture, bleeding into the abdominal cavity or bladder rupture, only minimal clinical signs and a single lesion are not considered prior to X-ray examination. That is, an injured animal must be examined for the presence of life-threatening injuries.

Therefore, it is important to emphasize from the outset the main benefit of X-ray diagnosis of injured animals. Radiography assists the clinician in the following areas:

recognize the cause and extent of a life-threatening condition in more detail than is possible with physical examination alone (Figure 1-1).

differentiate the most serious condition for immediate treatment when multiple lesions are present (Figure 1-2).

reconsider the effectiveness of emergency treatment if the improvement in the animal's condition is less than expected (Fig. 1-3).

provide a permanent record that can be used as the basis for ongoing evaluation of the animal's recovery progress (Figure 1-4).

In this regard, it is important to emphasize that the exclusion of pathologies is important as a positive confirmation of their existence!

The timing of the X-ray examination in the initial period of treatment of an injured animal is very important. Radiography usually makes it necessary to make a compromise between the need for information that must be obtained from an x-ray examination and the stress caused to the animal by doing so. Life-threatening respiratory and circulatory emergencies or abdominal injuries should be controlled and the animal's vital signs stabilized before radiographic examination is considered. At the most early stages treatment of changing the position of the body of the animal and manipulation with it may be contraindicated.

X-ray examination should be postponed if:

the condition of the animal may be aggravated during x-rays.

the expected benefit of radiography does not outweigh the risk.

possible changes in the course of treatment are unlikely.

In most injured animals, a single lateral examination can be performed without great risk to them, and important information can be gained from this examination, even though it is incomplete. Don't forget that it's important to finally get a full X-ray, with an additional orthogonal X-ray, as soon as possible. This is especially important in emergencies caused by chest trauma, in which a picture only in the lateral projection can be misleading and hide important information. If orthographic imaging cannot be routinely taken due to stowage limitations, the use of horizontal projection x-rays may be considered (Figure 1-5). This is of additional help, especially when examining free air or fluid due to pneumothorax, pleural effusion, or pneumoperitoneum. Animals with suspected spinal injury should undergo radiographic examination as early as possible to determine the assistance that should be given to stabilize the vertebral fracture. In animals with this type of lesion, an orthogonal X-ray should be taken using horizontal rays in order to exclude ventrodorsal laying, in which they lie on their backs.

Manipulating an injured animal with limb fractures may not be life-threatening. However, the nature of the fracture can be changed by increasing the degree of fragmentation or additional soft tissue injury.

It may be necessary to administer appropriate sedatives or pain medication if the level of pain interferes with obtaining good quality radiographs. In this situation, it is important to be ready to provide emergency care during the examination and the animal should be intubated either before the examination or everything should be prepared for it.

Importance of obtaining high-quality radiographs

Poor quality of radiographs due to technical error(s) greatly increases the possibility of misjudgment of the image. This is a particular problem in injured animals, as there may be difficulty in laying down the animal or in carrying out a complete x-ray examination. There is a natural tendency to exclude repeat x-rays of injured animals and to deny that non-diagnostic x-rays were obtained. It is not uncommon, when assessing poor quality images, to overestimate the significance of shadows due to dirt on the animal's coat, and mistake artifacts or normal anatomical variations in oblique projection for lesions, leading to a false positive assessment. However, most often technical errors interfere with visualization of the lesion, leading to a false negative interpretation.

The position of the animal is very important. Radiographic examination of the chest and abdomen in injured animals requires the use of both lateral and ventrodorsal (VD) or dorsoventral (DV) projections. However, the choice of lateral view and the choice of either VD or DW views often depends on the nature of the injury and how the animal can be comfortably positioned.

Comparison of chest images in the VD and DV projections shows a significant difference in the form of the diaphragm (Fig. 1-6). With a LW projection, X-rays pass through the diaphragm at almost a right angle to its surface; thus, the distance between the shadow of the ventral part of the diaphragm and the two dorsally located crura of the diaphragm is usually equal to the length of 3-4 vertebral bodies. In VD projection, X-rays pass through the diaphragm almost parallel to its surface; thus, the distance between the shadows of the ventral part of the diaphragm and the dorsally located diaphragmatic crura is small and usually less than the length of one vertebral body. The silhouette of the heart also differs in DV and VD projections. The heart "drops" laterally when the deep-chested animal is laid down in a dorsal recumbent position, creating an elongated silhouette of the heart. In the LW projection, the heart "leans" into a more normal position and has an oblique silhouette "in the form of a teardrop." The choice of VD or DV abdominal view is less important and is usually determined by the comfort of the injured animal. With DV projection, the gas bubble is visible at the bottom of the stomach. In the VD projection, the gas bubble is displaced and outlines the pylorus and descending duodenum (Fig. 1-7).

Regardless of projection, almost all examinations of the chest of small animals are performed on animals in the supine position. This means that the lower lobes of the lungs are compressed and contain little air. As a result, little contrast remains between lung injury and surrounding healthy lungs to allow identification of either infiltrative or focal lung neoplasms. The compression of the examined lung is caused by the pressure of the abdominal contents on the diaphragm, the masses of the heart, and the pressure of the table surface on the lower part of the chest prevents its expansion. Thus, comparing right and left lateral views, or VD and DV views, always allows the lungs to be visualized in a manner that provides a more complete assessment than using only one view. The nature of the suspected lesion may influence the choice of projection under which the assessment is best made. The choice of right or left lateral view for abdominal examination is of lesser importance (Fig. 1-8).

