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CT angiography of the vessels of the upper extremities is necessary for diagnosing cardiovascular diseases at different stages of development. Since problems with peripheral vessels often cause pathology, angiography of the veins and arteries of the upper extremities is gaining popularity, making it possible to identify the disease at the beginning of its development.
The final visualization of this examination provides information regarding the functional state of deep and small vessels, and also helps to diagnose various other abnormalities.
Despite the fact that such a diagnostic format is somewhat more expensive than a standard ultrasound and x-ray, its result is much more informative. Detailed visualization reveals a picture of possible anomalies not only of large veins and arteries, but also of capillaries, which cannot be examined in any other way.
Indications and benefits
The standard time for diagnostics involving contrasting is no more than half an hour. This is much faster than a standard MRI can offer. The accelerated process is especially important for people suffering from the fear of closed space – claustrophobia. It is much easier for them to endure ten to fifteen minutes of being directly in the tomograph tunnel for a CT scan than to lie on an MRI for half an hour.
Even the widely advertised Doppler ultrasound is not able to compare with angiography in terms of information content. The first is extremely limited in the obtained data of the study area, while the upgraded version of CT provides a more detailed diagnostic picture. The latter guarantees the study of the state of not only the alleged lesion, but also neighboring vessels. In the future, this becomes the key to compiling an effective treatment program, based on even mildly expressed changes in the surrounding capillaries.
Against the background of the above possibilities, the list of main indications for this type of CT scan covers a larger number of suspected and already diagnosed ailments. So, with symptoms of atherosclerosis, a detailed three-dimensional projection allows you to identify the degree of narrowing of all vessels in different places of localization.
If a patient is found to have arterial constrictions, the length of which is several millimeters, then this is the first wake-up call. Also, the image will be able to convey the irregularities of the internal contours of the vessels, which also indicates the development of atherosclerotic disease.
Patients who have been suffering from vascular atherosclerosis for a long time, when prescribing the stage of contrasting, it is necessary to take into account the indicators of the state of the vessels, namely their lumen. The lower their percentage, the more advanced the disease. In the most severe forms of the disease, the contrast agent is not even able to get through the artery, and is looking for detours using capillaries.
The computer version of testing helps to find out if the patient has arterial thromboembolism or thrombophlebitis at any stage of development. With the help of modernized technology, it turns out:
- detect the location of a thrombus;
- set the clot size;
- determine the degree of narrowing.
All together, this becomes the basis for a verdict in favor of prescribing conservative treatment or surgery if the narrowing of the lumen has led to a complete blockage of the vessel.
An equally common reason for contacting a diagnostic room is open and closed injuries, which lead to damage to veins and arteries. If the deformation is confirmed, then the analysis will establish:
- place of transmission;
- lumen reduction indicator;
- break point.
In favor of the latter, the release of the contrast into nearby tissues will testify instead of continuing to move along the vascular bloodstream as usual.
Dissecting type aneurysm is considered to be another disease that encourages a doctor to send his patients for CT scans. Due to the detailed layered image, it will be easy to identify not only the location of the problem area, but at the same time the length of the bundle.
The found false channel will help in this for transporting blood with nutrients to the nearest organs. The hint must be sought in the flow of the contrast solution, which will additionally indicate the deformation of the arterial contours.
Also, monitoring the effectiveness of previously prescribed therapy is considered a common reason for the indication for examination. The data obtained will indicate whether treatment aimed at reducing the thrombus or atherosclerotic deposits has helped. The image will even tell the degree of normalization of the lumen after surgery when diagnosing vascular obstruction.
Contraindications for CT Angiography
Schematically, all contraindications for this study are divided into two broad camps: absolute and relative. The first group includes:
- pregnancy;
- exceeding the weight limit.
Moreover, pregnancy is an absolute ban at any time. Such categoricalness is explained by the fact that the fetus is sensitive to the slightest changes in the radioactive background. The dosage of X-ray exposure, which is completely safe for an adult, can affect the fetus in a negative way. Ignoring a medical prescription threatens to develop a mental or physical defect in the unborn child. Instead of exposing the fetus to potential danger, the doctor will send the pregnant woman for a safer ultrasound.
