What is the difference between a computed tomography (CT) and magnetic resonance imaging (MRI) in working up uterine cancer?
A CT scan uses x-rays to build a picture. To make contrasts between blood vessels, lymph nodes, and normal, typically an iodine-based dye is used (to help light up vessels) and barium contrast is drunk (to help outline the stomach, small intestines, and colon).
In these ways, CT scans can distinguish between flesh, bone, and blood vessels. It is a good way to evaluate a tumor’s size and whether or not there is evidence of spread, and it is frequently used to stage endometrial cancer.
MRI stands for magnetic resonance imaging. MRI uses radio waves traveling through a magnetic field. By using contrast agents, it can significantly make out what is being imaged (that is, what is normal versus abnormal and how they relate to each other).
In women with endometrial cancer, it is a great test to determine if a uterine cancer is superficial (meaning, it is arising within the endometrium) or deeply invasive (meaning it is so big it involves the deeper muscular layers of the uterus or even involves structures outside of the uterus). MRIs cannot be done if patients are too obese, have metal in their body, or are claustrophobic as it requires one to sit or lie down in a container that is required to be closed.