Interactive Transcript
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The next thing that we look for is background parenchymal enhancement.
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And that can be described as minimal, mild, moderate, or marked.
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And again, that's kind of a spectrum. A little bit subjective.
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And then the background can be described as either symmetric or asymmetric.
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And we assess this on the first post contrast subtraction series.
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This is an example of a patient with minimal background parenchymal enhancement.
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So you can see, since this is a subtracted image,
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only the enhancing parts are going to be really well visualized.
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So you can see blood vessels,
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those are going to be bright, but there's really not very much happening
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here in the breast tissue, as far as enhancement.
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And then, this would be an example of mild background parenchymal enhancement.
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There's a little bit more high signal intensity within that breast tissue.
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Next would be moderate background parenchymal enhancement.
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Here's a patient with a busier breast tissue.
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There's some...
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She has some cysts and some areas of non-mass enhancement,
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but this background is more moderate So, basically, more enhancement.
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And then here's an example of a patient with marked background parenchymal enhancement.
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This happens to be a patient who's
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currently breastfeeding and that can certainly increase that background
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parenchymal enhancement.
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We often will see marked background parenchymal enhancement,
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abbreviated as BPE, in a patient who is breastfeeding.
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So marked BPE.
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And this is an example of asymmetric BPE.
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All of the other examples we looked at
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were fairly symmetric from side to side, but this patient is asymmetric.
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And in this case,
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the right side has marked background parenchymal enhancement and the left side, really,
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doesn't have much enhancement at all.
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And the reason for this was that the patient have had a lumpectomy
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on the left side in the past, and have had a whole breast radiation to the left breast,
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which is one of the things that can reduce background parenchymal enhancement.
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So, it's important to think about factors
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that are affecting background parenchymal enhancement, and that can include the phase
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of the menstrual cycle, adding hormones, like hormone replacement
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therapy, some form of oral or patch type
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contraceptives, an IUD that emits hormones, and some supplements.
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Some of our patients are on hormonal
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suppression, either for breast cancer treatment or chemo prevention.
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And when that stops, they can have a rebound where their
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background parenchymal enhancement increases after stopping therapy.
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And then breastfeeding,
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which makes the breast very proliferative, can increase BPE as well.
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Anti-hormonal therapies such as Tamoxifen and Aromatase Inhibitors
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can decrease background parenchymal enhancement, often quite significantly.
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And then, as a patient naturally goes through menopause, that will decrease BPE.
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And like we mentioned before,
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radiation therapy, which is often unilateral, will decrease BPE.
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So moving on to a case. This is a 33-year-old woman who's
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currently breastfeeding and has a recent diagnosis of left breast cancer.
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Okay, so in this case, I'm showing the T1-weighted non fat-saturated image
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on the left side and the subtracted image on the right side.
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And just wanted to show you that you can have extreme fibroglandular tissue and
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marked background parenchymal enhancement, which this patient does have.
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Just going through
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this case, you can kind of see that, that she enhances quite a bit.
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And this was a breastfeeding patient.
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And in other cases,
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there can be a mismatch where the amount of fibroglandular tissue does not
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really match the amount of background parenchymal enhancement.
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And we'll look at that next.
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So our next case is a 57-year-old woman for high risk screening breast MRI.
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In this patient, we can see that there is, again, extreme fibroglandular tissue,
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and the background parenchymal enhancement is actually pretty mild.
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And as we scroll through this, we can see that
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other than blood vessels and a little bit of background, there's not very much.
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So we can really see here that you can
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have a lot of fibroglandular tissue that really doesn't enhance with MRI.
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So this can help us in patients who have
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a lot of breast tissue density on their mammogram.
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They may have a difficult ultrasound as well, but screening them with breast MRI
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may be very helpful because their background is pretty quiet,
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and if something new appears, we should be able to see it with MRI.
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