The contraindication regarding excess body weight has various variations, which are based solely on the characteristics of each individual device. Some models of equipment can only withstand weight up to 120 kilograms. But modern technology is increasingly designed for people weighing up to 200 kilograms. This question should be clarified in advance at the clinic before making an appointment.
But children’s age is considered a relative contraindication. Usually, research is contraindicated for children under 14 years of age, but the age period from 14 to 16 years is already included in the list of relative prohibitions. This means that in the case of the prevailing benefit over the harm of irradiation of a still developing organism, the doctor gives permission for the manipulation.
There is also a special list of contraindications, the decision on which is made on the spot. These include:
- individual intolerance to contrast;
- renal failure;
- lactation period.
All of them relate to the stage of contrasting, which requires the introduction of a special solution intravenously. In most cases, these are iodine-containing components. If the patient is allergic to this substance, and there is no way to replace it with a rarer analogue, the diagnosis is not carried out.
Sometimes the patient cannot accurately answer whether he is allergic to iodine components. To negate the risks of anaphylactic shock or Quincke’s edema, an X-ray laboratory technician performs an allergological test before manipulation.
Renal failure for standard computed tomography is not a contraindication, but due to the need to use contrast, people with this diagnosis have to refuse examination, as the kidneys do not have time to cope with the tasks assigned to them, which leads to the accumulation of drug toxins in the cells. It simply does not have time to be excreted naturally.
Due to the possibility of penetration of harmful components of the contrast into breast milk, it should not be used during lactation. If you can’t do without an examination, a woman should stop breastfeeding for at least two days after diagnosing the vessels of the upper extremities. Moreover, all 48 hours you need to periodically express milk and pour it out.
Sometimes the reason for refusing to perform a scan is a particularly serious condition of the victim, up to the onset of deep shock. Such people cannot control themselves, as well as those who suffer from mental disorders. And due to the fact that complete immobility is the key to clarity of visualization, the patient can cross out all the work with a careless involuntary movement.
Preparation and technology
The procedure does not require any special preparatory measures. The only important point here is the refusal to eat approximately four hours before the scheduled examination. It is also necessary to make sure that the patient’s clothing does not have any metal components.
In some private clinics, the patient is even offered drawstring cotton pajamas or disposable gowns to eliminate the risk of distorting the final images. After removing all jewelry and even metal dentures, you can go to the medical couch.
All examinations are carried out in a horizontal position. To simplify the task for the patient, it:
- the head is laid on a roller;
- fixed with straps;
- allow in case of an emergency to communicate via two-way communication with the X-ray laboratory assistant.
The last point is especially important for people with claustrophobia or those who, due to the increased nervous environment, are haunted by convulsive syndrome.
To accurately determine the area under study, the X-ray laboratory technician usually first takes several test shots, and only then injects a contrast agent. After that, the couch returns under the scanner, which constantly rotates and emits soft beeps.
The laboratory assistant will be able to announce the exact time of the procedure only on the spot. The reason for this is the different capabilities of the equipment. The smaller the step for shooting, the more time it will take to examine.
Approximate transcript
To get the deciphered conclusion in hand, you need to wait about half an hour or more. But often the results of the examination are immediately transmitted to the attending physician, who will be able to interpret the results to the patient.
If the patient was initially suspected of having a venous or arterial blockage, then the image as a confirmation of the diagnosis will demonstrate the absence of contrast spread along the usual channel. If such a deviation is detected and based on other test results, the patient’s history, a verdict of thrombosis, thrombophlebitis, thromboembolism is issued.
When the picture indicates a decrease in the lumen from 30% to 90%, this indicates that the risks of atherosclerosis, ischemia, vessel compression and arteritis increase significantly. Stenosis will tell you that a person may have a congenital pathology, or endarteritis.
An equally serious disease that is easy to detect with angiography is varicose veins or aneurysms, although it is generally accepted that varicose expansion is characteristic exclusively of the lower extremities. In the picture, they are manifested by the expansion of blood vessels, their tortuosity or protrusion of the wall.
Anomalies in the structure of the vascular network such as malformation are much less common. In the pictures, they can be seen if areas with anomalous branching are found. The same will be indicated by the flow of contrast into neighboring arteries or veins. Then the cavities surrounding the problem area will be filled with a chemical that is clearly visible.
Based on the data obtained, as well as other related information, the doctor will be able to draw up a treatment program taking into account the individual characteristics of a particular patient.