CT limited by lack of iv contrast is found in radiology reports when there is a need to alert the referring doctor to the limitation of the study. IV contrast for CT is given through an IV in a vein. The contrast highlights certain structures that are seen on the CT.
Why is iv contrast given?
IV contrast allows many different abnormalities to be identified better then when IV contrast is not given. This includes injuries to organs, tumors, infections, and benign abnormalities. IV contrast also allows one to better say what an abnormality is when found on a CT.
Why isn’t iv contrast given to all patients?
IV contrast can not be given at all times. Some patients have severe allergies to contrast which prevents them from getting it. Patients that have kidney conditions which decreases their function below a certain point can not get IV contrast. Recently, there has been a shortage of IV contrast in the US because of supply chain issues.
Some patients with certain suspected conditions get a non contrast CT ordered. Some examples of these can be for kidney stones which are better seen without contrast. Bleeding in the head can be accurately diagnosed with a non contrast head CT.
What are some conditions that IV contrast helps for diagnosis?
IV contrast for CT allows us to identify more abnormalities following trauma. IV contrast let’s us see injuries to the abdominal organs like the liver and spleen. We may not see the bruising and tears to the organs on a non contrast CT.
IV contrast allows us to diagnose tumors with greater accuracy. IV contrast makes abnormalities in organs stand out much more. Tumors are much more easily seen when IV contrast is given. When we don’t give IV contrast, tumors may not be visible.
Infections are more easily diagnosed when you give contrast. Collections of pus or abscess is more easily seen when the iv contrast is given. This will look like a walled off collection often with gas inside. IV contrast makes the abscess stand out more in the normal organs and around them.
Sometimes we can make a diagnosis without IV contrast on CT. Bleeding, perforated bowel, kidney stones are some of the conditions that do not require iv contrast. Many conditions outlined above do. We may miss a diagnosis without IV contrast. Most conditions can be diagnosed with contrast however.
IV contrast is therefore important for making many diagnosis. It will allow the best test to be done for conditions like organ injuries, cancer, infections and benign abnormalities. IV contrast can not be given to all patients. We may therefore opt to do ta non contrast CT. Alternate tests like MRI and Ultrasound are some other possibilities.