Additional findings on MRI included occipital lobe infarction, hemispheric injury, dural sinus thrombosis, polymicrogyria, and intraventricular hemorrhage. In this series, US was normal in 2 patients and underrepresented parenchymal injury in the remaining 3 patients [18]. Kocaoglu et al [68] demonstrated that abnormal cerebral imaging findings on MRI due to hypoxic-ischemic injury or hemorrhage can be seen at the beginning of the second trimester and do not correlate with the current US staging system; however, they do correlate with decreased survival. Hence, it has been suggested that fetal MRI-based detection of cerebral abnormalities could be included in the TTTS staging system as an independent risk factor and incorporated in the prenatal evaluation of complicated MC gestations [68]. In a study including 49 MC multiple gestations with single fetal demise, median gestational age at time of co-twin death was 25 weeks and median interval between single fetal loss and live birth was 61 days, with median gestational age at delivery 36 weeks [17]. Severe cerebral injury was diagnosed in 26% of the survivors and was detected antenatally on MRI in 4 of 50 (8%) cases. Abnormal cerebral findings predominantly resulted from hypoxic- ischemic injury resulting in cystic periventricular leukomalacia, MCA infarction, or injury to basal ganglia, thalamus, and/or cortex [17]. Risk factors associated with severe cerebral injury were advanced gestational age at time of single fetal demise, development of TTTS before co-twin loss, and lower gestational age at birth [17]. US Assessment for TTTS DC twins with separate placentas do not typically develop TTTS or other complications associated with a single shared placenta. Hence, this evaluation is not useful for growth and antepartum surveillance of complicated DC or multichorionic twins.
Multiple Gestations. Additional findings on MRI included occipital lobe infarction, hemispheric injury, dural sinus thrombosis, polymicrogyria, and intraventricular hemorrhage. In this series, US was normal in 2 patients and underrepresented parenchymal injury in the remaining 3 patients [18]. Kocaoglu et al [68] demonstrated that abnormal cerebral imaging findings on MRI due to hypoxic-ischemic injury or hemorrhage can be seen at the beginning of the second trimester and do not correlate with the current US staging system; however, they do correlate with decreased survival. Hence, it has been suggested that fetal MRI-based detection of cerebral abnormalities could be included in the TTTS staging system as an independent risk factor and incorporated in the prenatal evaluation of complicated MC gestations [68]. In a study including 49 MC multiple gestations with single fetal demise, median gestational age at time of co-twin death was 25 weeks and median interval between single fetal loss and live birth was 61 days, with median gestational age at delivery 36 weeks [17]. Severe cerebral injury was diagnosed in 26% of the survivors and was detected antenatally on MRI in 4 of 50 (8%) cases. Abnormal cerebral findings predominantly resulted from hypoxic- ischemic injury resulting in cystic periventricular leukomalacia, MCA infarction, or injury to basal ganglia, thalamus, and/or cortex [17]. Risk factors associated with severe cerebral injury were advanced gestational age at time of single fetal demise, development of TTTS before co-twin loss, and lower gestational age at birth [17]. US Assessment for TTTS DC twins with separate placentas do not typically develop TTTS or other complications associated with a single shared placenta. Hence, this evaluation is not useful for growth and antepartum surveillance of complicated DC or multichorionic twins.