Prenatal diagnosis of sirenomelia with 3D skeletal ultrasound mode imaging, 3D spiral CT and MRI / 中华医学超声杂志（电子版）

ABSTRACT

ObjectiveTo explore the clinical value of three-dimensional (3D) skeletal ultrasound mode imaging, 3D helical computer tomography (3D-HCT) and MRI in diagnosing lower limb skeletal malformations of fetal sirenomelia.MethodsSeven fetuses were suspected of sirenomelia with routine prenatal ultrasonography examination. Three-dimensional skeletal ultrasound mode imaging and MRI were used to conifrm the diagnosis, and the results were compared to those of pathology, 3D spiral CT or X-ray after termination. Five of them underwent chromosome examination including chorionic villus or umbilical cord biopsy.ResultsSix fetuses were singletons and one fetus was a conjoined twin. Three fetuses were male, while four fetuses were female. All fetuses with sirenomelia showed varying degrees of skeletal abnormalities 1 case of typeⅢ, 2 cases of typeⅣ, 3 cases of typeⅤ and 1 case of typeⅥ. No foot was detected in one case and only single foot was detected in other 6 cases. In 7 cases, 3D skeletal ultrasound mode imaging could demonstrate all the lower limb skeletal malformations, including abnormal femur and tibioifbula, single foot or no feet. Prenatal MRI could demonstrate abnormal femur in 4 cases, abnormal tibioifbula in 1case, and no foot malformation. The results of 3D spiral CT after termination were consistent with X-ray and pathological examination results.ConclusionsAs a new imaging technology for detecting fetal skeletal malformations, prenatal 3D skeletal ultrasound mode imaging and postnatal 3D spiral CT both can display fetal bone clearly. They both have important clinical value in diagnosing lower limb skeletal malformations.