Introduction:
An abdominal computed tomography scan is used to detect the abdominal structures such as the liver, kidneys, spleen, intestines, bladder, pancreas, adrenal glands, bones, blood vessels, and lymph nodes. A computed tomography scan is more commonly known as a CT scan or CAT scan.
How Does a Computed Tomography Scan Work?
In a CT scan, a narrow beam of x-ray circles around the part of the body. It provides a series of images from different angles. A computer uses these images to create cross-sectional images called slices (2D images). This process is repeated to take a number of slices. The computer arranges these slices to get detailed (3D) images of the organs, blood vessels, and bones.
What Is the Role of Contrast Materials in CT Scans?
In CT scans, dense structures such as bones can be easily seen. But soft tissues may look faint in the images. Contrast materials are used to show them clearly in the images. They make the soft tissues look white on the scan. Contrast materials may be given in the following ways:
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Injection - Contrast materials may be injected directly into the veins. It is useful for scanning blood vessels, liver, and gallbladder.
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Orally - Drinking the liquid containing contrast material enhances the images of the digestive system.
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Enema - During the intestine scan, the contrast material may be inserted into the rectum.
What Are the Uses of an Abdomen CT Scan?
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Infections such as appendicitis (inflammation of the appendix) and pyelonephritis (kidney infection due to bacteria).
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Inflammatory bowel diseases such as Crohn's disease (inflammation of the digestive tract), ulcerative colitis (swelling of the large intestine and rectal lining), pancreatitis (inflammation of the pancreas), or liver cirrhosis (a liver disease that replaces healthy tissue with scar tissue).
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Abscesses (collection of pus within the tissues).
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Cancer of the liver, kidneys, ovaries, pancreas, and bladder.
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Lymphoma (cancer of the lymphatic system).
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Diverticulitis (swelling or infection of the pouches in the intestine).
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Kidney and bladder stones.
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Abdominal aortic aneurysms (AAA) are the enlargement of the main blood vessel supplying the body at the level of the abdomen.
Abdomen CT scans are also used for:
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Fine-needle aspiration cytology (FNAC) and biopsy procedures - By guiding the correct placement of needles/scalpels during the procedure.
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Assess the results of the surgery, such as organ transplants.
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Stage, plan and administer radiation therapy for cancer and assess the response of chemotherapy.
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Guides the treatment procedure, such as abscess drainage.
How Do You Prepare for Your Abdomen CT Scan?
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If your scan needs contrast material, you should not eat or drink anything for about 4 to 6 hours before the scan.
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Tell your doctor about your medical conditions and your regular medicines.
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You should not wear jewelry, eyeglasses, hearing aids, bras with metal underwires, dentures, or hairpins which may affect the quality of the image.
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Tell your doctor if you have had any allergies or allergic reactions to contrast material previously.
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If you are diabetic, you may be instructed to stop taking metformin or related medicine for at least 48 hours after the administration of contrast material as it may cause metabolic acidosis (increased buildup of acid in the body).
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If you have diabetes or kidney disorders, you may be asked to take a blood test before the day of the scan.
What Are the Factors to Pre-consider in an Abdomen CT Scan?
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Pregnancy- Radiation exposure in pregnant women, may cause birth defects in the fetus in the womb.
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Kidney Diseases- Inform your health provider if you are having kidney failure or disorders, as the contrast material may worsen your condition.
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Claustrophobia - Afraid of closed spaces.
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Breastfeeding- Breastfeeding mothers should avoid feeding for about 24 hours after the scan if they receive the iodinated contrast materials. The contrast material may pass through the breast milk.
How Is the Abdomen CT Scan Taken?
You are asked to wear the hospital gown and lie on your back on the narrow table in the scanner. Your technician may use a pillow or straps to hold you in a required position. Children who cannot hold long may require sedation. Some scanners are fast enough to scan children and don't require sedation. Parents or caretakers of the children may be allowed to stay in the room when the children are not comfortable. But they have to wear a lead apron to prevent radiation exposure. Movement during the scan may affect the quality of the images. Sometimes you may require contrast materials which depend on the type of the exam. The contrast materials may be swallowed or injected through an intravenous line (IV). You may feel warm throughout the body when the dye passes into your veins. After that, the technician uses the remote control from a separate room to move the table into the CT machine. Your table will slide into the center of the scanner.
After determining the correct position, the table slowly moves through the scanner for scanning. You will most likely go through the machine several times. Depending on the type of CT, you may be asked to hold your breath for a few seconds to get better images. Any motion, including breathing and body movements, may lead to artifacts on the images. After finishing your scan, you may be asked to wait until your technician reviews the images to make sure the images are clear enough to read by the doctor. You can continue your regular diet and activities after the scan.
What Are the Side Effects of an Abdomen CT Scan?
The side effects of an abdominal CT are mostly caused by the contrast materials used. But they are often mild.
Side effects of barium contrast are:
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Diarrhea.
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Nausea (urge to vomit) or vomiting.
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Constipation.
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Abdominal cramping.
Side effects of iodine contrast are:
Some of the severe symptoms of contrast materials are:
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Difficulty in breathing.
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Rapid heart rate.
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Low blood pressure.
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Swelling of the throat or other body parts.
What Are the Factors Affecting the Abdomen CT Scan?
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Barium (a liquid you swallow that helps to see your upper gastrointestinal tract) in the intestines from a recent barium swallow study.
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Presence of stool or gas in the bowel.
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Metallic objects such as surgical clips within the abdomen.
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Total hip replacement.
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Artifacts - Misrepresentation of tissue structures.
What Are the Limitations of an Abdomen CT Scan?
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Overweight - A person who is very large may not fit into the conventional CT scanner (450pounds).
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Gallstones - Abdomen CT can help diagnose gallstones, but comparatively, it is better to do an abdomen ultrasound.
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Acute Abdominal Conditions in Babies - Conditions such as vomiting or blood in the stool in babies may require alternate imaging techniques.
What Are the Risks of an Abdomen CT Scan?
CT scan produces ionizing radiation. Ionizing radiation may damage your DNA and lead to cancer. But risks are very less. The risks of developing fatal cancer in CT scans are about 1 in 2000. The risk may increase with every CT scan in a lifetime. Ionizing radiation is more harmful to children as they are growing. You should talk with your doctor about the benefits and potential risks of CT before the scan.
Conclusion:
An abdomen CT scan is a fast and accurate imaging technique of abdominal structures. It is a minimally invasive and painless diagnostic technique. In emergency conditions, it can reveal internal injuries and bleeding quickly, which can save many lives. An Abdomen CT scan provides detailed information about a specified area when compared to abdominal x-rays.