Rotation of the animal during lateral examination of the chest leads to the layering of a light shadow of the spinal column on a part of the dorsal field. Oblique DV/VD projection makes the silhouette of the heart appear larger and shifts the spinal column laterally, leading to partial closure of one lung field, while the field of the other lung appears greatly enlarged. An oblique direction due to poor positioning of the animal is less important for examination of the abdominal cavity, since the organs in it are located more freely and do not have a fixed localization or radiographic appearance.

Characteristics of a diagnostic study

The standard setup for a full chest and abdomen x-ray includes one lateral and either VD or DV view. For limbs, two orthographic projections are used. Most clinicians are more familiar with the appearance of the right lateral chest radiograph and choose this lateral view. In traumatized animals, it is usually less stressful to receive chest x-rays in a direct projection in the lying position on the sternum (LB). Unfortunately, this does not allow full chest coverage to give the same good lung image as can be obtained from the VD view. On abdominal radiographs, most clinicians are familiar with the appearance of right lateral radiographs. In injured animals, any lateral view is acceptable, given that the left lateral view is more useful for assessing the pylorus and duodenum (Figures 1-8).

Instead of obtaining a second orthogonal image, only one single lateral view in the supine position is erroneously used to evaluate injured animals. This is the most serious technical error. This guide contains examples of lateral projections that were found to be insufficient to carry out complete diagnosis. As an example, it may be necessary to obtain both right and left lateral chest images in the supine position to identify a lesion that was initially identified only in the VD or DV view.

Incorrect cassette size often interferes with thoracic examination when the cassette used is not large enough to allow full thoracic examination, including the entrance to the thorax and the entire diaphragm. To make a good lateral view of the chest, the central beam must be centered on the heart and shoulders, and the forelimbs must be moved forward so that their shadow does not overlap the front of the lung field. With the head and neck slightly extended, the anterior chest, including the trachea, is more clearly visible. When examining the abdominal cavity, both the diaphragm and the pelvis must be included, and the examination will be incomplete if these two anatomical regions are not assessed, as traumatized animals often show damage to them. When examining the extremities, attempts should be made to capture both ends of the injured bone to ensure a complete examination of the lesion. The study of the entire limb in the lateral projection on a large picture is in a good way survey study, but it should be carried out before surgery on an anesthetized animal.

The use of the correct exposure is absolutely essential for a good examination of an injured animal. Incorrect settings can be a common technical problem due to inaccurate measurements of the animal. The following technical scheme can be recommended: 1) use the highest possible peak voltage in pvc to allow the use of a reduced microcoulomb (mAc), 2) use the highest current in milliamps, and 3) use the shortest exposure time possible. This ensures that an X-ray machine with sufficient capacity is used correctly and radiographs are taken. High Quality. A high MAC setting reduces radiographic contrast, resulting in a relatively gray image with low contrast differences between different tissue densities. This method is used in chest x-rays. A low peak kV setting results in high contrast radiographs. This method is more suitable for abdominal radiography. Errors in the choice of method may be due to the limitations of the machine itself, in such cases it must be understood that the x-ray machine or imaging system (cassettes, screens and film) does not have sufficient capacity, especially for chest x-rays. In posttraumatic dyspnea, chest contents move rapidly, so exposure time should be 1/30 second or less to avoid blurring (artifact of movement) in chest examination. More long time Exposure results in lung movement and deterioration of radiographic detail in the image. Using a combination of a higher speed class rare earth intensifying screen and an appropriate film reduces the required radiological exposure and is an alternative to purchasing a more powerful machine. X-rays of the abdomen or musculoskeletal structures are easier because these structures are not as mobile. To study them, you can choose a slower film-screen combination or a fast system, which is used for chest x-rays. For these studies, a low peak kV installation, about 70 kV, is used.

Appropriate use of a screening grating contributes significantly to improving image quality. It should be used in animals that have a thorax greater than 15 cm or an abdominal cavity greater than 11 cm. It is extremely important to use the grid in injured animals, due to the possibility of pleural, pulmonary or peritoneal hemorrhage, which increases tissue density and leads to radiation scattering. The grating absorbs most of the scattered radiation, which causes fogging of the image and loss of contrast in the x-ray image.

Either stationary gratings can be used, in which grating lines are observed on the radiograph, or moving gratings, which perform oscillatory movements during exposure, which leads to darkening of their lines, and they become invisible on the resulting radiograph. Stationary grating with narrow interconnections reduces image sharpness. This type of grating is more suitable for use with the short exposure times required for chest x-rays of injured animals, as the older type of moving grating does not move fast enough to obscure the grating lines, causing the grating lines to remain visible on the radiograph.

The best film-screen combination for chest x-rays of injured animals, when the x-ray machine has limited power, is to use one of the durable rare earth screens with a suitable high latitude film. This makes it possible to use shorter exposure times, up to 1/6 of those used before, and obtain radiographs with low contrast without motion artifacts.

