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Normal x-ray anatomy of the heart

Medical expert of the article

Oncologist, radiologist
, medical expert
Last reviewed: 06.07.2025

Radiological examination of the morphology of the heart and great vessels can be performed using non-invasive and invasive techniques. Non-invasive methods include: radiography and fluoroscopy; ultrasound examinations; computed tomography; magnetic resonance imaging; scintigraphy and emission tomography (single- and dual-photon). Invasive procedures include: artificial contrasting of the heart by venous means - angiocardiography; artificial contrasting of the left cavities of the heart by arterial means - ventriculography, coronary arteries - coronary angiography and aorta - aortography.

X-ray techniques - radiography, fluoroscopy, computed tomography - allow to determine with the greatest degree of reliability the position, shape and size of the heart and main vessels. These organs are located among the lungs, so their shadow clearly stands out against the background of transparent pulmonary fields.

An experienced doctor never begins a heart examination by analyzing its image. He will first glance at the owner of this heart, since he knows how much the position, shape and size of the heart depend on the person's build. Then, using the images or X-ray data, he will evaluate the size and shape of the chest, the condition of the lungs, and the level of the diaphragm dome. These factors also affect the nature of the heart image. It is very important that the radiologist has the opportunity to examine the pulmonary fields. Such changes in them as arterial or venous congestion, interstitial edema characterize the state of the pulmonary circulation and help diagnose a number of heart diseases.

The heart is an organ of complex shape. Radiographs, fluoroscopy and computer tomograms produce only a flat two-dimensional image of it. In order to get an idea of the heart as a three-dimensional formation, fluoroscopy requires constant patient rotations behind the screen, and CT requires 8-10 or more slices. Their combination makes it possible to reconstruct a three-dimensional image of the object. Here it is appropriate to note two newly emerging circumstances that have changed the traditional approach to radiological examination of the heart.

Firstly, with the development of the ultrasound method, which has excellent capabilities for analyzing heart function, the need for fluoroscopy as a method for studying heart activity has practically disappeared. Secondly, ultra-high-speed computer X-ray and magnetic resonance tomographs have been created, which allow three-dimensional reconstruction of the heart. Similar, but less "advanced" capabilities are possessed by some new models of ultrasound scanners and emission tomography devices. As a result, the doctor has a real, and not imaginary, as with fluoroscopy, opportunity to judge the heart as a three-dimensional object of study.

For many decades, cardiac radiography was performed in 4 fixed projections: direct, lateral and two oblique - left and right. Due to the development of ultrasound diagnostics, now the main projection of cardiac radiography is one - direct anterior, in which the patient lies against the cassette with his chest. In order to avoid projection enlargement of the heart, its imaging is performed at a large distance between the tube and the cassette (teleradiography). At the same time, to increase the sharpness of the image, the radiography time is reduced to a minimum - to several milliseconds. However, in order to get an idea of the radiological anatomy of the heart and great vessels, a multi-projection analysis of the image of these organs is necessary, especially since the clinician has to deal with chest images very often.

On the radiograph in the direct projection the heart gives a uniform intense shadow, located in the middle, but somewhat asymmetrically: approximately 1/3 of the heart is projected to the right of the midline of the body, and Vi - to the left of this line. The contour of the shadow of the heart sometimes protrudes 2-3 cm to the right of the right contour of the spine, the contour of the apex of the heart on the left does not reach the midclavicular line. In general, the shadow of the heart resembles an obliquely located oval. In individuals with a hypersthenic constitution, it occupies a more horizontal position, and in asthenics - a more vertical one. Cranially, the image of the heart passes into the shadow of the mediastinum, which at this level is represented mainly by large vessels - the aorta, superior vena cava and pulmonary artery. Between the contours of the vascular bundle and the cardiac oval, the so-called cardiovascular angles are formed - notches that create the waist of the heart. Below, the image of the heart merges with the shadow of the abdominal organs. The angles between the contours of the heart and diaphragm are called cardiophrenic.

Despite the fact that the heart shadow on radiographs is absolutely uniform, its individual chambers can still be differentiated with a certain degree of probability, especially if the doctor has radiographs taken in several projections, i.e. from different shooting angles. The fact is that the contours of the cardiac shadow, normally smooth and clear, have the shape of arcs. Each arc is a reflection of the surface of one or another section of the heart emerging on the contour.

All arcs of the heart and blood vessels are distinguished by their harmonious roundness. Straightness of the arc or any of its sections indicates pathological changes in the heart wall or adjacent tissues.

