CT Scan or MRI - what do I need?

Our patients are often asked to get a CT Scan or an MRI. We know it can be confusing. Here are some straightforward things to know about these tests.

First, both scans generally require patients to lie on a movable table that passes through a big, donut-shaped machine.

A CT scan is like a series of X-rays taken rapidly (n a circle around you). When combined and looked at together, they provide a detailed, 3D image of your body.

MRIs utilize a large, powerful magnet and radio waves to create a similar image. The radio waves cause the molecules in your body to line up in a certain way, and they send out signals when they revert to their normal positions. This gives us information about the different types of tissue in your body. This is a very important distinction.

So, the natural question is which scan to use?

Like most things in medicine, that depends on the patient, their particular type of cancer and what question we are trying to answer. And as we all know - everyone’s case is unique.

If we want to assess a bony structure, for instance, then a CT scan would be ordered. But if we are trying to distinguish between normal tissue and cancerous tissue, an MRI is the route to go. If someone has fluid built up it can distort an MRI and make it difficult to get a good, clear image.

Therefore, whereas we know which scan is better for which situation it also depends on what’s the best picture we can get based on the patient’s condition.

We hope the above helps to get a better understanding of the different imaging ordered.