Preliminary study of MRI and ultrasound in multi-pregnancies complicated by twin reversed arterial perfusion sequence
ZHU Xiang-yang1, CHEN Xin-lin1, YANG Xiao-hong1, YANG Wen-zhong1, SUN Zi-yan2, FENG Qian1, GE Qian1
1. Hubei Maternity and Child Health Hospital, Wuhan 430070, China;2. Tongji Hospital, Tongji Medical College, Huangzhong University of Science and Technology, Wuhan 430030, China
Abstract：Objective: To preliminarily study ultrasound and MRI in multi-pregnancies complicated by twin reversed arterial perfusion sequence(TRAP). Methods: Twelve TRAP cases from 2005 to 2013 diagnosed by ultrasound and additionally examined by MRI were included in this study. The imaging of ultrasound and MRI were reviewed retrospectively and at the same time the imaging findings were correlated with autopsy specimens of 4 acardiac twins and 3 pump twins. Results: The 12 TRAP cases had acardia and the complications included 5 acephalus, 4 anceps(some cranial structures and brain tissue is present), 3 undecided type malformations. Eleven cases had subcutaneous edema, 9 cases had single umbilical artery. Ultrasound can make the diagnosis of acardia clearly except misdiagnosis in 2 cases at the beginning. Color flow Doppler ultrasound can estimate the direction of blood flow of the acardiac twin and the cardiac function of the pump twin, and 3 pump twins had cardiac dysfunction. Ultrasound displayed cases not diagnosed by MRI included 1 case of paper fetus, 1 GA 16 weeks acardiac twin with anomalies of upper and lower limbs and 1 GA 24 weeks acardiac twin with anomaly toes. MRI can display the profile of the acardiac and pump twin clearly with good spatial resolution, also can demonstrate severe malformation of the acardiac twin. MRI displayed the relationship of the twin fetuses and the umbilical cord in one case and the limbs of the acardiac twin in 2 cases which can not be showed by ultrasound. Conclusion: Ultrasound and MRI are both available to assess TRAP objectively. Ultrasound has advantages in real-time dynamic and repeatability which can distinguish the detailed deformity, provide the blood circulation characteristics of the acardiac twin and estimate the cardiac function of the pump twin. MRI has advantages in large view which can display the spatial orientation of the twin clearly, placenta/amniotic fluid and the relationship of the umbilical cord with the placenta. Combining the two imaging technology will further display the structure, function of TRAP and the pathological changes which are important for prenatal diagnosis and treatment.
2014, Vol. 25 
