Diagnostic imaging techniques of Cardiovascular

2021-07-02 12:19 PM

When the ribcage is stretched, the heart is not resting on the diaphragm but in a suspended state. At that time, the longitudinal axis is almost parallel to the vertical axis of the body

Cardiovascular X-ray technique

Skill

For conventional imaging techniques, position the heart as close to the film as possible.

Cardiac imaging focal distance - film > 1.5m (télécoeur).

In order to see the posterior cardiac arcs, the patient must be given barium to drink into the esophagus.

Take the film while the patient inhales.

Capture the chambers of the heart with 4 classic poses

Cardiac angiography and selective vasculature must do cardiac catheterization.

Ultrasound examination techniques, Computed tomography, Magnetic resonance of the heart and blood vessels.

Four Classical Postures and Radiological Anatomy

Straight posture:

The chambers of the heart overlap to form borders (right, left). On each bank there are arcs.

Right bank:

Superior arch: superior vena cava, ascending aortic arch in the elderly.

Lower arch: Right atrium.

Left bank:

Superior arch: Aortic arch.

Middle arch: Pulmonary artery.

Inferior arch: Left ventricle.                              

Tilt Pose:

Mainly to see the front and backshore:

Front edge:

Superior arch: Aortic arch.

Inferior arch: Right ventricle.

Backshore:

Left atrium upper 1/3.

Left ventricle lower 2/3.

The pulmonary master windows.

Right anterior oblique position:

It is the position of the 4 chambers of the heart.

Left front lateral position:

Is the position to view the aortic arch, the pulmonary aorta.

Figure: The edges and the arc of the heart are straight.

Figure: Left lateral lateralization of the contours and arcs of the heart.

Figure: Right anterior oblique position of the cardiac contours and arches.

The diameters of the heart

Longitudinal diameter L:

The diameter from D - G' is the diameter of the shaft that penetrates from the bottom to the top of the heart (L » 13 - 14 cm).

L represents the relationship of the heart to the thorax and abdomen.

L makes an angle with the vertical line.

In the normal person a # 45 0 .

In tall skinny people a < 45 0 .

In low fat women a > 45 0 .

Figure: Diameters of the heart.

Bottom Diameter B:

As the D'G line, the base of the heart is mainly 2 atria (B » 9.5 - 10.5 cm).

Horizontal Diameter H:

The sum of the mG and mD segments from 12 to 13.5 cm is the diameter of the right atrium and the left ventricle. It is used to calculate the thoracic index.

ICP hay QCP (heart - lung quotient) = H / Th.

Th: the maximum diameter of the thorax, normally this indicator is 50%.

Diameter of the aorta (aortic nodule):

40 - 50 mm ~ 20 years old.

60 - 70 mm ~ 60 years old.       

All the above diameters also depend on the patient's body: height, age, gender, respiratory amplitude, standing or lying position, systolic or diastolic blood pressure. These diameters are abnormal only when they are out of proportion to the patient's anatomy.

Cardiovascular tomography imaging techniques

Echocardiography

As one of the main imaging techniques for the circulatory system today, with all types (Mode) 2D, TM, especially pulsed Doppler ultrasound, continuous Doppler, color Doppler, the image has been evaluated. The state and function of the heart is quite complete.

Some of the dimensions of the heart chambers, valves on ultrasound:

Dimensions of the left ventricle on ultrasound:

LVPW = 6-12mm; left ventricular chamber: LVED = 39-56 mm.

Interventricular septum IVS = 6-12mm.

Dimensions of the right ventricle on ultrasound:

RVED = < 30mm

Left ventricular contraction index: FS (Fractional shortening) = 0.25-0.42

The size of the mitral orifice is >16mm.

Size of the aorta: 20-37mm, a pulmonary artery on ultrasound.

Computer class cutting

With multi-layer computer tomography machines, reducing the imaging time < 1 second, it is possible to create images of the heart chambers and blood vessels in 2D, 3D, 4D and superior space. Both ultrasound and magnetic resonance are evaluated for the rate of calcification in the coronary arteries, which is useful for angioplasty or stenting.

Magnetic Resonance

Along with computed tomography, magnetic resonance imaging has also made new advances in imaging: faster, clearer, and especially software that allows for the reconstruction of multiple images of the heart chambers and blood vessels (MRA). , has replaced the classical methods of the cardiac chamber and vascular imaging.

In addition, the modern digital angiography method also helps in vascular intervention very effectively, avoiding major surgery.

Abnormal images of the heart shadow

Abnormalities due to correlation

Reversal of viscera: right heart.

Pneumothorax (1).

Mediastinal tumor, paramediastinal lung tumor (2).

Scoliosis (3).

Pleural adhesions (4).

Pulmonary fibrosis, atelectasis (5).

Obesity (6).

Too much in the gut (7).

Ascites (8).

Pregnant women (9).

(1), (2), (3), (4), (5): spinal lung diseases.

(1), (2): deformed heart.

(3), (4), (5): the heart is pulled.

 (6), (7), (8), (9): the heart is pushed. 

Small heart

When the ribcage is stretched, the heart is not resting on the diaphragm but in a suspended state. At that time, the longitudinal axis is almost parallel to the vertical axis of the body, which is called a teardrop heart, and the diameter of H decreases markedly. Seen in the following cases:

Asthma and emphysema: small heart in contrast to wide chest (en tonneau).   

Anemia and exhaustion (cachexia), small heart, small chest. 

Figure; Normal cardiac shadow (left), large chamber heart shadow (right).

Large heart

Nonpathological enlarged heart (nonpathological):

Seen in athletes requiring high exertion: cycling, rowing, speed running... This type is only instantaneous, after rest, the heart returns to normal, probably due to increased respiratory exertion. thoracic volume.

People who drink a lot of beer.

General pathological cardiomegaly:

During and after some infectious diseases such as diphtheria, typhoid, pneumonia, acute rheumatism, there is often acute myocarditis, sometimes turning to the chronic stage.

Pericarditis: triangular heart ball.

Cardiac disease with each chamber:

The shadow of the heart is changed due to direct damage to the heart valves or disease in other organs such as lungs, kidneys, liver, arteries. The sign of each chambered cardiomegaly is clearly indicated in the early stages, after a period of pathological and hemodynamic progression leading to total cardiomegaly, but it still bears the hallmarks of the chambers of the heart due to primary valve damage. Of course, to diagnose this is not easy and requires high experience, sometimes it must be combined with clinical and other test results such as Electrocardiogram, Hemodynamics, Color Doppler ultrasound for definitive diagnosis. determined.

Image: The heart shadow is completely large.