These high-speed systems produce radiographs that may appear somewhat grainy, with some loss of detail or sharpness compared to fine-grained screens. However, the loss of detail due to the use of high-speed systems is less than the loss of detail due to the effect caused by lack of motion sharpness. Although important problem in chest x-rays, the choice of film-screen combination is less important in x-rays of the abdomen and extremities, due to the reduced ability of animals to move during exposure.

If the X-ray machine is of a high class, a screen of a small speed class can be selected, along with obtaining an adequate radiographic exposure with short time exposure. The use of low-speed systems improves the quality of radiographs, as the resulting images are much less grainy.

Intensifying screens must be free from surface artifacts due to dirt or loss of treatment solution. Many of these screen artifacts can be removed by simply cleaning the screen surface. However, if they remain for any length of time, they become permanent, leading to the artifacts that are seen on every radiograph taken with this cassette.

3 Radiographic evaluation.

There are two main methods for image analysis. The first method is to “remember” the type of disease or pathological changes that are expected to be present, and then, when analyzing the radiograph, carefully look for these signs. This approach is adopted in traditional medical textbooks, which present the disease with a description and illustration of a typical x-ray image. The difficulties with this approach are the same as the difficulties of finding knowledge about a really sick animal in the textbook used. Clinical information about the injured animal is often uncertain and questionable. The same applies to information available from radiographs. In many animals, the radiological picture of the disease is “not typical”, and therefore the textbook approach leads to confusion and misdiagnosis.

The second method of image evaluation is the ‘radiographic symptoms’ method. This is a much more accurate method of image analysis. It involves analyzing the pictures taken, isolating the x-ray symptoms, and then comparing them to the various conditions known to cause them. Since the radiograph often has many symptoms that characterize the involvement of more than one organ, a systematic analysis using deductive reasoning leads to an appropriate differential diagnosis.

Successful analysis of radiographs must be systematic in order to ensure that the entire radiograph is fully examined. This means that it is necessary to think over a system for analyzing images, which is based either on the anatomical principle of the study, or on the physical principle of radiographs.

The use of the anatomical method requires that every organ visible on the radiograph be recognized and evaluated.

The physical method begins with the examination of peripheral structures and continues in successive steps, reducing the field of view until the central region of the image is reached.

A big mistake in analyzing an x-ray of an injured animal is to immediately search for the expected lesion found on the physical examination, thereby overlooking other important information contained on the x-ray.

In this book, for the purpose of examination, the body of an animal is divided into three regions: the thorax, the abdomen, and the musculoskeletal system. Although this provides convenient way presentation, it is important not to forget that traumatic injuries often result in damage to more than one area of ​​the body. Often multiple x-ray studies are required.

Rice. 1-1Paracostal hernia in combination with diaphragmatic hernia

Physical examination of this injured 5-year-old domestic shorthair cat revealed a paracostal hernia with prolapsed loops. thin department intestines into the subcutaneous rupture. However, the severity of possible intrathoracic pathologies could only be guessed at. Chest x-ray revealed an additional diaphragmatic hernia, with a gas-filled stomach (straight arrows) in the left side of the thoracic cavity and mediastinal and cardiac displacement (rounded arrows) to the right, which is seen on a dorsoventral view.

Rice. 1-2 Diaphragmatic hernia in combination with expansion and volvulus of the stomach.

A 3-year-old domestic shorthair cat presented with clinical signs of dyspnea and severe abdominal distension after being hit by a car. Chest x-ray revealed small intestinal loops on the left side of the chest, suggesting a diaphragmatic hernia (A). Complementary abdominal radiographs showed a greatly dilated and gas-filled stomach in a rolled-up position (B). Due to the displacement of the loops of the small intestine through the left-sided rupture of the diaphragm, the entrance to the stomach (arrow) and the duodenum have shifted to the left side with the closure of their lumen. Swallowing air led to a life-threatening expansion of the stomach.

Rice. 1-3Chylothorax, recurrence after reconstructive surgery

This 10-year-old domestic shorthair cat developed severe shortness of breath following a road traffic accident. A chylothorax due to a ruptured thoracic duct was diagnosed, and a successful thoracic operation was performed to close the duct. However, after 3 days, the cat again became short of breath. Chest x-ray revealed a massive pleural effusion with compression-atelectasis of the apical and cardiac lobes of the lung.

Rice. 1-4 "Dangling" chest with protrusion of the lobe of the lung.

A 3-year-old Samoyed was hit by a motorcycle and brought to the clinic with severe shortness of breath, in a state of shock, with severe labored breathing and a “dangling” segment of the left chest wall. A clinical examination revealed diffuse subcutaneous emphysema and the presence of a fracture of the ribs in combination with a mass of soft tissues on the left chest wall. Due to the animal's distress, only one lateral x-ray was obtained (A). The first x-ray did not provide sufficient additional information regarding the severity or nature of the chest injury. After fluid therapy, additional dorsoventral images were obtained (B, C). These images provided more accurate information about the condition of the chest. Four adjacent ribs on the left side of the chest (ribs 4-7) were crushed and displaced. The heart was noticeably displaced to the left side and was in contact with broken ribs. Tracheal displacement to the left was also observed (rounded arrows). Outside the thorax, well-demarcated soft tissue masses were visible, which were outlined by subcutaneous gas (straight arrows). During the operation, it was revealed that they turned out to be the left apical lobe of the lung, which fell out through a violation of the chest wall.

