A Computed Tomography (CT) scan uses X-rays and computer processing to create detailed cross-sectional views, or “slices,” of the body’s internal structures, offering a clearer picture than traditional X-rays. A CT abdomen and pelvis with contrast specifically focuses on the internal organs, bones, soft tissues, and blood vessels within these regions, aiding medical professionals in investigating various conditions.
Understanding Contrast Material
Contrast material, sometimes called “dye,” is a substance used in medical imaging to enhance the visibility of specific organs, blood vessels, or tissues during a CT scan. It works by making certain areas appear brighter on images, allowing for a clearer distinction between normal and abnormal structures. For an abdomen and pelvis CT scan, contrast material is typically administered in two common ways. Intravenous (IV) contrast, often iodine-based, is injected into a vein, usually in the arm. Oral contrast, which can be barium-sulfate or other solutions, is consumed as a drink.
Purpose of the Scan
A CT abdomen and pelvis with contrast provides detailed images for diagnosing and monitoring various medical conditions. For example, it is commonly used to diagnose causes of abdominal or pelvic pain. The scan aids in detecting infections such as appendicitis, diverticulitis, or abscesses, and can also reveal inflammatory bowel diseases like Crohn’s disease or ulcerative colitis. This imaging technique is also valuable for finding and monitoring cancers affecting organs like the liver, kidneys, pancreas, and bladder, as well as detecting kidney and bladder stones. Furthermore, it can assess vascular issues such as abdominal aortic aneurysms or blood clots and identify internal injuries following trauma.
Preparing for Your Scan
Preparation involves several steps. Typically, you will be asked to fast, meaning no eating or drinking, for a few hours before the scan, often four to six hours, though clear liquids may be allowed up to two hours prior. Staying hydrated before the scan is generally recommended. You may also need to drink an oral contrast solution at home or upon arrival, which helps to coat the digestive tract.
Inform the medical staff about any allergies, especially to iodine or any previous reactions to contrast materials. If you have diabetes or kidney conditions, or if you are taking metformin, your doctor may provide specific instructions, as kidney function needs to be assessed, often through a recent blood test. Metformin may need to be temporarily stopped before the scan and for a period afterward, usually 48 hours, particularly if kidney function is reduced, to minimize the rare risk of lactic acidosis.
What Happens During the Scan
Upon arrival, you will change into a hospital gown and remove any metal objects, such as jewelry, that could interfere with images. An intravenous (IV) line will be inserted into a vein, usually in your arm, to administer the contrast material. During the injection of the IV contrast, many people experience a warm, flushed sensation throughout their body, and sometimes a metallic taste in their mouth. This sensation is normal and generally subsides quickly.
You will lie on a narrow table that slides into the center of the CT scanner, which is a large, donut-shaped machine. A technologist will be in an adjoining room, able to see and hear you, and will communicate instructions through an intercom. During the scan, remain very still, and you may be asked to hold your breath for short periods to prevent blurred images. The scan itself is usually painless and typically takes between 10 to 30 minutes.
After Your Scan and Potential Considerations
After the CT scan, you can resume your daily activities. If you received intravenous contrast, you will be advised to drink plenty of fluids, such as 8 to 10 glasses of water, over the next 24 hours. This helps to flush the contrast material out of your body through your kidneys. The contrast is generally excreted within 12 to 24 hours, assuming normal kidney function.
The results of your scan are usually sent to your referring doctor within one or two days. A CT scan involves a brief exposure to ionizing radiation. The amount of radiation from an abdomen and pelvis CT scan typically ranges from 10 to 20 mSv, which is comparable to about three to seven years of natural background radiation exposure. While the benefits of accurate diagnosis generally outweigh the small risks, medical professionals use the lowest radiation dose necessary. Side effects from contrast material are rare, but can include mild allergic reactions like itching or a rash, nausea, or a headache. More serious reactions are uncommon, and medical staff are prepared to manage them.