Computed tomography – the most important information
Computed tomography – (CT or CT – computed tomography) is a a non-invasive diagnostic imaging procedure that uses ionizing radiation (X-rays) along with advanced computer algorithm technology to create images from inside the body. CT scans show detailed scans of any part of the body, including bones, muscles, internal organs or blood vessels.
In standard X-ray examinations, a beam of energy is directed at the part of the body being examined. A detector behind the X-ray tube captures changes in the energy beam after it passes through skin, bones, muscles and other tissues. Although much information can be gleaned from a standard X-ray, many details of internal organs and other structures are not available.
In CT, on the other hand, the X-ray beam travels in a circle around the body. This allows multiple images to be obtained from different angles. Information from the scan is sent to a computer, which interprets the data and displays it in two- or three-dimensional form on a monitor.
KT scans can be performed with or without “contrast.” Contrast refers to a shadowing agent injected intravenously, through a venflon inserted before the scan. This substance makes a particular organ, tissue or blood vessel more clearly visible. Examinations with a shadowing agent require fasting for a certain period of time before the procedure. For more information, please call our helpline.
How to prepare for a CT scan?
- REFERRAL: A CT scan, like any examination using ionizing radiation (e.g., X-rays), REQUIRES a valid referral for examination of a specific body part from a primary care physician or specialist.
- PRECAUTIONS: If you are pregnant or suspect you may be pregnant, contact your doctor before scheduling the test.
- CLOTHING: You may remain in your clothing during the examination, as long as it does not contain any metal parts or is not part of the examination (we don’t mind the zipper from the pants when examining the head OCT). Otherwise, we will ask you to remove the item of clothing in question and offer you an apron to cover yourself.
- CONTRAST: Contrast may be required during the examination. Contrast agents help the radiologist describe the examination and detect any disturbing structures in the body.Some patients should not be given iodine-based contrast agents. If you have kidney function or thyroid problems, please let us know in advance. We will determine together whether we can perform the examination without contrast agent or find an alternative imaging test.
In the case of an examination with a shadowing agent, it is necessary to determine creatinine levels and eGFR from blood in the diagnostic laboratory. This allows us to know how the patient’s kidneys are working and allows us to choose the optimal amount of shadowing agent, or to protect the patient’s kidneys from adverse effects of contrast. For those with thyroid disease, we ask that the thyrotropin hormone, the so-called TSH, be determined, which will help protect this organ as well, especially in those with hyperthyroidism of this gland.
- ALERGY: Please inform us if you have had an allergic reaction to any contrast agent. Intravenous contrast will not be given if you have had a severe or anaphylactic reaction to any iodine contrast agent in the past. Any known reactions to contrast should be discussed with your doctor.
- EATING/DRINKING: All of our patients are advised to be fasting at least 5-6 hours before a CT scan, as an allergic reaction after contrast administration can cause nausea and lead to vomiting. It is permissible to drink a moderate amount of water before the examination.
- CLAUSTROPHOBIA: The CT scanner resembles a doughnut with a hole in its shape, so don’t be afraid of being enclosed in a long tube – people suffering from claustrophobia praise the CT scan due to the relatively narrow width of the camera (in CT there is no feeling of “enclosing the body in a tunnel”).
- MEDICATIONS: All patients can take prescribed medications as usual.
Pursuant to Article 32c(2) of the Atomic Law, I would like to inform you that the activities involving exposure to ionizing radiation referred to in Article 4(1)(1) or (4-16) of the Atomic Law carried out by PPDiagnostics do not adversely affect human health and the environment.
Computed tomography – frequently asked questions(FAQ)
1. what is computed tomography (CT)?
Computed tomography (CT) is a medical imaging technique used in medicine to obtain detailed images of the inside of the body. CT machines use a rotating X-ray tube and a row of detectors to measure the attenuation of X-rays by various tissues inside the body. Measurements taken from different angles are then processed on a computer using computer algorithms to produce cross-sectional images, “slices,” of the body.
2. in what cases is a CT scan used?
CT scans are used in a wide variety of cases, such as.
- assessment of bone fractures,
- implant loosening,
- oncology diagnostics,
- search for cancerous distant metastases,
- gastrointestinal evaluations
- evaluation of vessels (especially arteries) in angio-CT,
- Control of hernias and cysts,
- Diagnosis of strokes and cerebral infarctions,
- as well as many others;
3. is the CT scan safe?
A CT scan carries very little risk of inducing cancer, since ionizing radiation (X-rays) is used to scan the patient’s body. Nevertheless, the clinical benefits of performing the test and diagnosing possible disease far outweigh the risk of cancer. Untreated disease will destroy a patient’s health faster than the minimal chance of a cancerous tumor.
4. how to prepare for a CT scan?
For each study, you should bring with you:
- ID,
- A referral (without it we will not perform the test!),
- Current (maximum two weeks) result of creatinine, eGFR and TSH (especially if the patient has thyroid disease)
- previous medical records pertaining to the area under study (hospital discharges, previous imaging studies, medical appointment cards, oncology history, etc.),
- Clothing without metal elements in the area tested,
Jewelry should be removed before the test.
If the test is to be performed with the administration of a contrast agent, the patient should not eat for 5h before the scheduled test.
5. do I have to stop taking my medications before the CT scan?
Each patient should take their medications as prescribed by their doctor.
6. am I exposed to radiation during the CT scan?
Yes, ionizing radiation (X-rays) is used to perform a CT scan.
7. is the CT scan painful?
The examination is completely painless. Some discomfort may be the insertion of the venflon (needed to administer the contrast agent), but the pain is minimal (as when drawing blood).
8. how long does a CT scan take?
The CT scan takes from a few minutes to a maximum of 15-20 minutes.
9. can I have someone with me during the CT scan?
