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Now we're gonna talk about mammographic architectural distortion and how

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DBT can help us identify distortions on MRB. Architectural distortion is

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defined BI RADS as distorted appearing parenchyma with no

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definite mass visualized. This includes thin straight lines or spiculations

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radiating from a point. It can be focal retraction, distortion or straightening

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at the anterior posterior edge of the parenchyma, but it also may be

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considered an associated feature within BI RADS, with asymmetries, masses

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or calcifications. In this case demonstrated here, we have a spot at MLO

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production, and you can see here there's some distortion

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in the upper breast with some radiating lines coming out from this sort

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of central point. This was later a subsequent biopsy there's a large invasive

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ductal carcinoma calcification. Common pathologic entities associated with

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architectural distortion of course include malignancies, particularly invasive

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ductal or lobular cancers. An architectural distortion tends to be a marker

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of more slow growing malignancies. That's related to that desmoplastic response,

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which causes the distortion to appear. You can also see high risk lesions,

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such as radial scar or complex sclerosing lesions with atypia. In addition,

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we can also see benign findings. So post procedural scarring from excisional

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biopsy, opectomy or reduction surgery, also fat necrosis or sclerosing adenosis

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or fibrosis. These can all lead to a distorted appearance. And in some

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ways, at least, particularly for the benign findings,

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the clinical history is also really important to evaluate when you're looking

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at these exams, either given to you by a technologist or if you're

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doing a diagnostic exam when you're talking to the patient.

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On imaging, architectural distortion can be difficult to detect in some

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areas of dense tissue. Conventional 2D imaging, this may be a significant

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source of mismalignancies. Of course, if it's a very large area of distortion,

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it's not hard to miss at all, but distortions are more readily identified

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with tomosynthesis. And approximately 73% of identified distortions are

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seen at tomosynthesis only. So not on the SM view and not on

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the associated 2D view if you're acquiring that separately. Tomosynthesis

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may also more readily be identified with an associated mass, which may erase

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suspicion for an underlying malignancy. Importantly, there are no definite

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imaging features which reliably distinguish between benign and malignant

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distortion. So basically any distortion that you see needs to be worked

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out and further evaluated or at least determine what might be causing it.

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If you can prove that a patient has had a prior surgery in the

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location where you're looking at a distortion, either by using a scar marker

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or some clinical history, then that can really help you to put that

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into a benign category. But without that definite history, you're pretty

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much stuck doing some kind of further evaluation, and usually that's gonna

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lead to a biopsy if the distortion is indeed real. Tomosynthesis may also

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aid in the localization of architectural distortions that are initially

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only visualized on one view. This does happen. Of course, we have to

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use the scroll bar to help us do that, and we know that

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there's certain aspects of the scroll bar we need to be careful with

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in terms of lesion localization. Tomosynthesis can also help us by identifying

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adjacent anatomic landmarks. That's either like sort of an area of focal

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fiber tissue, for example, or maybe a distinct course calcication that's

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nearby. You can use that to help you determine where in the tomosynthesis

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stack you're gonna find your area of distortion if it's all. So in

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this case, we have CC and MLO spot compression views on either sides of

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the screen and in the center, a full field MLO. Now,

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you might see there's some maybe potentially distortion down here in this

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full field MLO view. It's very difficult actually to see in these SM

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views. In fact, I probably wouldn't say you see very much at all other

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than some heterogeneous semen tissue. But as we scroll through the tomosynthesis,

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you can get the sense that there's maybe something more here with some

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radiating lines coming out from a central point and also up here on

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this full field MLO view. But on this MLO spot compression view,

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we can really see this a lot better with some radiating lines here,

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potentially an associated mass located centrally here. In terms of management,

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as I mentioned correlation with clinical history is really critical

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to rule out benign causes. You can ask the patient, search for prior history

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or documentation. You need to complete the diagnostic exam with spot compression

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views. Focus compression may improve visualization of the distortions. However,

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we have seen some cases too where spot compression actually causes subtle

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distortions to resolve entirely. So sometimes repeating the full field

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view can be helpful, or if you have a high index of suspicion,

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based on just on the screening exam, it's important to go ahead and

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do the diagnostic ultrasound where you think the lesion might be.

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Because I have had at least a couple of cases where we see

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it really well on the screening exam, but the patient presents for diagnostic

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imaging, doesn't look very exciting at all. We end up going to ultrasound

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and find a malignancy right where we expected to be, based on the

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screening exam. So diagnostic ultrasound is recommended for all suspicious

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distortions. If you find a sonographic finding is present, then of course

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ultrasound guided biopsy is the way to go. If there is no sonographic finding

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and you're still worried about the distortion, based on the mammographic

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views, then of course stereotactic biopsy is recommended and we have the

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benefit of having DVT or tomosynthesis guided stereotactic biopsies to make

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that sort of biopsy even easier to do.