If it is necessary to obtain reliable information about the quality and condition of the vessels supplying blood to the lungs and mediastinum, for example, with suspected heart defects, aortic aneurysms, pathological processes in the main vessels of the chest, specialists prescribe computed tomography of the thoracic aorta and pulmonary artery to patients.
During this examination, layer-by-layer scanning of the necessary areas of the body with x-rays occurs with the issuance of pictures of the actions taken. Thanks to three-dimensional images of the vascular system, doctors can diagnose the most minor changes in the intercostal arteries, the thoracic aorta, and branches of the pulmonary trunk.
Benefits of conducting this survey
The above vessels are very difficult to evaluate when using ultrasound or magnetic resonance imaging, since the direction of these methods is not designed to consider such structures along their entire length. That is why CT of the aorta and pulmonary trunk gives the most accurate and effective results that can be used to make accurate diagnoses and the subsequent appointment of therapeutic measures. X-ray angiography for vascular pathologies can provide some similarity to CT results, but specialists always insist on having CT scans to obtain more accurate data.
In addition, in order to conduct high-quality angiography, it is necessary to inject a contrasting drug directly into the study area, and since an injection cannot be made into the aorta, doctors have to pierce the femoral artery and pass a long probe through it to the mouth of the aorta, which makes the angiography procedure highly invasive. Moreover, if a computer tomography of the indicated area is performed, it will be sufficient to introduce a contrast agent into the ulnar vein. Due to such a scheme for introducing contrast, radiological angiography takes much longer in time than computed tomography, which creates another competitive advantage for the latter.
The main disadvantage of angiography is the fact that the entire process from the beginning of the introduction of contrast passes under fluoroscopic control, which significantly increases the patient's radiation dose. When conducting computed tomography, this effect of x-ray rays is not required, they affect a person for a very limited time and are also low-dose, ensuring absolute safety of patients.
Indications and contraindications for use
Among the main medical indications for computed tomography of the thoracic aorta and pulmonary artery, doctors distinguish the following diagnosed diseases:
- stratified aneurysm or thoracic aortic aneurysm;
- pulmonary embolism;
- coarctation of the aorta;
- stenotic changes in the pulmonary artery or aortic orifice;
- pathological conditions of the aorta or pulmonary artery;
- discovery of the Botallov duct;
- atherosclerosis of blood vessels.
However, when assigning this examination, it is important to understand that CT should not be performed for pregnant women. Although this category of patients may rarely need such a diagnosis, since women with pathologies of the cardiovascular system, before starting planning an unborn child, they are necessarily examined for the possibility of becoming pregnant.
Since this type of CT is not done without contrasting, it cannot be used for the group of patients who are allergic to the contrast agent or iodine, which is the basis of contrast. After contrast is introduced into the bloodstream, the iodine base of this substance stains the walls of the blood vessels, making the gaps between them more visible in the tomography images. Such staining details the embossed surface of the endothelium and allows you to evaluate its smallest defects.
Also a contraindication to this diagnostic method is renal failure, severe thyroid dysfunction, severe forms of diabetes mellitus, some forms of myeloma. All these conditions can not be a reason to refuse an X-ray examination, but a contrast medium in any of the above forms of diseases can be dangerous.
Contraindications for computed tomography are revealed at the appointment of the attending physician, but even in cases where this has not been done for some reason, specialists performing tomography in research centers are required to talk with patients before conducting studies and sometimes require some tests to be provided to make sure the safety of diagnosis for a particular person.
Preparation and diagnosis
Special preparation for computer angiography on modern equipment is not required. 5 hours before the proposed examination, it is necessary to refuse food intake, and somewhere an hour before the procedure, experts recommend not drinking anything. Such limitations require CT with contrast enhancement.
The patient must have a referral from the attending physician for a study, discharge or medical record, the results of previous studies, if any, analyzes. Before starting the diagnosis, a contrasting drug is administered to the patient. He is laid on the table of the tomograph and warned that with all the movements of the tomograph itself, a person should remain immobilized. The table itself will move horizontally, and the annular region of the apparatus will rotate around it.
During computed tomography, the patient remains in the room alone, and the specialist observes him through an X-ray-tight glass from an adjacent room. If necessary, you can always contact the clinic staff on a two-way basis. For patients, tomography is absolutely painless.
Sometimes patients are interested in why the doctor prescribes them to have a CT scan, and not magnetic resonance imaging. The fact is that the pulmonary arteries and aorta of the thoracic region are large vessels, in some areas reaching 3 centimeters in diameter, so for specialists they are more likely not soft tissues, but structures filled with fluids. Magnetic resonance imaging is not able to clearly visualize objects in motion, and in the case of vessels it is important to understand that they are pulsating, thus creating artifacts in MRI images.
At the same time, computed tomography allows in this area to obtain images instantly and with high accuracy of the displayed objects. Also, the diagnostic technique makes it possible to build 3D models from the obtained images and consider the necessary vessel from all sides. At the same time, during the CT scan, the specialist can also see other neighboring human organs, which helps to determine the cause of the disease in more detail.
The results of computed tomography are usually given to the patient in the form of a written opinion and all received images within half an hour after the end of the study. The patient must provide all these documents to his doctor, who gave him a referral for examination, in order to make the correct diagnosis and prescribe appropriate therapy.