X-ray images of cardiac lesions

Ischemic heart disease. Myocardial infarction

Ischemic heart disease is caused by impaired coronary blood flow and a gradual decrease in myocardial contractility in ischemic zones. Impaired myocardial contractility can be detected using various ultrasound diagnostic methods. The simplest and most accessible of these is echocardiography. It determines the uneven contractions of various sections of the left ventricular wall. In the ischemic zone, a decrease in the amplitude of ventricular wall movement during systole is usually observed. The thickness of the interventricular septum and systolic thickening of the myocardium are reduced. The ejection fraction of the left ventricle is reduced with increased contractions of the left ventricle (later, the ejection fraction of the right ventricle also decreases). Local contractility disorders are observed in the period when there are no pronounced signs of circulatory failure.

Valuable information about the blood flow in the heart muscle can be obtained using radionuclide studies - perfusion scintigraphy and single-photon emission tomography. Using these methods, it is possible to obtain not only qualitative but also, which is especially important, quantitative characteristics of the depth of damage to the heart muscle. Beta-dionuclide methods are especially effective when performing stress tests, in particular, a bicycle ergometric test. Scintigrams with T1-chloride are performed twice: immediately after physical exertion and after rest (for 1-2 hours). In patients with myocardial ischemia, the initial scintigram shows reduced fixation of the radiopharmaceutical. Normalization of the scintigraphic picture after rest indicates a transient circulatory disorder - stress-induced ischemia. If the previously registered defect in the accumulation of the radiopharmaceutical remains, then a persistent loss of blood circulation is observed, usually as a result of the formation of a scar on the myocardium.

Computed tomography can also be useful in diagnosing ischemic heart disease. The ischemic muscle zone under intravenous contrast has a lower density and is characterized by a delay in the contrast peak. In this zone, systolic thickening of the myocardium is reduced, and the mobility of the inner contour of the ventricular wall is reduced.

The final conclusion on the state of coronary blood flow is made based on the results of coronary angiography. X-ray images can identify coronary arteries filled with contrast agent with their 1st-3rd order branches, establish the localization and nature of pathological changes (narrowing and tortuosity of vessels, unevenness of their contours, occlusion during thrombosis, the presence of marginal defects in places of atherosclerotic plaques, the state of collaterals). However, the main purpose of coronary angiography is to determine the need and develop tactics for transluminal angioplasty or complex surgical intervention - aortocoronary bypass.

The main clinical manifestation of myocardial ischemia is known to be constant or recurrent pain in the heart area. However, similar pain may occur with myocardiopathies, aortic stenosis, dry pericarditis, lung and diaphragm diseases, esophageal motor disorders and neurocirculatory disorders. Below, in the form of a diagnostic program, is presented the tactics of radiological examination in the differential diagnosis of these pathological conditions.

One of the widely used methods of treating ischemic heart disease caused by stenosis or obstruction of a coronary artery or its branch is percutaneous transluminal angioplasty. A thin catheter with a balloon is inserted into the narrowed segment of the vessel under X-ray control. Inflation of the balloon reduces or eliminates the stenosis and restores coronary blood flow.

Acute myocardial infarction is recognized based on the clinical picture, electrocardiography results, cardiac enzyme testing, and serum myoglobin concentration. However, in doubtful cases, as well as to clarify the location and extent of the infarction and the state of pulmonary circulation, radiation methods are used. Chest X-ray can be performed in the ward or intensive care unit. Immediately after the infarction, the images show an increase in the heart shadow, venous congestion of the lungs, especially in the upper lobes, due to a decrease in the pumping function of the heart. As the patient's condition worsens, the congestion turns into interstitial edema or mixed interstitial-alveolar pulmonary edema. As the patient's condition improves, the phenomena of edema and pulmonary congestion disappear. In the first 2 weeks after the infarction, the size of the heart on repeated X-rays decreases by approximately a quarter, and in young people this happens more slowly than in older people.

Ultrasound examination can also be performed at the patient's bedside. In the first hours of the disease, it is possible to identify areas of general or local impairment of left ventricular contractility and note its expansion. Particularly characteristic is the appearance of a hypokinesia area in the area of impaired blood supply with hyperkinesia of intact adjacent areas. Repeated ultrasound examinations are important to distinguish a fresh infarction from cicatricial changes. Sonography allows us to recognize such complications of infarction as rupture of papillary muscles with impaired mitral valve function and rupture of the interventricular septum.

Direct visualization of the myocardium can be achieved by scintigraphy or single-photon emission tomography. The ischemic zone is capable of accumulating Tc-pyrophosphate and thus creating a limited area of hyperfixation (positive scintigraphy). When T1-chloride is administered to the patient, the scintigraphic picture of the heart is the opposite: against the background of a normal image of the heart muscle, a defect in the accumulation of the radiopharmaceutical is determined (negative scintigraphy).