Rice. 1-5 False cysts of the lungs (pneumatocele)

Twelve days after a 5-year-old Hovawart was hit by a car, the dog was brought in for a chest x-ray. The lateral recumbent image (A) revealed several localized, well-circumscribed fluid-density structures (arrows) that appeared to be contained in the lobes of the lungs. Horizontal tracing of a dog in a standing position (B) showed horizontal levels of fluid in these structures. These changes are radiographic signs of traumatic false cysts of the lungs filled with blood and air. After 6 weeks these false cysts completely disappeared, and the radiographic appearance of the chest cavity returned to normal (C).

Rice. 1-6 Diaphragm Diagram

These diagrams show strong differences in the radiographic appearance of the diaphragm in the dorsoventral projection (A), when the x-rays pass through it at right angles, and the ventrodorsal projection (B), when the x-rays pass the diaphragm parallel to it.

Rice. 1-7 Scheme of the stomach.

These diagrams show the differences in the appearance of the stomach. On the dorsoventral view (A), the gas bubble is located at the fundus of the stomach, while on the ventrodorsal view (B), it is located in the pylorus and duodenum.

Rice. 1-8 Schemes of the stomach.

These diagrams show the differences in the appearance of the stomach. On the right side view (A), the gas bubble is located at the bottom of the stomach, while on the left side view (B), it is located in the pylorus and duodenum.

X-ray diagnostics of the thoracic organs in trauma

1. Introduction

Radiology is the most important diagnostic tool in the study of chest injuries. It provides more accurate information than a physical examination and can be relatively cheap, fast and safe, providing a quick result on which to base a diagnosis and/or treatment decision. An x-ray image is the translucence of the body at the time the image is taken. It is the ability to see the image of the internal organs of the animal, which is impossible with palpation or auscultation, that is the reason for the great value of chest x-ray. Good contrast, provided by air in the lungs, opens a window to the organs of the chest cavity on survey radiographs, to a degree that is not possible with an x-ray examination of the abdominal cavity.

Accurate x-ray diagnosis is vital, as the physical signs of thoracic dysfunction after injury are often unclear. In addition, x-rays provide temporal measurements, making it possible to observe the dynamics of changes as they are discovered in the course of the disease. Radiography reproduces the features of the animal's chest on film, which can be examined both during the initial examination and later.

Since the lungs contain mostly air, they normally have a relatively dark (radiolucent) appearance on film under normal exposure. The increased lung density is due to either an increase in air content or an increase in liquid content. As a result, the lungs are whiter than normal (increased lung opacity). It is a common finding in injured dogs or cats due to pulmonary hemorrhage. It is also possible that the lungs become more radiolucent (low density/opacity of the lungs). It occurs in hypovolemic states. A problem in determining lung opacity arises in animals with a diffuse or generalized pattern that provides little opportunity for comparison between abnormal and normal lung shadows.

Although injuries to the chest are common and often life-threatening, it is still not as easy to injure the chest and its contents as it might seem. The ribcage is firm and resilient owing to its strong spring-like ribs. The lungs provide additional protection for the heart due to their air cushion effect. Because of this protection, almost all damage to the chest is caused by the high-energy force generated by a severe injury. Therefore, chest injuries are often part of a constellation of injuries that affect several areas of the animal's body. Although radiographic examination often provides specific information at the time of injury, it is also important in tracking the healing process by providing information about changes that appear secondarily at later points in time. Late development of bleeding in the mediastinum is an example of such damage. Radiodiagnosis can also be used as a pre-anaesthesia study in older animals or when heart disease is suspected. More specific reasons for a chest x-ray include evaluation of known or suspected non-cardiogenic edema following several types of uncommon trauma, such as:

electric shock,

Almost complete drowning

head injury, or

Almost complete asphyxia.

Normal chest x-ray

The most important diagnostic decision is whether radiographs characterize normal or abnormal chest, and this decision is often the most difficult to make (Fig. 2-1). The chest of dogs varies greatly due to age and breed differences. The breed and age of the patient affect conformation and are important causes of variability. Chest radiographs in puppies, adults, and older animals vary greatly with age. Degenerative changes without clinical significance, such as pulmonary fibrosis or costal cartilage ossification, may closely resemble the clinically important lesions seen in injured animals (Figure 2-1).

Respiratory phase greatly affects the radiographic appearance of the chest and can be difficult to control in the trauma patient. An image taken during an exhalation is very different from one taken during a full inhalation. This must be taken into account, as these differences are large enough to lead to misdiagnosis of lung diseases. On exhalation, the lungs are relatively more radioopaque and smaller, with a reduced angle between the diaphragm and spine in lateral view and between the diaphragm and chest wall in DV or VD view. The triangle formed by the posterior border of the heart, the lower part of the diaphragm and the caudal vena cava is smaller during exhalation. Also in the exhalation picture, the dome of the diaphragm is more convex and juts forward and has more contrast with the heart, which appears relatively larger due to the reduction in chest size; while the ribs are closer together and at a greater angle to the spine (Fig. 2-2).