The shape and position of the human heart are variable. They are determined by the patient's constitutional features, his position during the examination, and the breathing phase. There was a period when people were very keen on measuring the heart on X-rays. Nowadays, they usually limit themselves to determining the cardiopulmonary coefficient - the ratio of the heart diameter to the chest diameter, which normally fluctuates between 0.4 and 0.5 in adults (more in hypersthenics, less in asthenics). The main method for determining heart parameters is ultrasound. It is used to accurately measure not only the size of the heart chambers and vessels, but also the thickness of their walls. The chambers of the heart can also be measured, and in different phases of the cardiac cycle, using computed tomography synchronized with electrocardiography, digital ventriculography or scintigraphy.

In healthy people, the heart shadow on the radiograph is uniform. In pathology, lime deposits can be found in the valves and fibrous rings of the valve openings, the walls of the coronary vessels and aorta, and the pericardium. In recent years, many patients have appeared with implanted valves and pacemakers. It should be noted that all these dense inclusions, both natural and artificial, are clearly detected by sonography and computed tomography.

Computer tomography is performed with the patient in a horizontal position. The main scanning section is selected so that its plane passes through the center of the mitral valve and the apex of the heart. Both atria, both ventricles, the interatrial and interventricular septa are outlined on the tomogram of this layer. The coronary groove, the attachment site of the papillary muscle, and the descending aorta are differentiated on this section. Subsequent sections are allocated both in the cranial and caudal directions. The tomograph is switched on synchronized with the ECG recording. In order to obtain a clear image of the heart cavities, tomograms are performed after a quick automatic introduction of a contrast agent. Two images taken in the final phases of heart contraction - systolic and diastolic - are selected from the resulting tomograms. By comparing them on the display screen, it is possible to calculate the regional contractile function of the myocardium.

New perspectives in the study of heart morphology have been opened by MRI, especially when performed on the latest models of ultra-high-speed devices. In this case, it is possible to observe heart contractions in real time, take pictures in specified phases of the cardiac cycle and, naturally, obtain parameters of heart function.

Ultrasound scanning in different planes and with different sensor positions allows to obtain an image of the heart structures on the display: ventricles and atria, valves, papillary muscles, chords; in addition, it is possible to identify additional pathological intracardiac formations. As already noted, an important advantage of sonography is the ability to evaluate all parameters of cardiac structures with its help.

Doppler echocardiography allows recording the direction and speed of blood movement in the cavities of the heart, identifying areas of turbulent eddies at the site of emerging obstacles to normal blood flow.

Invasive methods of studying the heart and blood vessels are associated with artificial contrasting of their cavities. These methods are used both to study the morphology of the heart and to study central hemodynamics. During angiocardiography, 20-40 ml of radiopaque substance is injected using an automatic syringe through a vascular catheter into one of the vena cava or into the right atrium. Already during the introduction of the contrast substance, video filming on a film or magnetic carrier begins. During the entire study, which lasts 5-7 seconds, the contrast substance consistently fills the right chambers of the heart, the pulmonary artery system and pulmonary veins, the left chambers of the heart and the aorta. However, due to the dilution of the contrast substance in the lungs, the image of the left chambers of the heart and aorta is unclear, so angiocardiography is used mainly to study the right chambers of the heart and the pulmonary circulation. With its help, it is possible to identify a pathological connection (shunt) between the chambers of the heart, a vascular anomaly, an acquired or congenital obstruction to the blood flow.

For a detailed analysis of the condition of the ventricles of the heart, a contrast agent is injected directly into them. The examination of the left ventricle of the heart (left ventriculography) is performed in the right oblique anterior projection at an angle of 30". The contrast agent in the amount of 40 ml is injected automatically at a rate of 20 ml/s. During the introduction of the contrast agent, a series of film frames is started. Filming is continued some time after the end of the introduction of the contrast agent, until it is completely washed out of the ventricle cavity. Two frames are selected from the series, made in the end-systolic and end-diastolic phases of heart contraction. By comparing these frames, not only the morphology of the ventricle is determined, but also the contractility of the heart muscle. This method can reveal both diffuse dysfunctions of the heart muscle, for example, in cardiosclerosis or myocardiopathy, and local zones of asynergy, which are observed in myocardial infarction.

To examine the coronary arteries, a contrast agent is injected directly into the left and right coronary arteries (selective coronary angiography). The images taken in various projections are used to study the position of the arteries and their main branches, the shape, contours and lumen of each arterial branch, and the presence of anastomoses between the left and right coronary artery systems. It should be noted that in the vast majority of cases, coronary angiography is performed not so much to diagnose myocardial infarction, but as the first, diagnostic stage of an interventional procedure - coronary angioplasty.

Recently, digital subtraction angiography (DSA) has been increasingly used to examine the cavities of the heart and blood vessels under artificial contrast. As noted in the previous chapter, DSA based on computer technology allows for an isolated image of the vascular bed without shadows of bones and surrounding soft tissues. Given the appropriate financial capabilities, DSA will eventually completely replace conventional analog angiography.

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