Third Trimester Structural and Diffusion Brain Imaging after Single Intrauterine Fetal Death in Monochorionic Twins: MRI-Based Cohort Study

Abstract

BACKGROUND AND PURPOSE: Single intrauterine fetal death increases the risk of antenatal brain lesions in the surviving twin. We evaluated the prevalence of structural brain lesions, biometry, and diffusivity on routine third trimester MR imaging performed following single intrauterine fetal death. MATERIALS AND METHODS:In a retrospective MR imaging-based cohort study, we compared 29 monochorionic twins complicated with single intrauterine fetal death (14 following laser ablation treatment for twin-to-twin transfusion syndrome, 8 following selective fetal reduction, and 7 spontaneous) with 2 control cohorts (49 singleton fetuses and 28 uncomplicated twin fetuses). All fetuses in the single intrauterine fetal death group underwent fetal brain MR imaging as a routine third trimester evaluation. Structural brain lesions were analyzed. Cerebral biometry and diffusivity were measured and compared.RESULTS: Brain lesions consistent with the evolution of prior ischemic injury were found in 1 of 29 fetuses, not detected by ultrasound. No acute brain infarction, hemorrhage, or cortical abnormalities were found. Supratentorial biometric measurements in the single intrauterine fetal death group were significantly smaller than those in the singleton group, but not significantly different from those in the uncomplicated twin group. There were no significant differences in ADC values of the cerebral hemispheres, basal ganglia, and pons between the single intrauterine fetal death group and either control group.CONCLUSIONS: Although smaller brain biometry was found, normal diffusivity in surviving twins suggests normal parenchymal microstructure. The rate of cerebral structural injury was relatively low in our cohort, arguing against the routine use of fetal brain MR imaging in twin pregnancies complicated with single intrauterine fetal death. Larger prospective studies are necessary to guide appropriate surveillance protocol and parental counseling in twin pregnancies complicated by single intrauterine fetal death.

The Current Knowledge of Cerebral Magnetic Resonance Imaging in Monochorionic Twins: A Systematic Review of the Last 20 Years

“…Twelve out of twenty-three studies described fetal MRI findings in surviving MC co-twins after sIUFD [8,13,14,16,23,25,26,[28][29][30]. This resulted in the second largest group studied with fetal MRI, with brain imaging findings reported in 862 fetuses.…”

“…Of note, in 111 cases, sIUFD was caused by selective fetal reduction. The studies reported a median overall incidence of cerebral injury in single survivors of 28.3% (range 0-55%) after sIUFD [8,13,14,16,17,23,25,26,[28][29][30]. We made a distinction between studies with single survivors after selective fetal reduction and other causes of sIUFD because of the different mechanisms of cerebral injury.…”

“…The following four studies also included single survivors after selective fetal reduction [8,13,17,28]. These studies reported a median incidence of cerebral injury in single survivors, including survivors after selective fetal reduction, of 16.5% (3.4-30.2%) after sIUFD.…”

“…Both fetal and neonatal magnetic resonance imaging (MRI) can be used to detect cerebral injury, allowing for early diagnosis, counseling parents, and planning further management [7]. Fetal MRI provides detailed information about early brain development, maturation, and the presence of antenatal brain injury [8,9]. Neonatal MRI can show already established fetal brain injury but also injury due to perinatal and postnatal complications.…”

“…Neonatal MRI can show already established fetal brain injury but also injury due to perinatal and postnatal complications. There is limited information available in the current literature regarding the use of MRI concerning cerebral injury, structural brain development, and neurodevelopmental outcomes in complicated MC twin pregnancies [8].…”