Obesity is common, especially in older animals, and creates a general increase in opacity due to more soft tissue. Increased opacity of the lungs is also due to insufficient filling of the lungs, since breathing in obese animals is usually shallow. As a result, it is very often impossible to obtain good chest images due to inadequate lung filling. The resulting underexposure can lead to false diagnosis lung diseases, since the artifactual increase in lung density strongly resembles a diffuse pulmonary infiltrate, which may be associated with pulmonary hemorrhage.

Radiographic changes due to chest trauma.

Having decided that the chest x-ray indicates the presence of pathologies, the next question is to determine the nature of the damage and the clinical significance of the pathological change. This can be done very quickly by assessing the chest in a categorical way.

Structural damage to the chest caused by trauma can be easily divided into five categories:

destruction of the chest wall (respiratory-motordevice)

presence of fluid or air in the pleural cavity

diaphragmatic rupture (“ diaphragmatic hernia” )

damage to the lung parenchyma

damage to the mediastinum (heart, large vessels, thoracic duct and esophagus).

For x-ray examination of the lungs, fluoroscopy and radiography are used. With the help of these two main research methods, X-ray morphological structural changes in the lungs are established and their functional state is revealed.

Concerning special methods X-ray examination - fluorography, tomography, X-ray kymography, etc., which are widely used in medicine, in veterinary radiology So far, only fluorography has been used. The method of using fluorography for mass examination of the lungs in sheep was developed by R. G. Mustakimov.

X-ray of the lungs in all animal species is performed with the lateral course of the rays from right to left or from left to right on a standing animal, since this position corresponds to the anatomical, topographic and physiological norm of the organs located in the chest cavity. The lung tissue is in natural aerocontrast and gives a differentiated shadow image without the use of contrast agents.

Start research with general inspection chest with a wide open diaphragm. At the same time, the size and shape of the lung field, the density of the costal shadows, the respiratory amplitude of the diaphragm, the degree of transparency of the lungs during inhalation and exhalation, the nature of the heart pulsation and the state of the vascular-bronchial pattern are considered and studied. The aperture is then narrowed to limit the outgoing cone of rays and thereby increase the contrast and sharpness of the image. After that, they proceed to a consistent thorough examination of all parts of the lungs.

R. M. Vaskanyan recommends using the contact method to obtain greater image clarity, that is, bringing the x-ray tube close to the chest. For better visibility of the apical lobes in small animals, young calves and dogs thoracic limbs lead forward.

Upon detection pathological changes in the lungs, their location, number, size and shape, density and clarity of boundaries are determined.

In large animals, due to the impossibility of simultaneous and separate imaging of the right and left lungs, the localization of changes is judged by the clarity of their images. Therefore, animals are examined from both sides. If the shadow of the pathological focus at different positions of the animal noticeably changes the degree of clarity of the outline of the boundaries, then, consequently, the pathological focus is localized either in one or the other lung. If the shadow does not noticeably change the degree of clarity with changes in the position of the animal, then the pathological focus is in the mediastinum (A. I. Vishnyakov).

In small animals and dogs, multi-axis fluoroscopy is used to determine the localization of pathological changes in the lungs (see "Transillumination Technique").

For the convenience of recording and locating pathological changes in the lungs, Taskin proposed to divide the entire lung field into three pulmonary triangular fields. The first upper, or vertebro-diaphragmatic, triangle, formed by the diaphragmatic lobes of the lungs, is limited by the spinal column, diaphragm, posterior vena cava and tangent to the border of the heart. The second, lower, or cardio-diaphragmatic triangle includes the cardiac lobes of the lungs; limited by the diaphragm, the posterior border of the heart and the shadow of the posterior vena cava. The third, sternocardiac, triangle is formed by the apical lobes of the lungs; lies between the anterior border of the heart and the sternum. It is seen in small animals, calves and dogs.

However, a more accurate location of pathological changes in the lungs is determined by the ribs in the same way as in the clinic.

During translucence or at the end of it, to clarify small details or obtain an objective document - radiographs - radiography is performed. In large animals, the picture is taken in a lateral projection. When clarifying the state of the right lung, a right picture is taken; if it is necessary to examine the left lung, a left x-ray is taken.

In some cases, for diagnosis, A. I. Vishnyakov recommends using an oblique projection when the rays travel from above obliquely down or from below obliquely upwards. V. A. Lipin recommends taking a picture of one lung in the dorso-ventral projection. When directing the central beam of rays along the outer edge of the thoracic vertebrae, retreating 3-4 fingers from the sagittal line.

In small animals and dogs, a direct x-ray is taken to obtain a separate image of the lungs, fixing the animal on its back or stomach.

It must be remembered that when taking a picture from working organs, the quality of the image to a large extent depends on the ratio between the shutter speed and the speed of movement of the organ; this ratio determines the value of the so-called kinematic unsharpness. Therefore, to reduce the latter and obtain a radiograph rich in fine details, it is necessary to reduce the shutter speed.

