CT Scan of the Abdomen and Pelvis - With and Without Contrast
What Is a CT Scan of the Abdomen or Pelvis?
The abdomen and pelvis contain the digestive organs as well as the urinary, endocrine, and reproductive systems.
A CT scan of this area may be done to look for abscesses, tumors, kidney stones, infections, or the cause of unexplained abdominal pain.
Abdominal scans can be used to help a doctor pinpoint the location of a tumor before a biopsy is performed.
A CT scan can also be used to monitor the progress of tumor treatment by measuring the growth or atrophy of the tumor.
Notice: This article is meant to give you a broad overview of what you might expect if you undergo a CT scan, with a definition and description of terms and procedures. Although I have an AD in radiography and a diploma for CT and MRI, which includes hands-on practical application in CT, I cannot give medical advice! If you have more questions about your procedure, please speak to your doctor or the technologists who will be performing the scan. I hope this is helpful!
What Are Some Symptoms That May Prompt an Abdominal or Pelvic CT Scan?
- Unexplained abdominal pain and tenderness
- Nausea, vomiting, or severe or chronic diarrhea
- Unexplained fever
- Unexplained weight loss
- Urinary problems
- Bowel changes
- Trauma to the spleen, liver, kidneys, or other internal organs
- Screening for metastatic cancers
Why Is Contrast Used in a CT Scan?
The contrast makes it easier for the doctor to visualize different organs in the abdomen or pelvis. Contrast enhances the appearance of the specific organs, veins, or arteries the doctor wants to see. For example, contrast can be used to visualize the intestines, ureters, bladder, or pancreas.
Contrast is also known as "contrast dye," although there is no actual dye in it; it's only a substance that shows up very clearly on the scan.
If you are scheduled for an abdominal and/or pelvic exam with contrast, you will either drink an oral contrast, receive barium through a tube in the rectum, or have IV contrast injected through a vein.
What Is Oral Contrast?
The oral contrast used in CT scans will be either a barium sulfate drink or an iodine-based drink.
What the Doctor May Be Looking for with Oral Contrast:
- Bowel Obstruction
- Barium sulfate is a chalky drink, made with a natural mineral, that is similar to some stomach remedies such as milk of magnesia. You will be given two bottles of the barium contrast to drink.
- You will drink one bottle the night before your scan, the other the morning of the scan. This is done to ensure the upper and lower digestive organs are well coated with the barium contrast. You will be given detailed instructions on exactly when to drink the contrast when you pick up the contrast before your exam.
- If you are scheduled to have an exam requiring a barium enema, the enema will be administered at the clinic.
Diatrizoic Acid (Gastrografin)
- Diatrizoic acid is used in place of barium when a patient is allergic to barium or when there is a chance the intestines or stomach have been perforated. It is not as thick as barium sulfate, but it has an unpleasant taste that may be slightly masked with flavoring.
- Gastrografin will be given a few hours before the exam or, if delivered rectally, right before the exam.
CT of the Abdomen and Pelvis With Oral Contrast
What Is IV Contrast?
IV contrast is an iodine-based liquid that is injected during the exam into a vein or artificial port at a high flow rate. The contrast will then spread rapidly throughout all the vascular structures and organs in your body.
What the Doctor May be Looking for When Using IV contrast:
- Impaired urine or blood flow
Your doctor will order an abdominal or pelvic exam with IV contrast when he wants to get a detailed look at your:
- abdominal arteries or veins
- pancreas and other internal organs.
The doctor will consider your age and health before ordering an exam with IV contrast. You may have your blood drawn and analyzed beforehand to ensure you are healthy enough for the contrast.
When the contrast is injected, you may feel heat or warmth in the back of your throat. This sensation may spread down to your pelvis, making you feel as if you have wet yourself. You may also get a metallic taste in your mouth.
Tell the CT Tech or Your Doctor Immediately If You Experience These Symptoms After Receiving Contrast:
- Hives or itching red skin
- Difficulty breathing or swallowing
- Swelling of the throat
- Bluish skin color
CT Scan With IV Contrast
What is a CT Scan Without Contrast?
It is not always necessary to use contrast to see problems in the abdomen or pelvis. Contrast may actually obscure conditions or anatomy.
Contrast is not needed when looking at:
- renal calculi (kidney stones)
- the spine or bones of the pelvis
- the intestines, when constipation is suspected.
- retroperitoneal hematoma (blood clot behind the peritoneum).
When a person comes to the the emergency department complaining of abdominal pain, many doctors will first order a CT scan without contrast to rule out severe constipation or appendicitis.
What Happens When You Get Scanned (Step-by-Step)
- After checking in for your exam, you will be asked to remove your shirt, pants, and any piercings that may interfere with the CT image. If you are to receive IV contrast, you may have an IV needle inserted at this point.
- You will then be taken to the CT exam room where you will see the actual machine. It is large, with a donut-shaped gantry and a long table that will move you in and out of the gantry.
- You will be asked to lie face up on the table with your head facing away from the hole. If you are to receive IV contrast and haven't been prepped yet, you will be hooked up to the IV at this point.
- The CT technician will explain what will happen and what you may experience. She will remind you that she will be able to see and hear you at all times.
- You will be asked to rest your arms above your head, and then you and the table will be moved into position toward the gantry. You will only advance as far as mid-chest; your head will still be outside the machine.
- The tech will leave the room and start the machine, which will make noise as the internal parts spin around you and the table.The machine will tell you to hold your breath as the table moves you out of the gantry. The machine will stop its backward movement, you will be told you can breathe again, and then the table will move you back to your original position in the gantry.
- There will be a delay as the technician makes adjustments in the control room. Depending on how the doctor ordered the exam and whether you need IV contrast, you will move in and out once or twice more.
- That's it! You're done. The table will move you out of the gantry and the tech will have you sit up. The IV needle, if any, will be removed and you will be reminded to drink plenty of fluids if you have received oral or IV contrast.
- If you are taking certain medicines, you will be reminded not to take them for 48 hours.
Why Won't the CT Tech Give Me the Results of My Scan?
Many patients get frustrated with x-ray, CT, and other technicians because the techs will not tell the patients what the images reveal. There is a reason for this. Technicians are not trained to diagnose medical diseases or conditions; they are trained to use imaging equipment properly to obtain diagnostic-quality images.
While technicians are in fact able to identify many diseases and conditions, they are forbidden to discuss what they see with the patient. Only a doctor with many years of training should look at the images to make a diagnosis.
The images will be read by a radiologist, who will make a diagnosis. Your doctor will be notified, usually within 48 hours, and you will be contacted with the results. If the radiologist sees a condition that could be life-threatening, the reporting process will be much faster.
- What Happens When You Are Scheduled for a CT Scan - Detailed information about what happens before, during, and after a CT scan.
- Contrast Dyes Used in CT Scans - In-depth information about the contrast used in CT exams.
Abdominal CT Scan - Article from the University of Maryland Medical Center. Includes a section called "What Abnormal Results Mean," with links for more information.
© 2013 Gable Rhoads