Diagnosis of fetal neural tube defects by MRI

Abstract

Objective To explore the diagnostic value of MRI on fetal neural tube defects.Methods Ten pregnant women,aged from 25 to 35 years(average 28 years)and with gestation from 20-39 weeks(average 33 weeks)were studied with a 1.5 T superconductive MR unit within 24 to 48 hours after ultrasound(US)studies.The imaging protocol included fast-imaging employing steady-state acquisition,single-shot FSE and T_1-weighted fast inversion recovery motion insensitive sequences in the axial,frontal,and sagittal planes relative to the fetal brain,thorax,abdomen,and spines.Prenatal US and MRI findings were compared with postnatal MRI diagnoses(3 fetuses)or autopsy(7 fetuses).Results Ten pregnant women(9 with a single fetus and 1 with twin fetuses)were examined.For all cases,the diagnoses established by MRI were correct when compared with postnatal diagnosis or autopsy.In 7 cases,US and MRI findings were in complete agreement with postnatal diagnoses.US missed the diagnosis in 1 case and misdiagnosed in 2 cases.Ten neural tube defects in this study included anencephaly(1 case),exencephaly (1 case),meningoencephalocele associated with amniotic band sequence(1 case),meningocele(1 case),thoracic myelomeningocele(1 case),lumbar spinal bifida(1 case),sacroiliac myelomeningocele(2 cases),sacroiliac large cystic spinal meningocele(1 case),sacroiliac spinal bifida(1 case).Conclusions Prenatal MRI is effective in the assessment of fetal neural tube defects.It can exactly discriminate herniated contents and locate the spinal lesion level. Key words: Fetus; Neural tube defects; Magnetic resonance imaging; Ultrasonography