Komarova K.A., Naletova K.N.
Veterinary clinic "Center", Moscow

Source: materials of the XVI Moscow international congress small animal diseases

As you know, one of the main methods of examination of the chest organs is radiography. This research method makes it possible to assess not only the structural organization of organs, but also, in the presence of pathognomonic signs, to judge their functional state. In this regard, knowledge of anatomy is a prerequisite for decoding radiographs and subsequent diagnosis. It should be taken into account that X-ray anatomy, in contrast to topographic, has its own specifics, due to the lack of visualization of certain structures and organs in the norm.

To minimize the risk of diagnostic errors and adequate visualization of the chest, it is necessary to perform radiographs in at least two mutually perpendicular projections (for example, right lateral and direct ventrodorsal projections), while taking into account the phase of the respiratory cycle. So, the most informative is the radiograph made in the phase of deep inspiration. A radiograph taken in the phase of maximum expiration is not subject to interpretation due to the loss of airiness of the lung tissue.

The thorax can be divided into 4 main areas: the structures that bound the chest cavity, the pleural space, the lung parenchyma, and the mediastinum (including the heart and great vessels). Each structure and organ has a characteristic size, brightness, density, edge and contour, quantity and localization.

Structures bounding the chest cavity

The structures that bound the chest cavity include the skeleton of the chest, the soft tissues of the chest wall, and the diaphragm. Borders of the chest cavity: ventrally - segments of the sternum, dorsally - vertebral bodies and ribs, laterally - ribs, intercostal soft tissues, subcutaneous structures, forelimb, caudally - diaphragm. The cranial part of the chest is limited by the soft tissues of the ventral part of the neck and the entrance to the chest.

When examining these structures and organs, it is necessary to accurately determine the localization of the pathology, if necessary, perform additional radiographs (radiographs at an angle of 45°, collateral radiographs).

Pleural cavity

The lungs are covered with pleura. It is a smooth shiny serous membrane. Distinguish the parietal pleura. and visceral (pulmonary), between which a gap is formed - the pleural cavity, filled with a small amount of pleural fluid. The pulmonary pleura directly covers the parenchyma of the lung and, being tightly fused with it, goes into the depth of the interlobar furrows. The parietal pleura is fused with the walls of the chest cavity and forms the costal pleura, and the diaphragmatic pleura, as well as the mediastinal pleura that limits the mediastinum from the sides.

Normally, the pleural cavity contains a small amount of fluid, which is not visualized on the radiograph, and the pleura is also not visualized in the normal state. In older patients, pleural thickening is sometimes seen, which is usually seen between the right middle and right caudal lung lobes, and is better visualized in the left lateral view, however, if there are no other abnormalities, this fact should not be taken into account.

lung parenchyma

It consists of 3 components that are normally visualized on plain radiographs:

1. walls airways at the level of the main and secondary bronchi.
2. pulmonary arteries and veins
3. lung interstitial tissue - lung framework

Airway walls are visualized as thin rectilinear soft tissue lines that narrow and branch to the periphery. The bronchi that run parallel to the x-rays look like a circle. In adult dogs, the tracheal and bronchial walls and cartilaginous rings may undergo dystrophic mineralization and will be more contrasting. In the right lateral projection, the first oval in superposition with the trachea at the base of the cardiac silhouette shows the bronchus of the right cranial pulmonary lobe. The bronchus of the left cranial lung lobe is approximately 1 cm long in medium to large dogs and is divided into the bronchi of the cranial and caudal segments of the left cranial lung lobe. Further caudally, at the bifurcation, the trachea divides into the main bronchi. The right main bronchus continues into the right middle bronchus, which is better visualized in the left lateral projection. The bronchus of the accessory pulmonary lobe is located caudal to the cardiac silhouette and the right main bronchus.

Pulmonary arteries and veins. On a lateral radiograph, the pulmonary arteries lie dorsal to their respective airways, which in turn lie dorsal to their respective veins (ABC principle). On ventrodorsal or dorsoventral radiographs, the pulmonary arteries appear lateral to the bronchus and the vein medially. This relationship is very important. An adequately exposed radiograph should clearly show branching pulmonary vessels along the periphery of the lung fields. These pulmonary vessels have the largest diameter at the heart, gradually decreasing and branching towards the periphery. Branching is linear and should not be twisted and irregular (not symmetrical) or truncated sharply into a cone.

Vessels have an average x-ray density. Generally, the size of any pulmonary artery, including the pulmonary parenchyma, should match the size of the corresponding pulmonary vein at any level. The relative size of the pulmonary artery and vein can be determined by comparison with each other, and more precisely by the skeletal method. For example, pulmonary artery and the vein supplying the right cranial lobe of the lung should not be larger than the diameter of the proximal edge of the 4th rib. Also, the diameter of the artery and vein of the caudal lobe of the lung should be equal to the thickness of the diameter of the 9th rib at the point of intersection, or the total shadow of the decussation of the vessel and the 9th rib should be a square. If the vessel is enlarged, this shadow is stretched into a horizontal rectangle, and if it is reduced, into a vertical rectangle. It is important to realize that such a comparative method as the size of a vessel with a rib is only approximate and does not give a 100% correct diagnosis.

lung interstitial tissue this is the part of the lungs that does not contain air, in which the pulmonary vessels, bronchi, lymphatic structures and the lung parenchyma (alveolar walls, interlobular septum) are located. On a plain chest x-ray, the interstitial tissue forms a lace-like shadow of medium radiographic density. various kinds animals, the content of connective tissue in the lungs is different. As a result, the lungs of animals with great content connective tissue on the x-ray will normally be more “white” (dense). By placing the species in ascending order of the amount of connective tissue in the lungs, the following line is formed - a dog and a cat, then a horse, cattle, and a person.

