Generality
The angioTAC is the Computerized Axial Tomography with contrast medium that allows to study the blood circulation in the arteries and in the veins, the blood circulation of the most important organs of the human body and, finally, all the various anomalies and pathologies of a vascular character.
With a total duration of a few seconds, the angioTAC requires maximum immobility on the part of the patient; the body's movements, in fact, can alter the accuracy of the images provided by the instrument, thus distorting the entire diagnostic examination.
The risks of the angioTAC are connected to the dose of ionizing radiation, to which the patient is exposed during the examination, and to the contrast medium, which in some individuals is the cause of an allergic reaction.
Contraindicated in case of pregnancy, obesity, renal insufficiency and diabetes, the angioTAC provides images of excellent quality, which allow to better plan the treatment most suited to the patient's needs.
Short review of what the TAC is
TAC, or Computerized Axial Tomography, is a diagnostic procedure that uses ionizing radiation ( X-rays ) to create extremely detailed three-dimensional images of specific anatomical areas of the body (brain, bones, blood vessels, abdominal organs, thoracic organs, pathways respiratory, etc.).
The TAC equipment includes:
- The large donut-shaped scan unit, called gantry : it is the radioactive source;
- The generator;
- The support on which to place the patient (in general, is a sliding bed);
- An electronic processor;
- A command console for displaying three-dimensional images;
- A system for recording the acquired data.
In addition to the conventional CT (or classical or without contrast ), there is also the CT with contrast medium : the contrast medium allows to obtain richer and more detailed images of a particular organ or anatomical tissue and of the blood vessels.
The TAC is normally painless ; it can be slightly painful, when intravenous injection of the contrast medium is expected.
Nevertheless, it is in any case among the minimally invasive procedures, since the dose of ionizing radiation to which the patient is exposed is considerable.
What is the angioTAC?
AngioTAC is a diagnostic test that exploits the potential of Computerized Axial Tomography with contrast medium, to visualize the flow of blood and its possible anomalies within the vascular system of the human body.
One of the techniques of performing the so-called angiography, the angioTAC is a radiology procedure, exactly like all the other types of CT scans.
The interpretation of the images of the angioTAC belongs to a radiologist, who, if necessary, will advise the patient to discuss what has emerged with a specialist in the circulatory system (a vascular surgeon or a cardiologist).
What is angiography in short
Angiography is an X-ray diagnostic test, which allows visualization of certain vascular districts in order to study their morphology, course and possible alterations.
The practice of angiography always requires the use of a contrast agent, injected into the bloodstream.
Contrast medium for the CT scan
Generally, the contrast medium used for the angioTAC is radioactive iodine based.
The radioactive iodine-based contrast media are also called iodinated contrast media .
Indications
Doctors use angioTAC, mainly, to analyze blood circulation in body areas in detail, such as the neck, upper limbs and lower limbs, and in organs such as the brain, heart, lungs, liver, kidneys, pelvic gut (i.e., pelvis), bladder, etc.
What allows you to diagnose the angioTAC?
Thanks to the angioTAC, doctors are able to identify or diagnose:
- A thoracic aortic aneurysm or an abdominal aortic aneurysm ;
- A brain aneurysm, ie in the brain;
- Episodes of aneurysm in general;
- Congenital malformations of blood vessels (eg, arteriovenous malformations) or heart;
- The narrowing of the carotid artery due to the presence of an atherosclerotic plaque or a blood clot . This condition is one of the main causes of stroke ;
- The narrowing of the arteries of the lower limbs ( obstructive arteriopathy of the lower limbs ), due to the presence of an atherosclerotic plaque or a blood clot;
- Traumatic lesions in the blood vessels of the brain, thorax, abdomen, pelvis and extremities of the human body;
- Episodes of aortic dissection with thoracic or abdominal site;
- A coronary artery disease (a disease of the coronary arteries of the heart) and its severity;
- The episodes of pulmonary embolism ;
- Abnormalities in the flow of blood circulating within the various organs of the human body.
Other purposes
The angioTAC can also be used to:
- Guide vascular surgeons or interventional radiologists during blood vessel repair operations, for example through the application of a carotid stent ;
- Evaluate the complex network of blood vessels of a tumor, before the surgical removal of the latter;
- Thanks to the images it provides, planning the coronary bypass or coronary stenting surgical operations;
- Helping vascular surgeons or interventional radiologists in planning endovascular surgery, aimed at eliminating atherosclerotic plaques;
- Evaluate the outcome of stenting, coronary bypass or endovascular surgery.
Preparation
The angioTAC requires special preparation, based on which the patient must:
- Communicate to the doctor who prescribes the examination if he suffers from some allergy, in particular iodine, that is the chemical element at the base of the contrast agents used for the procedure;
- If you are a woman, tell your doctor if you are pregnant or suspect you are pregnant ;
- Tell your doctor if and what medications you are currently taking;
- Inform the doctor of any illness suffered in the last period and if he is suffering from some heart disease, diabetes, asthma, some kidney disease and / or some thyroid disease ;
- Take the exam without jewelry or clothing with metal parts, as these could interfere with the proper functioning of the diagnostic equipment.
If the patient does not comply with this preoperative rule, he is invited to do so just before the procedure begins;
- Go to the full fasting exam for at least 6-8 hours. This means that, if the angioTAC is scheduled on the morning of a certain day, the last meal must be the dinner of the previous evening.
How to behave in the presence of an iodized contrast agent?
For people with a proven allergy to iodinated contrast agents, the solution to this problem is to take appropriate steroidal drugs, with an antiallergic effect, approximately 12 hours after the angioTAC.
Possible delays in recruitment could cause the radiologist to postpone the diagnostic examination.
