You may have heard reference to something called an MRI with contrast. So what is an MRI with contrast? Is it different to a normal MRI?
Essentially, an MRI with contrast is a basic MRI which your radiographer will perform as usual. But the key difference is that beforehand, you will have had an injection that will improve the quality of the MRI image, so that your radiologist can better assess your health and diagnose any conditions you may have. So let’s find out a little more about what an MRI with contrast is.
Injections sound scary. Should I worry? Are there any risks?
There are few risks with injection. If you have normal kidney function, you should be able to get rid of at least 90% of the injection within a day. However, there are a couple of side effects that you should know about:
- You may experience some minimal headaches, nausea or slight dizziness shortly after the injection. These feelings pass quickly.
- In fewer than 1 in 1000 patients, you may have a mild allergic reaction to the shot. This manifests itself as an itchy skin rash around the injection site.
More severe reactions than this are extremely rare. 1 in 10,000 patients has a more severe allergic reactions, but this is easily dealt with using the same drugs as other allergic reactions. Because of these rare, but potentially serious side effects, every center like ours is equipped with a stock of medication that can be used in situations like these. This injection is still safer than the injection given for CT scans, too.
On even rarer occasions, the injection of gadolinium has caused Nephrogenic systemic fibrosis, or NSF. NSF causes patients to develop hardened skin and plaques, experience severe joint pain, and in some cases internal organ failure. But bear in mind that this reaction only affects those who have exceptionally severe pre-existing kidney conditions, and even in patients with conditions along those lines, it only affects fewer than one in a hundred. If you’re unsure, your radiologist may request a blood test before you have an MRI with contrast.
So if you’re honest with your doctor about your medical history, you have nothing to worry about!
When I have an MRI with contrast, what does the nurse inject me with?
When you have an MRI with contrast, you’ll be injected with what’s called gadolinium contrast medium. It sounds scarier than it really is! It contains gadolinium, which would normally be toxic. But manufacturers mix the gadolinium with a ‘chelating agent’. In simple terms, the chelating agent makes the gadolinium harmless, almost like watering it down. The radiologist injects the ‘dye’ into yout bloodstream, which then carries it around the entire body, from the head to the toes. This helps certain parts of your soft tissue to stand out better in the MRI, as we’ll talk about later.
There are also other agents that can be used, based on iron oxide, iron platinum, and manganese. Each one of these agents exists because we don’t yet have an optimal solution for producing contrast in MRIs, and because a number of different brand names want to dominate the market with their product! Your radiologist may also not need to give you an injection, because some of these agents can be taken orally. This is especially the case if you need your gastrointestinal tract scanned.
If I have a phobia of needles, do I still have to have an MRI with contrast?
You don’t have to have the injection if you really don’t want to. Only about one in three MRI scans actually use this method. That’s because it either isn’t necessary, or the patient is deathly afraid of needles! Your radiologist will still be able to see and diagnose your condition, but they may require more extensive scanning than usual, to make up for the fact of reduced clarity.
Before you have your MRI, your radiologist will consider whether the injection will actually be helpful. They will also ask you whether there are currently any reasons why you might not want the injection, like being pregnant, or whether you’ve previously had a serious allergic reaction to something else. These factors might mean that the needle wouldn’t be the best option for you.
If your radiologist absolutely insists that you need the injection, but you absolutely insist that you would rather not have it, you may need to be referred to somebody else!
Is an MRI with contrast better than one without contrast?
An MRI with contrast helps certain things stand out when scanned. So, for instance, the ‘dye’ doesn’t highlight bone because blood doesn’t flow through the bone! But the brain, for instance, needs a lot of blood- so the gadolinium will highlight different areas of the brain. The same goes for the organs, which all stand out against the dark black background of an MRI scan. This is helpful for your radiologist, because they’ll be better able to see inside your body, and diagnose any condition you may have.
In particular, an MRI with contrast can help your radiologist to pinpoint conditions like inflammation and disease in the soft tissue of the body and brain. This results in more efficient diagnosis of your condition. It can also mean that your radiologist can more accurately describe the stage of conditions like cancer. That being said, an MRI without contrast is still a perfectly acceptable way for your radiologist to diagnose your condition. Radiologists still use them in the majority of MRI scans.