01.04 CT & MR Angiography

CT and MR angiography are used to diagnose disease in the vessels of the body like in this MRA here. CT is computed tomography, and MR is magnetic resonance. These two tests both use a type of contrast and are similar in results, but use different mechanisms to produce the pictures. Let’s explore the difference.

So the CT angiography uses radiation to bounce off of tissues and create cross-sectional images for a 3D view of the inside of the body. The type of contrast used is iodinated. Here’s a picture of a CTA showing a huge abdominal aortic aneurysm.

MR angiography uses a magnetic field to realign hydrogen atoms in the body, and radio waves to cause them to make signals used to create the pictures. MR is high resolution and uses a gadolinium contrast. Guys, look how cool this picture is and how clearly you can see the vessels in the brain. Next let’s discuss what to do to prepare the patient for these procedures. 

So before the procedure, check and make sure the BUN and creatinine lab draws have been done to view the kidney function. If they aren’t, the radiology tech will ask you to have the doctor order them before using contrast that may harm damaged kidneys. Ask the patient if they are allergic to contrast, and if they are find out what test they had previously as the contrast type is different for the CT and MR. If they are having the MR angiography, fill out that MRI form asking the patient about metal exposure and have them sign it. Fax it down to radiology so they can look it over for any issues before the test. There should be an area for contrast consent on that form as well. If the patient is having a CT angiography, have the patient sign a CT contrast consent after explaining the procedure. Disconnect any IV lines before the test because the tech will be using the IV for contrast administration. 

During the procedure, position the patient on the board. Ask the patient to stay still for clear images. If an MR is being performed, remove all metal from the patient and the room. 

After the procedure is over, check the IV patency with a saline flush and then reconnect the lines if they have IV fluids ordered. Hold the metformin for 48 hours if they take this drug for diabetes  to protect kidney function. Now let’s talk about patient education. 

Explain to your patient the importance of staying still during the procedure for a clear picture. Let them know that the tech will provide breathing instructions during the test. It’s helpful to tell them that the radiologist will interpret the picture and the doctor will explain the results to them. Tell them they can start taking their metformin again 48 hours after the test. 

The priority nursing concepts for the patient with a CT & MR angiography are patient education, patient-centered care, and safety.