In this variant, multiple gestations of all chorionicity and amnionicity have a known abnormality detected on a previous examination and are receiving surveillance imaging. MRI Fetal Without and With IV Contrast MRI fetal without and with IV contrast does not have a role in growth and antepartum surveillance of MC, DC, or multichorionic gestations. Gadolinium contrast is usually not administered for fetal indications. MRI Fetal Without IV Contrast MRI fetal without IV contrast can be useful for antepartum surveillance for a known abnormality. In DC and multichorionic twins, this can be indicated for multiple reasons, in particular, to evaluate neurologic, thoracic, and abdominal structural anomalies and associated complications. In MC twins, fetal MRI has been useful in the assessment of intracranial injury that may occur related to TTTS after fetal intervention or following spontaneous in utero demise of a co-twin. Cerebral injury can affect approximately 18% of co-twin survivors after single fetal demise in MC twin pregnancies, and follow-up evaluation of these cases can improve detection rate of such damage [65,66]. MRI evaluation of complicated MC multiple gestations can be useful for estimating neurologic injury associated with TTTS, TAPS, sFGR, and fetal interventions [65]. In a study, postnatal follow-up of all survivors shown to have normal fetal MRI demonstrated normal neurologic outcome, but only 1 of 3 survivors with cerebral lesions at fetal MRI demonstrated normal neurologic outcome [65]. Brain injury of the surviving co-twin after single fetal demise in MC pregnancies is usually of ischemic origin and spares the brainstem and cerebellum [67]. Focal brain lesions are more frequent in pregnancies complicated by TTTS or in Multiple Gestations those in whom an intervention has been performed [67]. Robinson et al [18] showed that MRI provided additional information over a prenatal US in 5 of 33 patients (15%) altering prognosis and patient counseling.
Multiple Gestations. In this variant, multiple gestations of all chorionicity and amnionicity have a known abnormality detected on a previous examination and are receiving surveillance imaging. MRI Fetal Without and With IV Contrast MRI fetal without and with IV contrast does not have a role in growth and antepartum surveillance of MC, DC, or multichorionic gestations. Gadolinium contrast is usually not administered for fetal indications. MRI Fetal Without IV Contrast MRI fetal without IV contrast can be useful for antepartum surveillance for a known abnormality. In DC and multichorionic twins, this can be indicated for multiple reasons, in particular, to evaluate neurologic, thoracic, and abdominal structural anomalies and associated complications. In MC twins, fetal MRI has been useful in the assessment of intracranial injury that may occur related to TTTS after fetal intervention or following spontaneous in utero demise of a co-twin. Cerebral injury can affect approximately 18% of co-twin survivors after single fetal demise in MC twin pregnancies, and follow-up evaluation of these cases can improve detection rate of such damage [65,66]. MRI evaluation of complicated MC multiple gestations can be useful for estimating neurologic injury associated with TTTS, TAPS, sFGR, and fetal interventions [65]. In a study, postnatal follow-up of all survivors shown to have normal fetal MRI demonstrated normal neurologic outcome, but only 1 of 3 survivors with cerebral lesions at fetal MRI demonstrated normal neurologic outcome [65]. Brain injury of the surviving co-twin after single fetal demise in MC pregnancies is usually of ischemic origin and spares the brainstem and cerebellum [67]. Focal brain lesions are more frequent in pregnancies complicated by TTTS or in Multiple Gestations those in whom an intervention has been performed [67]. Robinson et al [18] showed that MRI provided additional information over a prenatal US in 5 of 33 patients (15%) altering prognosis and patient counseling.