Mr. Gossman is a 55-year-old gentleman who was marching in a bagpipe band when he was struck by a beer truck. On arrival to the emergency department he is complaining of abdominal pain. He is hemodynamically stable with diffuse abdominal tenderness. The remainder of his exam is unremarkable.
Based on your evaluation you believe that it is safe to proceed with a CT scan.
1. Who should you talk to before ordering the CT?
2. Should this patient get oral contrast and/or intravenous (IV) contrast?
3. After the CT is completed, is there anything that you do before reviewing the film with radiology?
4. What window should you use to look for free air?
5. In this patient, what does a fluid collection of 40 Hounsfield units (HU) most likely represent?
Ordering and Interpreting a CT Scan of the Abdomen: The Basics
As an intern in general surgery, you will often be asked to “pull up” the CT of the abdomen. Although no one expects you to become the expert on reading abdominal CTs in your first year of residency, your ability to understand the basics of ordering and interpreting a CT can help save a patient’s life.
Knowing when (and whether) to order a CT scan is an important skill to acquire during your internship.
The two rules of thumb are:
Do not order a CT without talking to your senior resident first. This rule is not made to simply create unneeded hierarchy. Your senior resident might know some operative details that are essential to understand how your patient is doing, and the resident might have a lower or higher threshold for ordering an abdominal CT based on intraoperative details or findings.
Always ask yourself how the CT will change your management. This second rule is a general one that you should apply every time you are ordering any test on your patient. No test, especially radiological, comes without a price. An unneeded abdominal CT results in unwarranted patient exposure to radiation, and cumulative radiation exposure is well known to increase the risk of malignancies in the long run. In the short term, a trip to the CT for patients with lines and tubes is a big burden for the nurses, and is not without its own risks: a chest tube might get dislodged, or the patient might be agitated thus requiring some conscious sedation, a further risk. So, always ask yourself “what will I find on the scan (or any test) that will change my current management?”
You answer your pager and hear: “Dr. Smith, radiology is on the line asking what kind of contrast you want for the CT scan you just ordered?” ...