Conjoined twins: Radiological experience

Postnatal imaging of conjoined twins: a customized multimodality approach

Medical imaging plays a crucial role in the management of conjoined twins. The role of imaging is to explore the anatomy, outline the shared organs and determine whether surgery is feasible. It also serves as a roadmap for successful separation. Additionally, imaging helps with counseling parents about prognosis. This review aims to illustrate recent advances in different imaging modalities and their role in the management of the various types of conjoined twins with an emphasis on relevant tips for optimal imaging.

Prenatal and postnatal radiologic evaluation of conjoined twins

Imaging of conjoined twins requires the use of multiple modalities, in both the prenatal and postnatal setting. Prenatal imaging, including both ultrasound and magnetic resonance imaging, benefits from an organized, worksheet-based approach, careful labelling of all images, and adoption of supplemental techniques. Postnatal imaging should be informed by the prenatal imaging findings and should be thoughtfully planned prior to performance. Complete evaluation prior to planned surgical separation will require the use of complementary modalities and multidisciplinary review and discussion.

Prenatal sonographic diagnosis of cephalopagus conjoined twins at 14 weeks of pregnancy

Conjoined twins are extremely rare and are a type of monozygotic twins that occur due to an incomplete embryonic division on postconception day 13 to 15. Eight different types of conjoined twins have been described in the literature. Management of the condition depends on the site and extent of the union. We present a case of cephalopagus twins diagnosed at 14 weeks of gestation.

Freeform fabrication of tissue-simulating phantom for potential use of surgical planning in conjoined twins separation surgery

Preoperative assessment of tissue anatomy and accurate surgical planning is crucial in conjoined twin separation surgery. We developed a new method that combines three-dimensional (3D) printing, assembling, and casting to produce anatomic models of high fidelity for surgical planning. The related anatomic features of the conjoined twins were captured by computed tomography (CT), classified as five organ groups, and reconstructed as five computer models. Among these organ groups, the skeleton was produced by fused deposition modeling (FDM) using acrylonitrile-butadiene-styrene. For the other four organ groups, shell molds were prepared by FDM and cast with silica gel to simulate soft tissues, with contrast enhancement pigments added to simulate different CT and visual contrasts. The produced models were assembled, positioned firmly within a 3D printed shell mold simulating the skin boundary, and cast with transparent silica gel. The produced phantom was subject to further CT scan in comparison with that of the patient data for fidelity evaluation. Further data analysis showed that the produced model reassembled the geometric features of the original CT data with an overall mean deviation of less than 2 mm, indicating the clinical potential to use this method for surgical planning in conjoined twin separation surgery.