Mediastinum

This is the space between the right and left lung sacs. In dogs and cats, the mediastinal pleura is underdeveloped, which implies that nonvisceral pleural effusions and transudates will be bilateral. Exudative effusions (such as pyothorax, chylothorax, hemothorax) tend to be unilateral, in which case occlusion of the opening of the inferior mediastinal pleura must be present.

On their way, the cranial edges of the parietal pleura of both lungs diverge in the upper and lower sections and form a triangle of the thymus gland (cranioventral) behind the handle of the sternum, and in lower section- pericardial triangle (caudoventral). These triangles are important landmarks. Thymus and sternal lymph node - 2 soft tissue structures located in the cranioventral triangle. The sternal lymph node is not visualized normally. The thymus is visualized as a seal, which usually has the form of a curved triangular shadow at the medial edge of the left cranial lobe of the lung in the left side of the chest. This phenomenon is called “sailing syndrome”. In puppies and kittens, the thymus is sometimes visualized in a lateral view between the right cranial pulmonary lobe and the cardiac silhouette. More often, the thymus can be visualized on ventrodorsal and dorsoventral projections in the cranioventral triangle between the left and right cranial lung lobes. The caudoventral triangle forms a left lateral extension of the accessory lobe of the lung in the ventrodorsal and dorsoventral projections.

The fold of the pleura in the area of ​​the caudal vena cava is not visible as a clear structure. The tissues surrounding the trachea on lateral radiographs merge with soft tissue structures, including vessels, esophagus, lymph nodes and nerves, which cannot be distinguished because their shadows overlap. The right margin of the cranial mediastinum on ventrodorsal and dorsoventral radiographs usually forms the lateral margin of the cranial vena cava.. .

Trachea on ventrodorsal and dorsoventral projections, normally slightly shifted to the right from middle line. Dorsally in the middle of the mediastinum, the trachea ends with a bifurcation to the main bronchi

Descending aortic arch visualized between the right and left caudal lung lobes. On ventrodorsal and dorsoventral projections, the aortic arch is located slightly to the left of the midline. The descending aorta continues in a curved line towards the vertebral bodies to the central aortic opening of the diaphragm.

Esophagus usually not visualized on plain chest radiographs. The dorsal part of the middle part of the mediastinum also contains the tracheobronchial lymph node, the phrenic nerve, the vagosympathetic trunk, and other structures that are not normally visible.

Lungs

They are a paired organ that occupies approximately 50% of the chest. The right lung is divided into the right cranial, right middle, right caudal, and accessory lobes. The left lung is divided into the left cranial (which is divided into cranial and caudal parts) and the left caudal lobe. Normally, interlobar fissures are not visualized.

The notch between the right cranial and right middle lobes is located at the level of the 4th-5th intercostal space,
- the notch between the right middle lobe and the right caudal lobe is located at the level of 6-7 intercostal spaces,
- the notch between the cranial and caudal parts of the left cranial lobe is located at the level of the 4th intercostal space,
- notch between the left cranial and left caudal lobes is located at the level of 6-7 intercostal space.

Dorsal to the heart, the right cranial lobe is in contact with the right caudal lobe, and the cranial part of the left cranial lobe is adjacent to the left caudal lobe. Interlobar notches can only be seen if there is a thickening of the pleura or an increase in pleural fluid.

The very first task of the radiologist is to decide on the presence or absence of pathological changes on the radiograph. In view of the wide variety of species, breeds of animals, as well as age specificity and the impossibility of conducting research in a strictly defined respiratory phase, this task presents no small difficulties and requires great experience and completeness of knowledge from the doctor.

Summary
Komarova K.A., Naletova K.N. Normal radiological anatomy of a thorax. Center veterinary clinic.

In this article it is told about normal radiological anatomy of a thorax. The knowledge of anatomy is an obligatory condition of decoding of the roentgenogram and the subsequent statement of the diagnosis. Thus it is necessary to consider that radiological anatomy, unlike topographical, has the specificity caused by the absence of visualization of certain structures and bodies in norm.

On November 8, 1895, professor of physics at the University of Würzburg V.K. Roentgen, while conducting experiments to study the passage of a high voltage current through a Crookes-Gittorf tube, discovered unknown rays that caused a screen coated with barium platinum-cyanogen to glow. For seven weeks, Roentgen worked intensively on the study of the properties of these rays, and only on December 28, 1895, did the first report appear on a new type of rays, they were called x-rays. Later, at the suggestion of the anatomist Kelliker, the rays were called x-rays.

