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Diagnostic Techniques and Criteria for First-Trimester Conjoined Twin Documentation: A Review of the Literature Illustrated by Three Recent Cases

Baken, Leonie MSc*; Rousian, Melek MD, PhD; Kompanje, Erwin J. O. MD, PhD‡§; Koning, Anton H. J. PhD; van der Spek, Peter J. PhD; Steegers, Eric A. P. MD, PhD#; Exalto, Niek MD, PhD**

Obstetrical & Gynecological Survey: November 2013 - Volume 68 - Issue 11 - p 743–752
doi: 10.1097/OGX.0000000000000000
CME Articles: First-Trimester Conjoined Twin Documentation

Objectives Conjoined twins are rare. High-quality imaging techniques are essential for proper first-trimester diagnosis. Technological development leads to new imaging techniques such as 3-dimensional virtual embryoscopy. The aim of this review was to explore imaging techniques used in the first-trimester diagnosis of conjoined twins and provide a systematic diagnostic table for making this diagnosis.

Design A PubMed literature search was performed using the terms ultrasound, Doppler, MRI, and CT combined with first-trimester and conjoined twins. Three recent cases at our department are reviewed and examined additionally using 3-dimensional virtual embryoscopy.

Results The different types of conjoined twins are summarized in a table for practical use during ultrasound examination. In evaluating conjoined twins, 2-dimensional ultrasound is the criterion standard. Three-dimensional and Doppler ultrasounds add anatomical and prognostic information. Virtual embryoscopy imaging reveals additional findings in our 3 cases not seen with routine 2-dimensionalultrasound examination.

Conclusions Each case of conjoined twins is unique and should be evaluated with the best possible imaging techniques. Three-dimensional and Doppler ultrasound should be added to the systematic diagnostic evaluation of conjoined twins. Virtual embryoscopy imaging may contribute to earlier, more appropriate counseling and management of these pregnancies.

Target Audience: Obstetricians and gynecologists, family physicians

Learning Objectives: After completing this CME activity, physicians should be better able to differentiate between the different types of conjoined twins and their prognosis, compare the different imaging techniques used for the evaluation of conjoined twins to decide whether additional diagnostic imaging techniques are useful in an individual case, and evaluate complex cases, such as conjoined twins, using new imaging techniques.

*PhD Student and †Resident, Division of Obstetrics and Prenatal Medicine, Department of Obstetrics and Gynaecology, and ‡Senior Researcher, Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam; and §Curator, Collection Human and Non-Human Dysmorphology, Natural History Museum Rotterdam; and ∥Associate Professor and ¶Professor, Department of Bioinformatics, Erasmus MC, University Medical Center Rotterdam; and #Professor and **Associate Professor, Division of Obstetrics and Prenatal Medicine, Department of Obstetrics and Gynaecology, Rotterdam, the Netherlands Netherlands

This research was financially supported by Erasmus Trustfonds, Erasmus MC vriendenfonds, Meindert de Hoop foundation, and Fonds NutsOhra.

The authors have disclosed that the V-Scope software has not been approved by the U.S. Food and Drug Administration.

All authors and staff in a position to control the content of this CME activity and their spouses/life partners (if any) have disclosed that they have no financial relationships with, or financial interests in, any commercial organizations pertaining to this educational activity.

Correspondence requests to: Leonie Baken, MSc, Department of Obstetrics and Gynaecology, Division of Obstetrics and Prenatal Medicine, Erasmus MC University Medical Centre Rotterdam, Room NA15.23, PO Box 2040, 3000 CA Rotterdam, the Netherlands. E-mail:

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© 2013 by Lippincott Williams & Wilkins.