Prenatal MRI of Congenital Abdominal and Chest Wall Defects

When Closure Fails: What the Radiologist Needs to Know About the Embryology, Anatomy, and Prenatal Imaging of Ventral Body Wall Defects

“…20 At most institutions, prenatal MRI is performed on 1.5-T scanners, preferentially equipped with an advanced spatial encoding gradient system, allowing for fast data acquisition (o400 ms/slice, to reduce fetal motioninduced artifacts and image degradation during acquisition), and with high-resolution capabilities (matrix size up to 512). 24 Imaging protocols to assess VBWDs include fast-scan techniques, such as T2-weighted ultrafast spin-echo sequences in 3 orthogonal planes of the fetal body; gradient-echo T1-weighted imaging is also used as an adjunct to verify meconium in the bowel and to assess the liver.…”

“…24 Imaging protocols to assess VBWDs include fast-scan techniques, such as T2-weighted ultrafast spin-echo sequences in 3 orthogonal planes of the fetal body; gradient-echo T1-weighted imaging is also used as an adjunct to verify meconium in the bowel and to assess the liver. 20,25 Limitations on prenatal MRI include fetal movements and maternal breathing movements. Fetal movements are dependent on gestational age and the available space, thus tending to be more pronounced in young fetuses and in the setting of polyhydramnios; in most cases, however, it is possible to continue the study by repeating sequences in the most favorable plane.…”

“…This herniation usually occurs at the base of the umbilical cord, the cord insertion being located at the apex of the herniated sac, which contains variable amounts of different visceral organs, usually bowel or liver or both. 15,20 In this sense, they can be categorized as either liver-containing (giant) omphaloceles (Fig. 3) or non-liver-containing omphaloceles (containing only bowel in the defect) (Fig.…”

“…Gastroschisis is a sporadic anomaly with a prevalence of 1-6 per 3000-10,000 live births, 20 and in most western countries, it has been increasing over the past few decades. 8 Children of young mothers are more susceptible, and some environmental risk factors (such as drugs and medications) are suspected to be involved.…”

“…Usually, only bowel loops are free-floating and, the presence of associated extracorporeal solid organs, without a limiting membrane, may otherwise indicate a ruptured omphalocele. 20 The amount of eviscerated bowel is variable and may appear disproportionately large relative to the abdominal circumference, which is reduced in size. Small bowel is always herniated with or without large bowel.…”