Conjoined twins - cephalo-thoraco-omphalopagus

Case contributed by Dr Ammar Haouimi


G3P2 at 23 weeks of rural origin. The ultrasound of the 1st trimester done by general practitioner revealed a twin pregnancy according to the ultrasound report.

Patient Data

Age: 30 years
Gender: Female

Monochorionic monoamniotic (MCMA) twin pregnancy at 22 weeks+ 5 days, bicephalic position.

The fetuses are joined at the cephalic poles (cephalopagus), thorax (thoracopagus), and abdomen/pelvis (omphalopagus).

  • cephalic pole: there is no connection between the cerebellar or cerebral parenchyma, but have nonseparable skin contours.
  • spine: at the cervical region it is difficult to say that both fetuses have the same or separate cervical spine. beyond this point, the spine of both fetuses is separated well-visualized on the video images.
  • chest: there are a single heart and a single pair of lungs.
  • abdomen/pelvis: apparently both fetuses have separated digestive tract (stomach, small and large bowels), urogenital tract (kidneysurinary bladder, and uterus), and a single liver.
  • upper/lower limbs: separated upper and lower limbs (each fetus have four limbs).
  • placenta/umbilical cords: single placenta, of posterior fundal insertion grade 2 with separated umbilical cords.
  • amniotic fluid: normal amount with no dividing membrane.
  • sex: both females

This fetal MRI was performed 11 weeks later (at 34 weeks of gestation).

The MRI sequences show more anatomical details, especially regarding the central and peripheral nervous systems, which were not well-visualized especially at the cervical region.

Case Discussion

A case of conjoined twins (cephalo-thoraco-omphalopagus). The patient had a cesarian section 12 days after the MRI exam, unfortunately, the twins died immediately after.

Ultrasound remains the mainstay of fetal imaging, however, the combination of ultrasound and MRI is superior to ultrasound alone, especially in complex pregnancies such as twin pregnancies and conjoined twins.

MRI is superior to the ultrasound regarding the anatomical details which are useful for preoperative assessment of complex pregnancies as well as difficult cases such as maternal obesity and severe oligohydramnios. The advent of fast imaging sequences in MRI technology has revolutionized the fetal morphological study, especially the use of multiplanar SSFSE (single-shot fast spin-echo) sequence which has improved not only the diagnosis but also the image quality. 

Additional contributor: R. Bouguelaa MD, Z. Boudiaf, MD.

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