Computed tomography (CT) | Diseases and conditions: Medical tests.

What is a CT scan?

The computed tomography or CT, also known as scan or CT scan (computed tomography), is a diagnostic test that allows x-ray images of the inside of the body in the form of transverse cuts through the use of x-rays, or, if necessary, in the form of three-dimensional images.
In which cases is performed a CT scan or CT scan?
The most common reasons that the realization of a CT or computed tomography may be requested are as follows:
In the event of trauma to detect bleeding, lesions of the internal organs or fractures.
To diagnose tumors and see its possible extension.
To study diseases of the spinal cord or spinal column.
To diagnose certain infections.
To guide some interventions such as the taking of biopsies or drainage of abscesses.
On many occasions, it is necessary to manage a liquid called contrast, which tends to be a compound of iodine, and that highlights in images obtained with the TAC, which facilitates the interpretation of the test. This contrast medium is usually administered intravenously, although they may also administer via oral or rare times, in other ways.

Prior preparation for a TAC

If you will make you a TAC these are the issues that you must provide in advance:
Duration: the test is performed in a few minutes. What takes longer is undress and take a venous route when the administration of intravenous contrast injection is needed. If you perform an intervention as an outlet of biopsies or drainage of an abscess can last more.
Entry: the test can be done on an outpatient basis.
Is necessary to be accompanied?: don't have to be accompanied by, although it might help if it makes you feel more relaxed.
Drugs: is not necessary to take any prior medication.
Food: depends on the organ being studied, in general it is necessary to go on fasting if administer you a contrast.
Clothing: you can wear any clothes you want, but it should be easy to remove. You don't want to carry metal objects (earrings, bracelets, etc.), because they will be asked to remove them during the test.
Documents: should be informed consent, which is a role where they explain you what is the test and its potential risks. You should read it carefully and take it signed. It has to take the wheel of the test request.

Other considerations

The use of an anti-diabetic drug called metformin may be associated with severe side effects when administered with intravenous contrast. That is why, in some patients, particularly in patients with kidney, heart or liver, disease it should stop taking metformin before performing a CT with contrast and it may be necessary to monitor kidney function prior to reintroduce it.
It should be noted the technician the possibility of having allergies to iodine or the iodinated contrast, because it is a contraindication for the realization of a CT scan with contrast
Not exercising immediately before the test and be as relaxed as possible, because any movement can alter the result should

Contraindications of TAC

It should not be a TAC in the following cases:
If you have allergies to iodine or dye can be proof, but avoiding the administration of contrast.
The contrast by mouth is contraindicated in cases of suspicion of perforation of the digestive tract and prior to an endoscopy or surgery involving the digestive tract.
The use of intravenous contrast is contraindicated if there is renal or cardiac disease serious and in some tumors such as pheochromocytoma or myeloma. It is also contraindicated in the case of some diseases of the thyroid, as iodine which carries the contrast may be harmful for the thyroid.
Pregnancy is a contraindication for the test, with or without contrast.

The TAC during pregnancy and lactation

The TAC should be avoided in pregnancy, especially during the first quarter, because of the risk of radiation to the fetus. Breastfeeding in general is not a contraindication performing the test, even if administered intravenous contrast. The amount of contrast that can be excreted by the milk is less than 1% of the administered and the amount baby absorbed through the intestine is less than 1% of what they eat. Therefore, the amount that can reach the baby is so small that it is not recommended to stop breastfeeding to perform a CT scan with contrast.
However, those mothers who are concerned about the risk that you may have about your child this minimal exposure to contrast, can avoid breastfeeding during the 24 hours following the completion of the procedure. This is the time that it takes to eliminate all the contrast of the blood of the mother. During these 24 hours the mother can remove the milk through a pump and discard. In anticipation of this period that won't be breastfeeding, the mother can remove milk before testing and store enough to cover the needs of the child for 24 hours.

Procedure: how is a CT

The device which is a CT scanner or scanner, donut -shaped and inside moves a stretcher that is where lies down the patient, usually face up. The table moves on the inside hole of the scanner for a few seconds and then going doing multiple x-rays. Unlike MRI, this test does not usually cause claustrophobia, because the patient does not remain within a closed site. Noise is not heard.
In general, it is necessary to change the clothes by a hospital gown. If you perform a cranial CT it is generally not necessary to change clothes. They will make you take off all metal objects because they interfere in radiographic images.
In case that contrast is administered oral are given to drink previously tested a kind of porridge containing barium. If the contrast is intravenously they will pick up a venous pathway in the arm and introduced the contrast there moments before the shooting.
During the procedure, a technician will be watching him through a glass from an adjoining room and will instruct you that does not move. You can sometimes tell you that you do not breathe for a few seconds. At the end of the test, if they have administered contrast, can tell you to wait a few minutes in an adjacent room if an allergic reaction appear.
The TAC is a very safe test. The more severe reaction may be an allergy to the contrast oral or intravenous. The symptoms of this allergy can range from a feeling of heat and the appearance of a skin rash, to a very severe allergic reaction called anaphylactic shock. But quiet, there will always be a health care Manager to solve these rare eventualities. Allergy is often immediately after administration of contrast. However, very rarely, you may receive allergy hours after contrast administration, causing itching, difficulty swallowing or breathing. In such a case you should urgently contact a doctor.
The intravenous contrast sometimes gives some heat entering the body through the vein. When getting out of the vein during its introduction can cause local inflammatory reactions.
Intravenous contrast in rare cases can cause kidney failure. This was more frequent in the past with contrast media that is no longer used. On the other hand, the dose of radiation that is received in a TAC is very small and does not produce side effects.

Results of a CT scan

The images obtained by the CT scanner can be seen immediately. However, their interpretation requires much expertise and is carried out by medical radiologists. This specialist will make a written report that will give you a few days of the test along with the radiographic images obtained.
The result report will include data on the technique used, if it was necessary the use of contrast and the findings found. The type of discovery can vary greatly depending on the pathology and studied organ. Many times you can find tumors benign or malignant, signs that indicate various infections like abscesses or cavity in any organ, or pathology in the bones, such as fractures or malformations. In relation to the vessels that irrigate the various organs, you can find thrombus, vascular infarcts (due to the blockage of an artery) or bleeding. It is often necessary to repeat the test to see how to evolve different injuries either spontaneously or with treatment.
It is advisable to go to pick up the result and not assume everything is normal because the results you are not delivered in a few weeks. The doctor has asked the test will give you the results and will instruct you to need to make other complementary examinations or treatment.

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