From the Guidelines
The main difference between a CT abdomen with contrast and without contrast is that contrast-enhanced scans are generally better for detecting vascular issues, tumors, infections, and inflammatory conditions, while non-contrast scans are preferred for evaluating kidney stones, calcifications, and in patients with contraindications to contrast media. When considering the use of CT abdomen with or without contrast, it's essential to weigh the benefits and limitations of each approach.
- Contrast-enhanced CT scans use an intravenous contrast agent to highlight blood vessels, organs, and abnormalities, making them more visible and allowing for better characterization of subtle bowel wall abnormalities and complications of conditions like diverticulitis 1.
- Non-contrast CT scans, on the other hand, do not use this agent and are preferred for evaluating kidney stones, calcifications, and in patients who have contraindications to contrast media such as allergies or impaired kidney function. Some studies suggest that the addition of IV contrast significantly improves the conspicuity of findings such as interrupted mucosal enhancement and bowel wall hyperenhancement, making the CT examination more sensitive in diagnosis 1. However, other studies indicate that there is limited value in performing a CT abdomen and pelvis without and with IV contrast for certain indications, such as gastric disease 1. In general, the choice between a CT abdomen with contrast and without contrast depends on the specific clinical question being investigated and the patient's medical history, and contrast-enhanced CT scans are usually the preferred initial choice, unless there are contraindications to contrast media 1.