Companions during the visit are always welcome, they are a mental support for the patient, and they also help the patient find his or her way through the stressful situation of having to undergo an examination. However, the companion remains outside the CT scan room for the duration of the scan so as not to expose themselves to unnecessary radiation. In the case of minors, it is possible for a parent to accompany the child during the examination, after putting on the lead apron, but only as a last resort.
10. can the CT scan be performed if I suffer from claustrophobia?
The CT scanner resembles a doughnut with a hole or a bagel, so the patient does not enter a long “tube” as in an MRI, but only a relatively wide opening. This allows virtually all people with claustrophobia to have the test, as there is no feeling of entering or being in a cramped space.
11. is a CT scan possible if I have metal implants?
Yes, CT successfully performs examinations with any implants in the body, scanning on CT has no effect on them. Also with electronic devices like pacemakers or hearing aids, a scan on CT can be performed without any problems.
12. What are the potential side effects of a CT scan?
If a patient suffers from hypersensitivity to iodine, he or she may experience some adverse effects when a contrast agent is administered, depending on the degree of this hypersensitivity. Due to the ionizing (X-ray) radiation used during CT, there is also a negligible chance of inducing cancer in the irradiated tissues.
13. How are the results of the CT scan interpreted?
Interpretation of diagnostic images is carried out by a radiologist. For each examination performed by us, we include a professional description made by a reputable radiologist. Such a description is the basis for the implementation of treatment, so the result obtained should be consulted with the doctor ordering the examination or a specialist dealing with the examined area / organ.
14. How long will I have to wait for the test results?
The waiting time for a description depends on many factors. Radiologists specialize in describing specific areas of the body, so the wait time for a description varies greatly – it depends on what area was examined. It is best to ask before or after the examination what the current wait time for description is.
15. will I have to pay additional costs for a CT scan?
As a rule, the price of the examination coincides with that indicated in the price list. The only additional cost that may arise is related to the need to administer a contrast agent (CPC). There are a number of examinations that are performed with contrast each time – then in our Laboratory it is included in the price, and the information about it is indicated in the price list. However, there are examinations that can be successfully performed without the administration of a contrast agent, but in the course of them it may turn out that in this particular case, for a complete and reliable diagnosis, the administration of contrast will be required. In that case, it is additionally charged. Each time the decision in this regard is made by the radiologist.
16. what is the comparison between CT and MRI?
Both methods are used for different cases. CT images bones better, can cover a larger area of the body more easily, and is a faster test than MRI. It also better images arteries in angiographic studies. MRI, on the other hand, is better at examining small organs (pituitary gland, prostate), is more sensitive in soft tissue studies, and better at imaging areas related to neurology (brain, spine, nerve plexuses).
17. are there risks associated with radiation exposure during a CT scan?
There is little chance (even negligible) of inducing cancer in the irradiated tissues. Nevertheless, the clinical benefits of performing the test and diagnosing the disease far outweigh the risk of possible cancer.
18. Do you hear any sounds or noises during the examination?
The CT scanner is definitely quieter than the one for MRI. During the examination, you can hear the rotation of the X-ray tube and detectors, as well as the moving of the table, but these are not bothersome noises.
19. is a contrast agent used before the test?
The contrast is administered intravenously to the patient during the examination. Like any medical substance, it carries a risk of adverse effects, but it is relatively small.
20. can the CT scan be performed in children and is it safe?
CT examination can be performed on both children and adults if they present the appropriate referral. We do not perform the test without a valid medical referral. As in the case of adults, there is a small chance that a tumor can be induced from healthy tissues, so such an examination is not performed without a clear reason. During the scan, we pay special attention to the radiation dose (as low as possible without compromising the quality of the examination), as well as to protect the parts of the body not covered by the scan with a lead blanket. At our facility, we do not undertake the test in the youngest children. The contractual limit, adopted by us, is the age of 10 years. This is due to the fact that younger children, are often unable to lie still during the examination. If the patient is less than 10 years old, the decision to perform the test is made on an individual basis, depending on the area to be tested and based on a discussion with the parents, who are able to determine whether their child will be able to lie still for a specific period of time.
21. can I eat and drink before a CT scan?
You can eat and drink before the test without using a shadowing (contrast) agent.
However, if contrast is likely to be administered, we ask patients to abstain from food for 5h before the scan. A moderate amount of water can be drunk.
22. are there any contraindications to performing a CT scan?
- Pregnancy (especially between the 3rd and 15th week of pregnancy)
- Suspected pregnancy
- Sensitization to iodine in case of examinations with administration of a shadowing agent (contrast)
- Kidney failure
23. can a CT scan be performed during pregnancy?
Pregnancy is a serious contraindication to CT. If there is a possibility, the patient is referred for other imaging studies (e.g. MR). The fetus in the womb is developing intensively, which makes it more exposed to ionizing radiation than an adult. CT scans are especially discouraged between 3 and 15 weeks of pregnancy.
There are cases where a CT scan must be performed, and the benefits to the health and life of the mother, outweigh the existing risks. In consultation with the patient’s referring physician, we will perform such an examination, taking care to protect the fetus as much as possible from radiation.
24. can I return to my normal activities immediately after the CT scan?
Yes, if the examination was performed without the administration of a contrast agent, the patient can leave the laboratory immediately and return to normal activity. However, if the contrast agent was administered, he must wait in our Laboratory for half an hour. If there are no noticeable side effects after this time, he can return to normal activities and driving. However, we recommend that she drink plenty of water to flush the contrast agent out of her system as quickly as possible.
25 Should I tell my doctor about my allergies or existing medical conditions before the CT scan?
Yes, you should inform the person performing the test about your allergies(especially to iodine!), and write about them in the medical questionnaire filled out before the test.