X-ray radiation refers to electromagnetic, arises as a result of deceleration of fast moving electrons at the moment of their collision with the anode of the X-ray tube. The use of X-rays for clinical diagnostics diseases is based on its ability to penetrate through various organs and tissues, cause the glow of certain chemical compounds, and also have a photochemical effect on x-ray film.

An X-ray image is formed in the system: X-ray emitter (tube) - object of study - image receiver (X-ray film, screen, semiconductor plate). It is based on the uneven absorption of X-ray radiation by various anatomical structures, organs and tissues of the subject.

As is known, the intensity of X-ray absorption depends on the atomic composition, density and thickness of the object under study. The heavier the tissues entering chemical elements and the greater the density and thickness of the layer, the more intense the absorption of x-rays. Conversely, tissues composed of elements with a low atomic number usually have a low density and absorb X-rays to a lesser extent. In other words, X-ray radiation is absorbed to the greatest extent by bones, to a much lesser extent by soft tissues, and least of all by tissues containing air.

Uneven absorption of X-rays in the tissues of the area under study causes the formation in the space behind the object of an altered or inhomogeneous beam of X-rays (output dose). In fact, this beam contains images invisible to the eye. By acting on a radiographic film or screen, it creates a familiar x-ray image.

Radiography is one of the most common and very informative methods of X-ray examination. This technique allows you to get an image of almost any anatomical region. At the heart of obtaining an x-ray image are the processes occurring in the photosensitive layer of the x-ray film.

The radiographic image is negative (reverse). On a radiographic film, the blackest (darkest) areas of the image correspond to structures that have a low density and thickness, i.e. transparent to x-rays. This is, first of all, airy lung tissue, gas-containing intestines and paranasal sinuses nose, soft tissues (especially fatty). On the contrary, bones, various calcifications, massive formations and other anatomical structures that intensively absorb radiation are created on the film of enlightenment. So, for example, when x-raying the chest, against the background of dark (black) airy lung tissue, light shadows of the ribs, heart, large vessels, pathological formations lung tissue.

When performing radiography, it is necessary to strive for standardization of the research condition, which is achieved:
1. Standardization of styling for each anatomical region.
2. Standardization of technical shooting parameters.
3. Standardization of the process of photochemical processing of the film.

Usually, the study begins with radiography in typical, or, as they say, in standard projections. As a rule, this is a survey - in direct and lateral projections with the sagittal and frontal direction of the X-ray beam, in a standing position to determine the level and amount of fluid in the abdominal and chest cavities.
Sometimes pictures are taken under conditions of execution functional tests, during flexion and extension of the studied joint.

Before shooting, the area under study is placed in the center of the cassette, and the axis (body, limbs) is parallel to the film. The X-ray beam is directed to the center of the cassette perpendicular to its plane, since the shadow of a linear object will have largest size, when its longitudinal axis is perpendicular to the path of the rays, and if the longitudinal axis coincides with the path of the rays, then only a point can be seen in the image instead of a linear object.

High quality radiographs can only be obtained with full
immobility of the study area during the survey.

A rather difficult issue is the development of physical and technical conditions for radiography different areas animal bodies. It is necessary to observe the focal length accepted for a certain area of ​​the body, its value is determined by the requirements for obtaining the sharpest images, and also take into account the thickness of the body part being studied.
An important point in radiography is the choice of the optimal voltage at the poles of the tube (stiffness). Measured in kV. As the voltage increases, short-wavelength and more deeply penetrating or hard X-rays are obtained. As the voltage decreases, long wavelength and less penetrating or soft x-rays are obtained.

The hardness of X-ray radiation has to be changed, taking into account the unequal thickness of different parts of the animal body. The thinner the object, the softer the rays are needed and the thicker, the harder.

When shooting objects with a thickness of up to 2 cm, you need to use a voltage of no more than 60 kV, a thickness of 2-6 cm - up to 70 kV, a thickness of 6-10 cm or more with a voltage of 70-100 kV.

The correctness of the choice of X-ray hardness can be assessed by the characteristic details of the finished radiograph.

Soft shots have a velvety black background. The bone structure is clearly visible only in thin sections of the skeleton. The image of the bone sections, which have a large thickness, is not worked out, devoid of details.
With a properly selected hardness, the radiograph has a dark gray tone. The bone structure is clearly visible throughout the studied part of the skeleton. Soft tissues are clearly visible a large number of image details.

Pictures taken with excessive voltage on the tube are characterized by a gray background. There is a lot of shadow detail, but the contrast is low, so the image of small details often blends into the background.
Important in radiography right choice exposure, quantity electric current passed through the tube during the shooting. It is found by the product of mA. per shutter speed in seconds, express the exposure in mA.

The correctness of the choice of exposure can be checked by visual control over the development process.

In case of insufficient exposure, the image of anatomical structures, especially dense or having a significant thickness ( lumbar spine, neck, skull) occurs slowly. Only thin parts of the animal's body, or those with a low density, are well worked out.
With normal exposure, the image appears quickly after 40-60 s and ends after 6-8 minutes.

Overexposure is characterized by a rapid onset and a very rapid completion of the development process. By the end of development, there is a significant fog on the image, which reduces the quality of the image. It should be remembered that slight fluctuations in exposure up to 30% practically do not affect the quality of the x-ray image.