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Here's our overview.

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I'll be talking about the rationale for breast MRI.

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Why do we use this test to detect breast cancer.

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Clinical indications for the exam.

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Breast anatomy.

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Positioning and protocol.

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MRI BI-RADS.

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BI-RADS assessment categories.

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Basic interpretation.

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Reporting.

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And then we'll go through cases.

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So the rationale for breast MRI,

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it's important when we're thinking about breast cancer detection in general,

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that we think about the goals of breast cancer screening and detection.

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What we're really trying to do is obtain

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early detection of small node negative cancers.

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We want to reduce the rate of interval

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cancers and reduce morbidity and mortality from breast cancer.

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We know that tumor size is related

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to mortality, and the mammography randomized control

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trials, showed decreased mortality from breast cancer.

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But we also know that mammography is

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limited by tissue density and overlapping tissue.

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So why do we use breast MRI?

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Well, it's not limited by breast tissue density.

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There's no ionizing radiation.

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It's a vascular base screening.

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So in addition to providing anatomic

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details, there's also some functional information based on that vascularity.

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It's the most sensitive exam we have for breast cancer detection.

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We know that it detects small,

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node negative, invasive cancers, and that there's a low interval cancer

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rate for people who are screened regularly.

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MRI preferentially detects higher grade

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lesions, and there's an implied decrease in morbidity and mortality.

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Back in the late 1990s and early 2000s, there were several trials looking

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at breast MRI compared to mammography and ultrasound.

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And this table shows a number of those trials.

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And you can see the last three lines

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in the table are the sensitivity of MRI, sensitivity of mammography,

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and sensitivity of ultrasound in these various trials.

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And you can see that the sensitivity of MRI is very high. If you look across

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this line, ranging anywhere from the high 70% to 100% sensitivity.

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So we know from all of these trials

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that MRI is very sensitive for detection of breast cancer.

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Janice Sung at Memorial Sloan Kettering

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published an interesting study in 2016, demonstrating that MRI also detects

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significant breast cancers compared to mammography.

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And in this study, the group reviewed over 7500 high risk women who underwent both

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mammography and MRI over a six year period.

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This is a large study.

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So they had over 18,000 MRIs and over 26,000 mammograms.

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They detected 222 cancers.

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75% of them were found on MRI, and 19% were found on mammography.

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And there were only a handful of interval cancers.

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And what was interesting was that MRI

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detected more invasive cancers, especially those small node negative ones,

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and mammography detected more DCIS and less invasive cancers.

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We know from multiple trials that MRI has

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a high cancer detection rate, usually on the order of about 15 per thousand.

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And that compares to mammography or

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mammography plus ultrasound, which is in the seven to nine per thousand range.

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We know that MR detects these small node negative invasive cancers that we're

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trying to detect, and that there's a low interval cancer rate.

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And based on the Sung study and other

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studies, we know that MRI detects more biologically significant tumors.

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And again, we have that implied decrease

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in morbidity and mortality from early detection.

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There are some disadvantages of MRI.

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One is the cost.

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This is an expensive exam.

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It also, if you do all of the recommended sequences, it's a fairly long exam.

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It's an uncomfortable position.

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The patient is positioned prone with their

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face and a face holder and their upper body supported, largely leaning on their

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sternum, which is not terribly comfortable position.

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It requires placement of an IV and administration of contrast.

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Many of our patients are claustrophobic

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and just can't tolerate being in the MRI scanner.

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There's also a risk of contrast allergy

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and then the exam itself has relatively low specificity.