Abdominal CT Scan: What’s Diagnosed?

Healthcare providers use abdominal computed tomography (CT) scans to diagnose various diseases and conditions, including cancer, blood clots, kidney or bladder stones, ulcerative colitis, and certain infections. Abdominal CT scans are also used after traumatic injuries to visualize abdominal organs, with or without contrast dye.

This article discusses the various uses for abdominal CT scans, what to expect when you get one, and how to interpret the results.

What Do Abdominal CT Scans Show?

Abdominal CT scans are a specialized imaging study used to evaluate multiple diseases and conditions, including:

• Blood system disorders (e.g., blood vessel aneurysms and blood clots)
• Kidney stones
• Abdominal abscesses
• Inflammatory bowel disease (e.g., Crohn's disease or ulcerative colitis)
• Traumatic injuries
• Different types of cancer (e.g., liver or kidney cancer or lymphoma)
• Underlying causes of acute or sudden onset abdominal pain (e.g., appendicitis, small bowel obstruction, or mesenteric ischemia)

Advanced trained healthcare providers also use abdominal CT scans to perform specific specialized procedures, including:

• Guided biopsies (extraction of small tissue samples for further evaluation)
• Draining abscesses
• Planning and assessing postsurgical results, such as organ transplants
• Staging and identifying proper administration of radiation treatments for tumors or monitoring chemotherapy response

What Abdominal CT Scans Don’t Show

Abdominal CT scans are not always the optimal imaging choice. A healthcare provider should do a thorough physical examination and take a comprehensive medical history to determine if an abdominal CT scan is the appropriate imaging choice.

Some examples of conditions in which an abdominal CT scan would not be used include:

• Cholecystitis (bile trapped in the gallbladder)
• Ectopic pregnancy (pregnancy outside the uterus)
• Intrauterine pregnancy (pregnancy inside the uterus, as is typical)
• Ovarian torsion (ovary twists around the ligaments holding it in place)

How an Abdominal CT Scan Works

After obtaining a comprehensive medical history and performing a physical assessment, a healthcare provider will determine whether you need an abdominal CT scan. Once a provider orders your abdominal CT scan, the provider's office will schedule the scan appointment.

Before the Scan

Before your abdominal CT scan, the provider's office will give you with specific instructions. They'll likely advise you to avoid eating or drinking before the exam. You'll also be instructed to wear loose, comfortable clothing and leave your jewelry at home. If the provider has ordered an oral contact, you might be asked to arrive a couple of hours before the exam.

Day of the Scan

On the scan day, you'll arrive at the provider's office and change into a hospital gown. The technologist will escort you to the CT table. They will secure you into position—usually on your back—with pillows or straps to ensure you are positioned for optimal imaging.

If you are having an abdominal CT scan with contrast, the technologist will administer it. The CT table will move back and forth to help identify the specific area to focus on and move slower once the CT scan starts. The total time for most CT scans is less than 10 minutes.

Once the CT scan is over, the technologist will have you remain in position. At the same time, the radiologist quickly reviews the images to ensure they are of appropriate quality for the viewing examination.

With Contrast Dye

Contrast dye is often used with abdominal CT scans to help differentiate organs from tumors or lesions. Contrast dye is also useful in detecting injury to blood vessels. Types of abdominal CT scans that would use contrast include those evaluating the following:

• Trauma to tissues or organs of the abdomen
• Bowel inflammation or diseases (e.g., Crohn's disease or diverticulitis)
• Infections, such as appendicitis or abscesses with suspected blood vessel involvement
• Intestinal blockages (e.g., small bowel obstruction)
• Identification of tumors, benign and cancerous
• Staging of cancerous tumors

Without Contrast Dye

Abdominal CT scans can be done without contrast dye. Examples of abdominal CT scans that do not require contrast include those looking for the following:

• Nephrolithiasis or detection of kidney stones
• Suspected spinal trauma
• Abscess, as long as there is no suspected injury or blood vessel involvement 

Understanding Abdominal CT Scan Results

Abdominal CT scans are complex imaging studies. A specially trained healthcare provider, a radiologist, supervises the process and reviews and interprets the images. After completing the interpretation, the radiologist will send an official report to your healthcare provider to review the results and work with you to develop a collaborative treatment plan.

Abdominal CT Scan Radiation Risk

Abdominal CT scans are an advanced imaging study that uses ionizing radiation. Ionizing radiation has been associated with increased cancer risk. Although the ionizing radiation from an abdominal CT scan is higher than plain film X-ray studies, such as a chest X-ray, the increased cancer risk is relatively small.

To protect from unnecessary radiation exposure, the CT scan technologist will minimize radiation exposure. CT scans generally take less than 10 minutes which also helps reduce radiation exposure.

Risk of Abdominal CT Scan With Contrast Dye

Contrast dye is a substance administered orally, rectally, or intravenously. Contrast dye can cause an allergic reaction. Factors that increase the risk for contrast reactions include:

• Multiple drug allergies
• Asthma
• Previous anaphylactic reaction to any medication

Contrast dye is cleared out of the body through the kidney's filtering process, so providers should ensure you have adequate kidney function before recommending a contrast dye abdominal CT scan. Many imaging centers will assess kidney function by drawing blood and analyzing it. If your kidney function is not optimal, they may consider alternative options.

Summary

Abdominal CT scans are a diagnostic tool for identifying infections, inflammation, injury, or cancer in the abdomen or pelvis. A provider might use contact dye depending on the rationale for ordering an abdominal CT scan. Abdominal CT scans are typically quick, lasting about ten minutes. After a radiologist reviews your results, they will send them to your primary care provider, who will review them with you to determine the next best steps to develop a collaborative treatment plan.