How to Read an Abdominal & Pelvic CT

Abdomen & Pelvic CTs are one of the most commonly ordered exams in radiology and therefore one must be comfortable with reading these types of studies. Here we will discuss how to read regular CT A&P with contrast and without contrast as they follow the same patterns although non-contrasted studies will be more difficult to see certain details. More involves studies such as triple phase, liver protocol, adrenal protocol, etc. will be discussed in another article.

Search Pattern:

  • Developing a search pattern is always a critical part of interpreting a study. Below I will share my approach.

  • 1. Evaluate the visualized portions of the lower chest.

    • The lower chest is included in CT A&P studies because lower lung pneumonias, effusions or other pathologies can cause referred pain that is interpreted by the patient as abdominal pain and therefore evaluation of these areas must be performed.

    • Use lung window to evaluate each part of the lung. Then evaluate the heart.

  • 2. Evaluate the abdominal and thoracic soft tissues. Scroll through using a quadrant approach scrolling from top to bottom.

  • Now lets look at the abdomen.

  • 3. Starting with the liver you will want to scroll the liver using a 1/3 approach to evaluate each aspect of the liver. It is beneficial to change the window of the liver after your first pass and scroll through the liver again as subtle hepatic lesions can easily be missed poor windowing. Be sure to look at the intrahepatic biliary ducts while evaluating the liver.

  • 4. Evaluate the gallbladder & follow the common bile duct/biliary system to the duodenum and pancreas.

    • Common findings/pathology:

    • There is a wide array of GB sizes, you may feel some are very small or very large early on but as you read more scans you will get a feel for what is acceptable. Personally dilated GB are common than you’d expect but not something worth much to me.

    • Gallstones

    • Cholecystitis (GB wall thickening, peri-cholecystic fluid, inflammatory changes and stranding)

    • GB wall thickness

    • Biliary ductal dilation

      • CBD <6 mm is generally considered normal

      • CBD <10 mm is generally considered normal is patient is s/p cholecystectomy

      • Anything greater than this is considered pathologic

  • 5. Evaluate the spleen.

  • 6. Evaluate the pancreas. Notice that the tail of the pancreas can easily be seen while scrolling through the spleen. Trach the tail of the pancreas back toward the head.

  • 7. Evaluate the CBD. Follow

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