Radiation methods are necessary for recognizing post-infarction aneurysm. Ultrasound scanning and CT reveal thinning of the ventricular wall in the aneurysm area, paradoxical pulsation of this wall section, deformation of the ventricular cavity, and decreased ejection fraction. Dopplerography reveals vortex blood movements in the aneurysm and decreased blood flow velocity in the apex of the ventricle. Intracardiac thrombi can be detected both on sonograms and on CT scans. MRI can be used to determine the area of myocardial infarction and obtain a direct image of the cardiac aneurysm.

Mitral valve defects

Radiation diagnostics of mitral heart defects is based mainly on ultrasound and X-ray data. In case of mitral valve insufficiency, its flaps do not close completely during systole, which leads to blood being thrown from the left ventricle into the left atrium. The latter is overfilled with blood, and the pressure in it increases. This affects the pulmonary veins, which flow into the left atrium - venous plethora of the lungs develops. The increase in pressure in the pulmonary circulation is transmitted to the right ventricle. Its overload leads to myocardial hypertrophy. The left ventricle also expands, since with each diastole it receives an increased volume of blood.

The radiographic picture of mitral valve insufficiency consists of changes in the heart itself and the pulmonary pattern. The heart acquires a mitral shape. This means that its waist is smoothed out, and the right cardiovascular angle is located above the usual level. The second and third arcs of the left contour of the cardiac shadow protrude into the pulmonary field due to the expansion of the pulmonary cone and the trunk of the pulmonary artery. The fourth arc of this contour is lengthened and approaches the midclavicular line. With severe valve insufficiency, expansion of the pulmonary veins is determined as a manifestation of venous plethora of the lungs. On the images in oblique projections, an enlargement of the right ventricle and left atrium is outlined. The latter pushes the esophagus back along an arc of large radius.

The value of ultrasound examination is determined by the fact that the morphological picture is supplemented by data on intracardiac hemodynamics. Dilation of the left atrium and left ventricle is revealed. The amplitude of the mitral valve opening is increased, vortex movements of blood are recorded above its flaps. The wall of the left ventricle is thickened, its contractions are intensified, and in systole a reverse (regurgitant) blood flow into the left atrium is determined.

When the mitral orifice is narrowed, the blood flow from the left atrium to the left ventricle is impeded. The atrium expands. The blood remaining in it during each systole prevents the pulmonary veins from emptying. Venous pulmonary congestion occurs. With a moderate increase in pressure in the pulmonary circulation, only an increase in the caliber of the pulmonary veins and an expansion of the trunk and main branches of the pulmonary artery occur. However, if the pressure reaches 40-60 mm Hg, then a spasm of the pulmonary arterioles and small branches of the pulmonary artery occurs. This leads to an overload of the right ventricle. It must overcome two barriers: the first - at the level of mitral valve stenosis and the second - at the level of spasmodic arterioles.

In the case of mitral orifice stenosis, the X-ray examination also shows a mitral configuration of the heart, but it differs from mitral valve insufficiency. Firstly, the waist of the heart is not only smoothed, but even bulges due to the pulmonary cone, the trunk of the pulmonary artery and the left atrial appendage. Secondly, the fourth arc of the left contour of the heart is not elongated, since the left ventricle is not enlarged, but, on the contrary, contains less blood than normal. The roots of the lungs are expanded due to the branches of the pulmonary artery. The consequence of lymphostasis and edema of the interlobular septa are narrow thin stripes in the lower outer parts of the pulmonary fields - the so-called Kerley lines.

The most indicative is the ultrasound picture of mitral orifice stenosis. The left atrium is dilated. The mitral valve cusps are thickened, their image on sonograms may be layered. The velocity of diastolic closure of the mitral valve cusps is reduced, and the posterior cusp begins to move in the same direction as the anterior (normally, the opposite). In Dopplerography, the control volume is located primarily above the mitral valve. The Dopplerogram curve is flattened, in severe cases the blood flow has a turbulent character.

Both X-ray and sonography may reveal calcifications in the mitral ring. On sonograms, they cause strong echo signals; on radiographs, they appear as irregularly shaped lumpy shadows, often grouped into a ring of uneven width. CT, especially when performed on an electron beam tomograph, has the greatest sensitivity in detecting calcification. It allows even microcalcification to be recorded. In addition, CT and sonography make it possible to determine the formation of a thrombus in the left atrium.

Each of the mitral defects is rare in isolation. Usually, a combined lesion is observed with the formation of mitral valve insufficiency and, at the same time, stenosis of the orifice. Such combined defects have the features of each of them. A peculiar pathological condition of the mitral valve is its prolapse, i.e., sagging of one or both of its cusps into the cavity of the left atrium at the moment of contraction of the left ventricle. This condition is recognized by ultrasound examination in real time.

Aortic defects

In case of aortic valve insufficiency, its cusps do not ensure the tightness of the left ventricle: in diastole, some of the blood from the aorta returns to its cavity. Diastolic overload of the left ventricle occurs. In the early stages of the defect formation, compensation is achieved by increasing the stroke volume. Increased blood ejection leads to expansion of the aorta, mainly in its ascending part. Hypertrophy of the left ventricular myocardium develops.

