Interactive Transcript
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This is an MRI of the abdomen and pelvis in
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a patient presenting at 28 weeks gestation
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referred from the maternal-fetal medicine
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clinic after abnormal obstetric ultrasound
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with concern for placenta accreta spectrum.
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Again, we've placed our steady-state free
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precession images on the left and our
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turbo spin echo images on the right.
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As we scroll inferiorly, we begin to
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see the gravid uterus come into view.
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We can see T2 heterogeneous myometrium
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in its entirety surrounding the gestational sac.
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As we scroll inferiorly, the
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placenta begins to come into view.
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We can see direct abutment of the myometrium
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by the placenta here with a relatively normal
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overlying appearance of the myometrium.
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As we scroll more inferiorly, we can see that
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the bulk of the placenta is low-lying and is
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along the left lateral aspect of the uterus.
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We also begin to see classic features
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of placenta accreta spectrum.
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Large placental bands and engorged abnormal
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vasculature within the placenta at this level.
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When we try to follow the myometrium
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overlying the placenta, we can see
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that it's relatively easy to identify
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the muscular layer more superiorly.
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But as we scroll inferiorly, we begin to lose
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the uterine myometrium overlying the placenta.
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And as we near the level of the cervix and
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upper vagina, there's a mass of placental
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tissue with little to no intervening myometrium.
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Particularly inferiorly within the pelvis, as we
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have this mass of placental tissue in the region
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of the upper vagina, I'd like to point out the
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number of asymmetric and engorged blood vessels
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in the left hemipelvis that are
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extending toward the placental mass.
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We'll revisit this in a moment.
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These are coronal T2-weighted
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images of the same patient.
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Again, we can see a low-lying,
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left-sided placenta with features
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of placenta accreta spectrum.
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The placenta has an abnormal, rounded contour.
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It's thickened in multiple
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locations without smooth tapering.
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We see large aberrant placental vessels,
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placental heterogeneity, and placental bands.
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In addition to marked thinning and
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absence of the myometrium inferiorly.
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Again, within the left hemipelvis, we can
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see multiple dilated blood vessels, which
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course toward the cervix and upper vagina.
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These are the sagittal T2-weighted images
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of the abdomen and pelvis for this patient.
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We can see that like many of the patients
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with placenta accreta spectrum, this patient
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also has complete placenta previa, with the
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placenta covering the internal os of the cervix.
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The placental bands
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and aberrant placental vessels are evident
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on the turbo spin echo sequences for this
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patient and are much more apparent than they
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are on the steady state precession images.
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An important distinguishing feature when
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you're trying to determine if something
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is a placental band rather than a vessel,
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is if it's dark on both sequences, you
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can confirm that it's a placental band
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rather than an engorged blood vessel.
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If it's dark on the turbo spin
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echo sequences only, you can favor
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an engorged placental vessel.
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Now, let's revisit the axial
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images for this patient.
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I'd like to again focus on the
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blood vessels that seem to
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be recruited in the pelvis here.
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As we mentioned in the region of the cervix
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and upper vagina, this patient has a focal
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placental mass without intervening myometrium
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and extensive engorgement of the left greater
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than right pelvic sidewall vasculature.
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When we reported this case, we raised suspicion
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for placenta percreta, but in addition to
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this, we also said that there was likely
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recruitment of the cervical vaginal plexus,
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particularly on the left, and that further
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evaluation with angiography was warranted.
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