PMC5964500_01
Follow-up ultrasound at 16 weeks and 6 days of gestation reveals a vascular malformation (arrow) at the lower uterine segment with swirling flow within the malformation consistent with a pseudoaneurysm.
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A large uterine cavity pseudoaneurysm measuring 4.2 x 3.8 x 3.7 cm and appearing to arise from abnormal placentation at the previous cesarean scar was identified (Figure 1).
Coronal T2-weighted image of the pelvis at 18 weeks of gestation demonstrates a hypointense round structure (arrow) at the lower uterine segment infringing upon (and invaginating into) the gestational cavity. Fetal knee abuts and deforms the lesion.
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MRI one week later confirmed a 4 cm hypointense lesion projecting into the lower right uterine cavity at the inferior margin of the placenta (Figures 2 and 3). Management options were discussed to include conservative imaging observation versus embolization.
Maternal coronal (sagittal fetal) T2-weighted image of the pelvis (a) at 18 weeks of gestation with similar fetal positioning in relation to the lesion on ultrasound (b) as if the fetus (arrow) is sitting (or bouncing) on the lesion (arrowhead). Note the Yin/Yang swirling flow on color Doppler.
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MRI one week later confirmed a 4 cm hypointense lesion projecting into the lower right uterine cavity at the inferior margin of the placenta (Figures 2 and 3). Management options were discussed to include conservative imaging observation versus embolization.
Coronal T1 MRA and 3D surface rendered reconstruction (Vital Images  postprocessing software) of the aberrant right ovarian artery branch feeder at 19 weeks of gestation. The proximal right ovarian artery originates from the aorta and courses into a tangle of vessels (long arrows) in the right abdomen ((a) and (c)) before penetrating the myometrium (curved arrows) ((b) and (c)) and extending caudally (short arrows) as an arcuate artery to the lesion. Pseudoaneurysm (arrowhead), uterine cavity (chevron), and aortoiliac vessels. Draining vein (blue).
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MRA revealed two suspected feeding vessels: a branch off the right ovarian artery parasitized to the uterine arcuate artery (Figure 4) and a branch off the right uterine artery parasitized to the uterine arcuate and radial arteries (Figure 5).
(a) Sagittal oblique reconstruction of T1 MRA and 3D surface rendered image (Vital Images postprocessing software) (b) of uterine artery feeder (arrows) to the pseudoaneurysm (arrowheads). Uterine cavity (chevrons).
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MRA revealed two suspected feeding vessels: a branch off the right ovarian artery parasitized to the uterine arcuate artery (Figure 4) and a branch off the right uterine artery parasitized to the uterine arcuate and radial arteries (Figure 5).
Interventional fluoroscopic images. (a) Tortuous right ovarian artery off the aorta (long arrow) with perforating branch into the myometrium (short arrow). Faint blush of pseudoaneurysm on real-time imaging (not shown). (b) Selected right hypogastric artery showing uterine branch (arrowhead) leading to faint oval blush of pseudoaneurysm (chevron). (c) Subselected uterine artery feeder (arrowhead) and pseudoaneurysm blush (chevron). (d) Postcoiling images of parasitized right ovarian and uterine arteries without flow to the target lesion.
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A right ovarian arteriogram revealed a prominent tortuous right ovarian artery similar to that seen on MRA (Figure 6). The right ovarian artery was then embolized with coils (Figure 6). A right hypogastric arteriogram revealed a prominent right uterine artery and a large ovoid lesion opacifying with contrast consistent with the target lesion (Figure 6). Postcoil imaging revealed no lesion opacification (Figure 6).
Postprocedure ultrasound the next morning demonstrates significantly reduced flow within the pseudoaneurysm (arrow).
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Ultrasound interrogation the next morning revealed no flow within the lesion (Figure 7).
Transverse (a) and longitudinal (b) ultrasound two days after procedure reveal return of flow to the lesion, however, with significant reduction in lesion size to 3.3 cm (arrows) form 5 cm before embolization.
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Repeat ultrasound 24 hours later, however, showed recurrence of small blood flow into the lesion, with a significant decrease in lesion size to 3.3 cm, which remained stable prior to discharge 4 days later (Figure 8).
Final ultrasound image taken prior to delivery demonstrates persistence of the aneurysm, although it was significantly reduced in size to 2.0 cm (arrow).
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The pseudoaneurysm progressively decreased in size, measuring 1.4 x 2.0 cm just prior to delivery (Figure 9).