X-ray examination reveals the aortic shape of the heart. The waist of the heart is noticeably deepened and emphasized as a result of the lengthening and convexity of the left ventricular arch. Sonography immediately reveals deep and rapid contractions of the left ventricle and equally sweeping pulsation of the ascending aorta. The cavity of the left ventricle is dilated, the diameter of the supravalvular section of the aorta is increased. Additional data are also important: hypertrophy of the left ventricular myocardium and small-amplitude oscillations of the anterior mitral valve leaflet from the return wave of blood.

In another aortic defect - aortic stenosis - the left ventricle does not empty completely during the systole phase. The remaining blood, together with the blood flowing from the left atrium, creates additional volume, as a result of which the cavity of the left ventricle expands, so on radiographs the heart takes on an aortic shape. The arch of the left ventricle is rounded and shifted to the left. In parallel, the ascending part of the aorta expands, since a strong stream of blood rushes into it through the narrowed opening. In general, the picture is similar to aortic insufficiency, but there is a distinctive feature: if you perform fluoroscopy, then instead of fast and deep contractions of the heart, slow and tense movements of the wall of the left ventricle are observed. Naturally, this sign - the difference in the nature of the movement of the gastric wall in two types of aortic defect - should be detected by ultrasound examination, and fluoroscopy is permissible only in the absence of echocardiography data.

Sonograms clearly show an increase in the size of the left ventricle chamber and thickening of the myocardium, clearly visible are the compacted cusps of the aortic valve and their reduced divergence during systole. At the same time, a pronounced turbulent nature of the blood flow is noted at the level of the aortic valve and in the supravalvular space. In aortic defects, especially in stenosis, lime deposits are possible in the area of the fibrous ring and valve cusps. They are detected both in X-ray examination - on X-rays, tomograms, computer tomograms, and on sonograms.

The combination of stenosis and insufficiency of the aortic valve, both in X-ray and ultrasound examination, is manifested by a combination of signs of each of the defects. It should be noted that not only aortic defects lead to the aortic configuration of the heart on X-ray images, but also diseases such as hypertension and atherosclerosis of the aorta.

Among the interventional procedures for heart defects, mainly mitral stenosis, is valvuloplasty. For this purpose, a balloon catheter is used: when the balloon is inflated, the adhesions between the valves are torn.

Congenital defects

Manuals on internal medicine and surgery describe numerous anomalies in the development of the heart and large vessels (congenital defects). Radiation methods play an important, and sometimes decisive, role in their recognition. Even a routine X-ray examination establishes the position, size and shape of the heart, aorta, pulmonary artery, superior vena cava and the nature of their pulsation. For example, with abnormal venous drainage of the lungs, a large vein appears against the background of the lower sections of the right lung, which does not go to the left atrium, but in the form of a curved trunk goes to the diaphragm (the "scimitar" symptom) and then to the inferior vena cava. Such anomalies as the inverse arrangement of internal organs, dextrocardia, underdevelopment of the left branch of the pulmonary artery, etc. are clearly recorded. Of particular importance is the assessment of the blood filling of the lungs. In such defects as patent ductus arteriosus (Botallo's duct), aortopulmonary window, atrial or ventricular septal defect, Eisenmenger's complex, blood flow into the pulmonary circulation (left-to-right shunt) is observed, since the blood pressure in the left ventricle and aorta is higher than in the pulmonary artery system. Consequently, when analyzing the radiograph, arterial plethora of the lungs is immediately noticeable, and vice versa, in those defects in which blood flow into the pulmonary circulation is impaired (tetrad and triad of Fallot, pulmonary artery stenosis, Ebstein's anomaly), a decrease in pulmonary vascularization is observed. Dopplerography with color mapping and magnetic resonance angiography make it possible to directly record blood movement and volumetric blood flow velocity in the chambers of the heart and large vessels.

In conclusion, we will add that radiation studies are very important both for monitoring the course of the postoperative period and for assessing the long-term results of treatment.

Pericarditis

Dry pericarditis initially does not produce symptoms when examined by radiological diagnostic methods. However, as the pericardial layers thicken and harden, its image appears on sonograms and CT scans. Significant pericardial adhesions lead to deformation of the heart shadow on radiographs. Calcium deposits in pericardial adhesions are especially clearly visible. Sometimes the heart on radiographs seems to be enclosed in a calcareous shell ("armored heart").

Accumulation of fluid in the pericardium is reliably recognized using ultrasound diagnostic methods. The main sign is the presence of an echo-free zone between the posterior wall of the left ventricle and the pericardium, and with a larger volume of fluid - in the area of the anterior wall of the right ventricle and behind the left atrium. The amplitude of pericardial movements, naturally, is significantly reduced.

Cardiac effusion is diagnosed with the same confidence using CT and MRI. CT data can also be used to some extent to judge the nature of the effusion, since the admixture of blood increases the absorption of X-ray radiation.

Accumulation of fluid in the pericardial cavity leads to an increase in the heart shadow on the radiograph. The organ shadow takes on a triangular shape, and the image of the cardiac arches is lost. If drainage of the pericardial cavity is necessary, it is performed under ultrasound control.