Atlas of CT Anatomy of the Abdomen

Abdominal Computed Tomography

Abdominal computed tomography (CT) is a type of medical imaging procedure used to diagnose and monitor internal stomach issues, like cancer, bowel obstruction, and abdominal pain.

Radiographers suggest an abdominal CT scan to look for the following:

• Hernia
• Cause of a fever
• Kidney stones
• Appendicitis
• Cause of blood in the urine
• Cause of abdominal pain 
• Cause of abnormal blood test results
• Masses and tumors 
• Infections
• Injury

The medical procedure involves the use of a thin X-ray beam that rotates around the abdomen to produce three-dimensional medical images of internal organs.

An abdominal CT scan may help the physician diagnose the following medical conditions⁽¹⁾:

Cancer

• Renal pelvis or ureter cancer
• Hepatocellular carcinoma or liver cancer
• Pancreatic cancer
• Colon cancer
• Melanoma (skin cancer)
• Lymphoma (cancer of the immune system)
• Renal cell carcinoma (kidney cancer)
• Ovarian cancer
• Pheochromocytoma (cancer of the adrenal glands)
• Spread of cancers that began outside the stomach

Problems in the Liver, Gallbladder, or Pancreas

• Acute cholecystitis (gallbladder inflammation caused by gallstones)
• Cholelithiasis or gallstone formation
• Alcoholic liver disease
• Pancreatic pseudocyst (fluid buildup in the abdomen)
• Pancreatitis
• Blockage of bile ducts
• Pancreatic abscess

Kidney Problems

• Kidney stones
• Hydronephrosis (kidney swelling urine backflow)
• Blockage of the kidneys
• Kidney infection
• Kidney or ureter injury
• Polycystic kidney disease (fluid-filled cysts in the kidneys)

Other Medical Conditions

• Abdominal aortic aneurysm (inflammation of the abdominal aorta)
• Appendicitis
• Bowel wall thickening
• Crohn’s disease
• Abscesses
• Renal artery stenosis (narrowing of the artery)
• Renal vein thrombosis (clot formation in the renal vein)

Abdominal CT Scan Procedure

Before the Procedure

If the exam involves the intravenous injection of a contrast dye, the patient may not eat or drink for three hours before the procedure. Some physicians may administer the contrast dye orally or through an enema.

It is recommended to wear comfortable clothes and to leave any jewelry and valuables at home.

A radiology nurse or a technologist may ask the patient about their medical history before the procedure. The discussion should include any possible allergies that the patient may have.

During the Procedure

A radiologic technologist administers a contrast dye to the patient before the procedure. The dye helps produce better image quality by highlighting internal structures, making them more visible on the scan⁽²⁾.

The patient lies down on a narrow slate that slides inside the CT scanner. Have the patient lie on their back with their arms raised above their head.

The radiologic technologist should always be able to see and hear the patient during the whole procedure.

The patient must lie still during the exam because movement causes blurred images. The radiologic technologist may direct the patient to hold their breath for a short time for better image quality.

Once a patient is inside the CT scanner, the scanner’s X-ray beam rotates around the patient. Some modern spiral CT scanners are able to take medical images during the procedure without stopping.

A computer develops separate images, also called slices, of the abdomen. Medical imagery produced from a CT scan may be stored, viewed on a computer monitor, or printed on film. 

Three-dimensional models of the abdomen may be created by stacking the slices together.

An abdominal CT scan should take 15 to 30 minutes to perform⁽³⁾.

After the Procedure

After the short procedure, the patient may be allowed to eat and drink as normal. 

If the patient received an injection of contrast dye, they must drink six to eight glasses of water to help flush the dye out of their body.

The patient’s scan may be interpreted by a radiologist, who sends the results to the patient’s consulting physician. The results of the abdominal CT scan should be ready after 48 hours⁽⁴⁾.

Risks of Abdominal CT Scans

The risks associated with abdominal CT scans include radiation exposure, allergic reaction to the contrast dye, and kidney dysfunction caused by the dye⁽⁵⁾.

CT scans expose individuals to more radiation than regular x-rays. Several X-ray or CT scans may increase a patient’s risk of cancer over time⁽⁶⁾. 

However, one scan carries a small risk only, as most modern CT scan machines are able to reduce the patient’s exposure to radiation. It is recommended to discuss this risk with a medical professional before a patient undergoes the procedure.

Another risk linked to CT scan procedures is an allergic reaction to contrast dye. 

The most common contrast dyes contain the mineral iodine. Individuals with iodine allergy may experience nausea or vomiting, itching, sneezing, or hives if they receive this type of contrast dye⁽⁷⁾. 

To address this issue, a physician may recommend a different contrast dye or administer an antihistamine (anti-allergy).

After a CT scan, the kidneys work overtime to help remove the dye from the body. A patient must drink extra fluids after the procedure to help flush the iodine out of their body, especially if they have diabetes or kidney disease.

Rarely, the contrast dye may cause a life-threatening allergic reaction in patients⁽⁸⁾. If the patient feels any trouble breathing during the test, they should immediately inform their attending radiologic technologist.

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