Procedure
First, at the invitation of a medical staff member, the patient must:
- Respond to a questionnaire related to your medical history,
- Wear a special coat instead of your clothes and
- Take off all the jewelery and other metal objects that it is wearing, for the reasons stated above.
Once all these operations have been completed, the patient is ready to take his place on the sliding bed of the angioTAC, which serves, at a later time, to position him inside the so-called gantry (see figure).
To lie correctly on the couch, the patient can count on the help of a member of the medical staff (in general it is the same person who previously questioned him about his medical history, measured his pressure and temperature, etc.); during his placement, the one who helps him also reminds him how he must "behave" during the examination and the importance that his immobility has, when the instrument is in operation.
Once the patient is lying on the couch with all the necessary comforts (pillows, blankets, earplugs, etc.), and ready to be introduced into the gantry, the radiologist doctor intervenes, who, with the collaboration of a professional nurse, performs the injection of the contrast medium necessary to the angioTAC.
The injection of the contrast medium usually takes place in a vein in the arm or hand ; the possible injection methods are two: through the classic syringe or through an automatic pump .
From after its injection, the contrast medium takes a few minutes to be distributed in all the various anatomical districts of the human body.
Once the time needed for the contrast medium to reach the vessels and / or organs of interest has elapsed, the introduction of the patient into the gantry and the subsequent phase, dedicated to the creation of three-dimensional images, can finally take place.
The creation of the images is very noisy: this explains the supply to the patient of earplugs or, alternatively, of a pair of headphones.
Remember that, while the instrument is in operation, the entire medical staff leaves the room where the patient and equipment reside, and moves to an adjacent room, where there are the gantry control console and the registration system for the data acquired. However, the patient is not really alone: in fact, he resides in a room with a loudspeaker and a camera, through which he can communicate with the outside in case of sudden necessity.
After the collection of the images necessary for a detailed evaluation of the vessels and / or of the organs of interest, the radiologist declares the angioTAC concluded and starts the operations of extraction of the patient from the gantry, an extraction in which the "usual" member deals of medical personnel already intervened several times, in the previous phases.
Getting up from the couch and getting dressed, the patient is ready to go home and to his daily activities, unless otherwise indicated by the radiologist.
The particularities of the angioTAC to the heart
If the angioTAC is intended to investigate blood flow within the coronary arteries of the heart, the aforementioned procedure also includes performing an electrocardiogram in real time (ie during the diagnostic examination).
What feelings does the patient feel during the procedure?
During an angioTAC, the patient may experience a slight sense of discomfort, when the doctor inserts the needle of the syringe or the automatic pump, necessary for the injection of the contrast medium; furthermore, immediately after the injection and for a maximum of a couple of minutes, it is very likely that you will notice a strange metallic taste in your mouth .
Patients with difficulty in remaining immobile may feel uncomfortable after a short time after the procedure; however immobility is a fundamental condition for the success of the exam.
Important note on immobility
During the angioTAC, the invitation to complete immobility also includes the retention of the breath, since even the smallest movements, deriving from the respiratory act, can distort the results of the examination.
How long is the angioTAC?
Since the collection of blood flow images begins, the angioTAC has a very short duration, in the order of seconds .
On what occasions does the patient have to wait before returning home?
If the angioTAC provides unclear images, the patient is forced, on the decision of the radiologist, to postpone the return home, to repeat the entire procedure.
How to encourage, at the end of the angioTAC, the elimination of the contrast medium
To aid the elimination of the contrast agent from the body, radiologist doctors indicate that they drink a lot of water .
If the patient adheres to this indication, he eliminates the contrast agent from his body within 24 hours.
risks
The angioTAC presents several risks; here is what these risks consist of:
- Patient exposure to a non-negligible dose of ionizing radiation . It is a fact that ionizing radiation is a factor favoring the development of malignancies, both malignant and benign.
Extent of risk: The dose of ionizing radiation emitted by the angioTAC to the coronary arteries is equivalent to 4 years of natural radioactivity. Comparing with a simple chest X-ray (X-ray), this exposes the patient to a dose of ionizing radiation equal only to 10 days of natural radioactivity.
With this, one does not want to demonize the angioTAC, but only wants to emphasize that its repetition is not recommended.
- Allergic reaction to contrast medium . It is a rare circumstance, which only affects predisposed patients. Almost always moderate and controllable with specific drugs, the most common symptoms of allergic reactions to the contrast medium are: hot flushes, nausea, strange tingling, hives and prolonged pain where there has been injection.
Contraindications
They represent a contraindication to the angioTAC:
- the state of pregnancy,
- a history of severe allergic reaction to an iodinated contrast agent,
- obesity (CT scans can support people weighing no more than 150 kilograms),
- renal insufficiency (whose presence prevents the correct elimination of the contrast agent)
- and diabetes .
In some situations, claustrophobia could become a contraindication to angioTAC .
Is breastfeeding a contraindication to the use of contrast media?
Breastfeeding is not a contraindication to angioTAC; however, for most doctors and those who produce iodinated contrast agents, breastfeeding is a practice not recommended in the first 24-48 hours following the exam.
Results
Depending on the severity of the patient's condition, angioTAC results may be available immediately or after a few days.
The main advantage of the angioTAC is the remarkable precision of the images provided.
Other advantages of the angioTAC:
- It is minimally painless, minimally invasive and very precise;
- Thanks to its high detection capacity, it could make the use of exploratory surgery superfluous;
- The images it provides guarantee greater precision during surgery;
- It also detects minimal narrowing of blood vessels;
- It is more detailed than a nuclear magnetic resonance angio (or angio-MRI);
- It is excellent in identifying coronary heart disease;
- It is faster and less invasive, and presents a lower risk of complications, compared to the so-called angiography with catheterization.
