To analyze structures inside your body, medical practitioners utilize computed tomography, generally known as a CT scan. A CT scan creates images of a cross-section of your body using X-rays and computers.
It captures photographs of your bones, muscles, organs, and blood arteries in very tiny "slices" so that healthcare specialists may observe your body in exquisite detail.
X-ray machines that employ a fixed tube to point X-rays at a particular place are known as traditional X-ray machines. X-rays are absorbed in varying amounts by different tissues as they pass through the body. Against the black background of the film, higher density tissue produces a whiter image than other tissues.
X-rays produce two-dimensional pictures. A doughnut-shaped tube circulates the X-ray 360 degrees around you during a CT scan. The information gathered provides a detailed 3D image of your body's interior.
Difference between a CT scan and a CAT scan
CT scans and CAT scans are both terms for the same imaging procedure. The abbreviation CAT scan refers to computerized axial tomography.
What is the difference between a CT scan and a CT scan with contrast?
A contrast agent may be used during your scan. This contrast agent, often known as a dye, enhances photographs by highlighting specific characteristics.
Depending on the type of CT scan and the reason for the scan, your healthcare professional will either have you drink a specific liquid containing the contrast agent or give you an IV injection with the contrast agent, or both.
The contrast agent is excreted from your body through your urine during the next 24 hours, initially quickly and then more slowly.
Contrast Material
Some CT scans require a special dye called contrast material to assist in emphasizing the areas of your body being studied. The contrast substance absorbs X-rays and shows white on images, making blood arteries, intestines, and other structures stand out more.
It's possible that you'll be offered contrast material:
- Via the mouth.
You may be asked to consume a liquid containing contrast material if your esophagus or stomach is being scanned. This beverage may have an unpleasant flavor. - Through injection.
To make your gallbladder, urinary tract, liver, or blood arteries shine out on the images, contrast chemicals might be injected into a vein in your arm. During the injection, you can feel warm or have a metallic taste in your mouth. - Via enema.
To aid view your intestines, a contrast material may be injected into your rectum. This technique may cause you to feel bloated and uneasy.
What to do before a CT scan?
Instructions on how to prepare for your CT scan will be given to you by your healthcare practitioner. On the day of the exam, keep the following in mind:
- Arrival: Depending on your healthcare provider's advice, you should arrive early. Arriving early ensures that the testing is completed on time.
- Diet: For four hours before your exam, don't eat or drink anything.
- Medications: Check with your doctor to see whether you should take any of your regular medications before the CT scan.
- Comfort: Make sure you're dressed comfortably. Before the exam, you may need to change into a gown and remove your watch and jewelry, as well as any piercings you can remove. Dentures and hearing aids may also need to be removed. Metal items and zippers can hinder the scan.
If your CT scan involves the use of dye or contrast, your doctor may offer you some special instructions on how to prepare:
- Blood test: A blood test may be required before your CT scan. The blood test ensures that the healthcare provider selects the correct dye.
- Dietary restrictions: For the four hours leading up to your CT scan, you must watch what you eat and drink. When receiving contrast dye, it is best to drink only clear liquids to avoid nausea. Broth, tea or black coffee, strained fruit juices, plain gelatin, and soft beverages like ginger ale are also acceptable.
- Allergy medication: If you are allergic to the CT contrast agent (which contains iodine), you may need to take a steroid the night before and the morning of your procedure, as well as an antihistamine like Benedryl. If these medications are needed, consult with your healthcare practitioner and have them order them for you. Contrast agents for MRI and CT are not the same; if you are allergic to one, you are not allergic to the other.
- Preparation solution: Follow your technologist's or nurse's instructions for drinking the oral contrast solution.
What happens in the course of the test?
You will lie on your back on a table during the test (like a bed). A healthcare provider may inject the contrast dye intravenously if your test demands it (into your vein). You may feel flushed or have a metallic taste in your mouth after using this dye.
When the scan first starts:
1. The scanner's doughnut-shaped bed progressively advances into it. Because movement can generate blurry photos, you'll need to stay as motionless as possible at this point.
2. The scanner captures images of the region that the healthcare provider requires. A CT scan, unlike an MRI scan, is completely silent.
3. When the exam is over, the table exits the scanner.
What is the duration of the test?
In most cases, a CT scan will take around an hour. The majority of that time is spent on preparation. The scan itself should take no more than 10 to 30 minutes.
You can normally continue your normal activities whenever a healthcare expert indicates it's safe to do so - usually after the scan has been completed and clear images have been verified.
How long do you think it will take for the findings to appear?
The scan findings normally take 24 hours to arrive. A radiologist, a physician who specializes in reading and interpreting CT scans and other radiologic images, will examine your scan and write a report that explains the findings. Healthcare providers in an emergency setting, such as a hospital or emergency department, frequently receive results within an hour.
You will either have another appointment or receive a call after a radiologist and your healthcare practitioner have evaluated the results. The results will be discussed with you by your healthcare professional.
What may a CT scan reveal?
A CT scan will be ordered by your healthcare professional to aid in the diagnosis of your health. Providers can use the scan to evaluate bones, organs, and other soft tissues, as well as blood vessels and worrisome growths. The following are examples of what a CT scan can reveal:
- Cancer and benign (noncancerous) tumors of various sorts.
- Bone fractures (broken bones).
- Coronary artery disease.
- Clots in the blood.
- Irritable bowel syndrome (blockages, Crohn's disease).
- Injuries or illnesses of the brain and spinal cord.
X-rays can also reveal organs and tissues to healthcare experts. Body structures, however, appear to overlap on X-rays, making it difficult to discern everything. For a clearer perspective, the CT scan displays voids between organs.
Is it safe to have a CT scan?
CT scans are typically regarded as safe by healthcare experts. Children's CT scans are also safe. Your CT technician may use machines designed specifically for children to decrease their radiation exposure.
CT scans, like other diagnostics, acquire images with a small quantity of ionizing radiation. The following are some of the hazards linked with CT scans:
- Cancer risk: Any sort of imaging that uses radiation, such as X-rays, increases your risk of developing cancer by a small amount.
- Allergic reactions: The contrast agent might cause moderate or severe allergic reactions in certain patients.
Speak with your healthcare professional if you have any questions regarding the health hazards of CT scans. They'll talk about your worries with you and assist you in making an informed decision about the scan.
Is it safe for me to have a CT scan while I'm pregnant?
You should inform the CT technician if you are or may be pregnant. Although CT scans of the pelvis and abdomen can expose the unborn infant to radiation, the dose is not high enough to harm the baby.