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This is an MRI of the abdomen and

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pelvis in a patient referred at

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19 weeks' gestation from the Maternal Fetal

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Medicine Clinic after abnormal ultrasound.

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The notes that were sent by the referring

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clinician specifically indicated that

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they were having trouble visualizing

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the cervix on the patient's ultrasound.

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Here we have sagittal T2-weighted

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images of the abdomen and pelvis.

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Again, our steady-state free precession

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images are on the left, and our

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turbospin echo images are on the right.

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As we scroll through the images, we can

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see almost immediately why the providers

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in clinic were having difficulty evaluating

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the cervix, which is elongated and

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anteriorly displaced for this patient.

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So all of this T2 brightness is a small

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amount of fluid within the cervical

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canal, and this is the anterior lip

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and posterior lip of the cervix.

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Up here is the internal cervical

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os, and we can see abutment of the

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os by the edge of the placenta.

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So this patient has a marginal placenta previa.

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When we evaluate the uterus, it's in an odd

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configuration, certainly different from what

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we've seen previously with pregnant patients.

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We can trace our T2 heterogeneous myometrium

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all the way around the uterus for this patient,

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and we can note that there is bulging of the

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low anterior uterine segment of the placenta,

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and displacement of the fundus, which is located

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in the presacral space within the pelvis.

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We see similar findings on the

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steady-state free precession images.

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I'd also like to point out that this

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patient has had a kidney transplant, which

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we can see in the right lower quadrant.

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Let's look at the axial images for this patient.

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Again, steady-state free precession images on

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the left, turbo spin echo images on the right.

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We see the kidney transplant

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in the right iliac fossa.

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Here's the gravid uterus.

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And, again, we can see that the fundus of

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the uterus is within the presacral space.

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The placenta is visualized here.

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It's minimally heterogeneous, and so even

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though we are seeing the placenta inferior

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and deep in the pelvis on these images,

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it is technically a fundal placenta.

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Returning to the sagittal images, we can once

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again evaluate the orientation of the uterus.

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And so if we're discussing or describing

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version and flexion, this patient is markedly

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anteverted in terms of the orientation of

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the cervix and markedly retroflexed with the

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uterine fundus located in the presacral space.

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This patient is presenting in the

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second trimester of pregnancy.

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We can see that the fetus is fairly

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developed, and because of the size of the

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uterus and its orientation, a diagnosis

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of uterine incarceration was made.

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Uterine incarceration is a term

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that describes entrapment of a

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retroverted uterus in the pelvis.

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It's fairly rare, estimated to

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occur in 1 in 3,000 pregnancies.

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Patients often present early in the second

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trimester, and on exam, these patients will have

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a fundal height that's discordant with dates.

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On ultrasound, they may also see anterior

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location or displacement of the cervix.

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There are multiple potential methods

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of reduction, some of which are manual

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and can be done in the office or in the

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operating room with or without anesthesia.

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It's important to attempt reduction

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for these patients as complications

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can include uterine or bladder rupture.

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For the case that we previously described,

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the patient presented to the clinic one month

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later with acute onset abdominal pain.

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When we did follow-up MRI for her, we saw

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that the uterus had corrected itself and

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had moved from the presacral space into

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the expected location in the abdomen.