Early imaging predictors of fetal cerebral ischemic injury in monochorionic twin pregnancy complicated by spontaneous single intrauterine death

Abstract

Objective Monochorionic twin pregnancies are at increased risk of single intrauterine death (sIUD) and subsequent brain injury in the surviving twin owing to shared placentation. We assessed the association between middle cerebral artery peak systolic velocity (MCA‐PSV) and cerebral injury on magnetic resonance imaging (MRI) and examined the association between cerebral findings on diffusion‐weighted imaging (DWI) and those on T2‐weighted imaging following spontaneous sIUD. Methods This was a retrospective cohort study of monochorionic pregnancies complicated by spontaneous sIUD followed at a tertiary center between January 2008 and January 2020. Pregnancies with sIUD following laser treatment, those with selective feticide, double IUD occurring on the same day or sIUD before 14 weeks' gestation were excluded, as were cases in which MCA‐PSV was not measured or DWI‐MRI was not performed. The ability of MCA‐PSV Doppler to predict subsequent cerebral injury on MRI was assessed, and DWI findings were analyzed and compared with those on susceptibility‐weighted imaging (SWI) and T2‐weighted MRI to determine its diagnostic accuracy. Results We assessed 64 monochorionic pregnancies complicated by spontaneous sIUD. Of these, 47 (73.4%) pregnancies underwent fetal brain MRI and met the inclusion criteria. Sixteen (34.0%) of these fetuses demonstrated cerebral injury on MRI. The median interval between the diagnosis of sIUD and MRI examination was 5 days. Fetuses with increased MCA‐PSV > 1.5 multiples of the median (MoM) following sIUD were significantly more likely to demonstrate cerebral injury on MRI than were those with normal MCA‐PSV (68.8% vs 38.7%; P = 0.05). The sensitivity and specificity of MCA‐PSV > 1.5 MoM for predicting cerebral injury on MRI were 68.8% (95% CI, 41.3–88.9%) and 61.3% (95% CI, 42.2–78.2%), respectively. Patterns of early cerebral injury on T2‐weighted and SWI‐MRI included acute or subacute tissue swelling (n = 6), parenchymal atrophy (n = 7), loss of cortical ribbon (n = 1) and hemorrhage (n = 8). Early MRI within approximately 2 weeks after the diagnosis of sIUD demonstrated abnormal DWI along with coexisting SWI and T2‐weighted sequelae in 56.3% (9/16) of cases. When DWI was normal and a second MRI examination was performed later (n = 7), there were no ischemic changes evident on T2‐weighted imaging. Conclusions Increased MCA‐PSV is associated with, but predicts poorly, cerebral injury after sIUD. Early MRI with DWI within approximately 2 weeks after the diagnosis of sIUD is valuable in identifying any cerebral injury. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal growth disorders in twin gestations

“…TTTS cases complicated by severe early onset FGR (and monochorionic twins with severe early onset FGR without TTTS) may be treated with selective fetal reduction to reduce the deleterious effect of in-utero demise on the surviving co-twin. Fetal reduction using either bipolar cord coagulation or radiofrequency ablation has an approximate 15% risk of pregnancy loss, which is less than the 30% risk of adverse outcomes in a surviving co-twin should demise occurs [48][49][50]. Recently, laser ablation of shared placental anastomoses in monochorionic twins complicated by FGR without TTTS has been described.…”

Twin Gestation With Spontaneous Reduction To Singleton

“…Recent studies have looked at antenatal MRI and its ability to predict a neurological prognosis in the setting of spontaneous sIUFD in MC gestations. One recent retrospective study found that of those with fetal brain MRI for the surviving twin, the rate of abnormal imaging was 34% 42 . Fetuses with severe cerebral injury on MRI following sIUFD were more likely to have an MCA-PSV >1.5MoM (68.8% vs. 38.7); however, a normal MCA-PSV did not rule out neurological injury 42 .…”

“…One recent retrospective study found that of those with fetal brain MRI for the surviving twin, the rate of abnormal imaging was 34% 42 . Fetuses with severe cerebral injury on MRI following sIUFD were more likely to have an MCA-PSV >1.5MoM (68.8% vs. 38.7); however, a normal MCA-PSV did not rule out neurological injury 42 . An elevated MCA alone was found to be poorly predictive of cerebral injury (sensitivity of 68.8% and specificity of 61%) 42 .…”

The Controversies and Challenges in the Management of Twin Pregnancy: From the Perspective of International Federation of Gynecology and Obstetrics Guidelines

“…If necessary, magnetic resonance imaging (MRI) should be performed 4 to 6 weeks later after fetal demise. 12,31 However, Shinar et al 49 found that although increased MCA-PSV may be a poor predictor of cerebral injury, early MRI within 2 weeks of sIUD is valuable to identify any cerebral injury with additional diffusion-weighted imaging. Thus, conservative surveillance is suggested when sIUD occurs prematurely, but the utility of MRI with diffusion-weighted imaging to detect brain injury needs more clinical trials.…”

“…If necessary, magnetic resonance imaging (MRI) should be performed 4 to 6 weeks later after fetal demise 12,31 . However, Shinar et al 49 . found that although increased MCA-PSV may be a poor predictor of cerebral injury, early MRI within 2 weeks of sIUD is valuable to identify any cerebral injury with additional diffusion-weighted imaging.…”