Neurovascular Imaging: MRA, CTA, and TCD (Nursing)

by Prof. Lawes

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    00:00 An MRA is a magnetic resonance angiogram.

    00:05 So it's a type of magnetic resonance imaging or MRI.

    00:08 Okay, so let's talk about what an MRA is.

    00:12 Now, notice, there's a different vowel at the end of that, that's because an MRA can be done with the same machine as an MRI.

    00:19 It uses a magnetic field and pulses of radio wave energy to provide pictures of the blood vessels inside the body.

    00:26 So your patient is going to go to the same place for an MRA, but it's a little bit different than an MRI.

    00:33 Now we're going to get some great pictures to look at that blood supply.

    00:37 So an MRA of the head is done to look at the blood vessels leading to the brain.

    00:41 Now what they're going to be looking for is they look for a bulge, that could be an aneurysm.

    00:45 they'll look for a clot or even a narrowing because from stenosis, because of plaque.

    00:50 So, essentially, it's the same kind of concept.

    00:53 When we're checking out the blood supply for the heart, we're looking for similar things.

    00:57 We also want a good blood supply to the brain.

    01:00 That's why the MRA can show us about clots, aneurysm, stenotic areas, because of plaque.

    01:07 So, the patient will lie on the table and the table moves into the MRI machine.

    01:13 Now, remember, we're doing an MRA, but it's in the same MRI machine.

    01:18 The test usually is completed in about 30 to 60 minutes.

    01:21 Now here's a side note, your patient may not know they're claustrophobic until they get inside the tube.

    01:28 So, that's a question you definitely want to ask your patient before they go down for a test: an MRA or an MRI.

    01:34 Because sometimes this can be really traumatic for the patient and you may need to request the healthcare provider to probably order something, it could help the patient relax a little bit.

    01:43 The problem is going to be if it's a neurological test we're not gonna want to sedate them because we want to keep an eye on any neural symptoms.

    01:51 So, it may be something you have to help your patient work through without the use of any medications.

    01:57 A CTA is a CAT scan angiogram.

    02:01 So it's computed tomography, that's what CT stands for, and we just say CAT, but a CTA is a computed tomography angiogram So this test uses X-rays and it gives us a really detailed picture of the heart and the blood vessels.

    02:15 So we can look at the blood vessels that go to the heart, the lung, brain, kidneys, head, neck, legs, and arms.

    02:22 Yeah. So we listed everything out.

    02:25 What will show you, it'll just tell us detailed pictures of the blood supply just about everywhere.

    02:30 The test is non-invasive, so that's super cool, but it does involve dye, and that's what I want to talk to you about.

    02:38 When we say dye, it's called contrast media.

    02:40 Now the patient will receive it in their IV, so the vessels are easier to scan.

    02:45 So that's a good thing.

    02:46 But some people have some real problems with the dye.

    02:49 Now if you've ever had this dye in, sometimes it makes you feel really warm.

    02:53 So usually the person who's administering the test or the dye will let the patient know, "This might make you feel a little weird at first," but as long as the patient expects it, they're usually okay.

    03:04 But if the patient is taking a medication called metformin, now this is a very commonly prescribed medication, oral medication, that controls blood sugar.

    03:15 So type 2 diabetics take metformin.

    03:18 Women with PCOS, polycystic ovarian syndrome, take metformin.

    03:23 So it's meant to control their blood sugar.

    03:26 The problem is metformin cannot be in the system when someone receives this type of dye or it could be really lethal to their kidneys.

    03:35 So you always want to ask a patient before they receive dye if they're taking metformin, specifically.

    03:41 So you ask them if they're taking that medication.

    03:43 If they are, you need to postpone the test for a couple days because you want to have one- to two-day window in between the last time they took the metformin and the test.

    03:53 And then, after the test, you want another one- to two-day window depending on the patient before they start taking metformin again.

    04:01 So they're going to have to work with the healthcare provider to decide how he can best provide glucose, blood glucose control during that time when it's not best for that patient's kidneys to receive their metformin.

    04:13 Also, any renal patient, anybody whose kidneys are struggling, if they're getting dye, we need to monitor them very closely.

    04:21 We want to make sure you do kidney labs before you take them down for the test when they receive the dye to see what the status of their kidneys are.

    04:27 You want to make sure they get lots of fluids, maybe IV fluids and oral fluids, and you want to watch their renal numbers after the exam.

    04:35 A transcranial Doppler is another non-invasive test.

    04:39 Whoo-hoo! Patients don't mind this because they don't hurt.

    04:43 It's painless and it's a neural vascular ultrasound that uses high-frequency sound waves.

    04:49 So think about when a woman has an ultrasound, you can do an ultrasound of the heart, ultrasound of a baby.

    04:54 This is a transcranial Doppler.

    04:57 So, it measures the rate in the direction of blood flow inside the arteries of the circle of Willis Look at this graphic. I think this is pretty cool.

    05:06 You can see you've got a graphic of the transcranial Doppler right there on the skull and you see inside the skull-- Now you and I both know there's more in your head than that.

    05:15 But we've highlighted the circle of Willis in red just to remind you about that critically important blood supply in your brain.

    05:23 Now transducers are placed on the patient's skin at the temples, and at the base of the skull, at the back of the neck, or on the closed eyelids.

    05:32 Now TCD can be done and helped diagnose a TIA, a stroke which we also call a CVA, a cerebrovascular accident, or a subarachnoid hemorrhage.

    05:43 Okay, so we're talking about a lot of tests here.

    05:47 Why does this matter? Because these are widely used tests.

    05:51 As a nurse, you need to anticipate what type of testing might be done for your patient.

    05:55 You need to understand what the test is like as you can help prepare your patient.

    05:59 You need to know which tests are done and what they can rule out.

    About the Lecture

    The lecture Neurovascular Imaging: MRA, CTA, and TCD (Nursing) by Prof. Lawes is from the course Stroke (Nursing). It contains the following chapters:

    • MRA, CTA and TCD
    • CTA
    • TCD

    Included Quiz Questions

    1. Stenosis
    2. Aneurysm
    3. Clot
    4. Hemorrhage
    5. Hematoma
    1. The combination of both metformin and contrast dye can cause kidney failure.
    2. Metformin interacts with the contrast dye and can cause anaphylactic shock.
    3. The dose of contrast dye should be reduced since metformin is a form of contrast dye.
    4. This scan is contraindicated in a client who has taken metformin.
    1. Transient ischemic attack (TIA)
    2. Cerebrovascular accident (CVA)
    3. Subarachnoid hemorrhage (SAH)
    4. Seizures
    5. Migraines

    Author of lecture Neurovascular Imaging: MRA, CTA, and TCD (Nursing)

     Prof. Lawes

    Prof. Lawes

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