Abstract：
Twin reversed arterial perfusion (TRAP) sequence is a rare complication of monochorionic multiple gestation pregnancies, in which the pump twin provides hemodynamic support to a nonviable co-twin (acardius). Fetal magnetic resonance imaging (MRI) is used to detect pump twin abnormalities, particularly brain ischemia, prior to fetal intervention to interrupt umbilical blood flow to the acardius.
To summarize the imaging findings of TRAP sequence pregnancies in a large series.
A single-center retrospective review was performed of all TRAP sequence pregnancies referred for fetal MRI (2004-2021). Fetal MRI, ultrasound, and echocardiography data were collected.
Eighty-eight TRAP sequence pregnancies with MRI were included (mean gestational age, 19.8±2.8 weeks). Demise of the pump twin was noted in two pregnancies at the time of MRI. By MRI, 12% (10/86) of live pump twins had abnormalities, including 3% (3/86) with brain abnormalities and 9% (8/86) with extra-cranial abnormalities. By echocardiography, 7% (6/86) of pump twins had structural cardiac abnormalities. Three acardius morphological subtypes were identified by MRI: acephalus (55%, 48/88), anceps (39%, 34/88), and amorphous (7%, 6/88). The mean ultrasound acardius to pump twin ratio A/P ratio, calculated for each twin pair as the ratio of the acardius trunk (and head, if present) plus limb volume to the pump twin estimated fetal weight) differed among the three acardius subtypes (P=.03). The mean A/P ratio moderately correlated with pump twin cardiothoracic ratio and combined cardiac output (Pearson\'s r=0.45 and 0.48, respectively, both P<.001).
Fetal MRI of TRAP sequence pregnancies found anomalies in a substantial number of pump twins. The three acardius subtypes differed in A/P ratio, which moderately correlated with the pump twin cardiothoracic ratio and combined cardiac output.
To summarize the imaging findings of TRAP sequence pregnancies in a large series.
A single-center retrospective review was performed of all TRAP sequence pregnancies referred for fetal MRI (2004-2021). Fetal MRI, ultrasound, and echocardiography data were collected.
Eighty-eight TRAP sequence pregnancies with MRI were included (mean gestational age, 19.8±2.8 weeks). Demise of the pump twin was noted in two pregnancies at the time of MRI. By MRI, 12% (10/86) of live pump twins had abnormalities, including 3% (3/86) with brain abnormalities and 9% (8/86) with extra-cranial abnormalities. By echocardiography, 7% (6/86) of pump twins had structural cardiac abnormalities. Three acardius morphological subtypes were identified by MRI: acephalus (55%, 48/88), anceps (39%, 34/88), and amorphous (7%, 6/88). The mean ultrasound acardius to pump twin ratio A/P ratio, calculated for each twin pair as the ratio of the acardius trunk (and head, if present) plus limb volume to the pump twin estimated fetal weight) differed among the three acardius subtypes (P=.03). The mean A/P ratio moderately correlated with pump twin cardiothoracic ratio and combined cardiac output (Pearson\'s r=0.45 and 0.48, respectively, both P<.001).
Fetal MRI of TRAP sequence pregnancies found anomalies in a substantial number of pump twins. The three acardius subtypes differed in A/P ratio, which moderately correlated with the pump twin cardiothoracic ratio and combined cardiac output.
摘要：
背景：双反向动脉灌注（TRAP）序列是单绒毛膜多胎妊娠的罕见并发症，其中泵双胎为无活力的同胎（acardius）提供血液动力学支持。胎儿磁共振成像（MRI）用于检测泵双胎异常，尤其是脑缺血,在胎儿介入之前中断脐血流到心包。
目的：总结一系列TRAP序列妊娠的影像学表现。
方法：对所有接受胎儿MRI（2004-2021年）的TRAP序列妊娠进行单中心回顾性分析。胎儿核磁共振,超声，并收集超声心动图数据。
结果：纳入了88例经MRI检查的TRAP序列妊娠（平均胎龄，19.8±2.8周）。在进行MRI检查时，在两次怀孕中发现了双胎泵的死亡。通过核磁共振,12%(10/86)的活泵双胞胎有异常，包括3％（3/86）的脑异常和9％（8/86）的颅外异常。通过超声心动图,7%(6/86)的泵双生有结构性心脏异常。通过MRI确定了三种无心畸形形态亚型：无脑（55％，48/88），anceps(39%，34/88),和无定形(7%，6/88)。平均超声心痛与泵双比A/P比，为每对双胞胎计算为无心躯干(和头部，如果存在）加上泵双胎估计胎儿体重的肢体体积）在三种心包亚型之间有所不同（P=.03）。平均A/P比与泵双心胸比率和联合心输出量中度相关（Pearson\sr=0.45和0.48，分别两者P<.001)。
结论：TRAP序列妊娠的胎儿MRI在相当数量的泵双胎中发现异常。三种心痛亚型的A/P比不同，与泵双心胸比率和联合心输出量中度相关。
目的：总结一系列TRAP序列妊娠的影像学表现。
方法：对所有接受胎儿MRI（2004-2021年）的TRAP序列妊娠进行单中心回顾性分析。胎儿核磁共振,超声，并收集超声心动图数据。
结果：纳入了88例经MRI检查的TRAP序列妊娠（平均胎龄，19.8±2.8周）。在进行MRI检查时，在两次怀孕中发现了双胎泵的死亡。通过核磁共振,12%(10/86)的活泵双胞胎有异常，包括3％（3/86）的脑异常和9％（8/86）的颅外异常。通过超声心动图,7%(6/86)的泵双生有结构性心脏异常。通过MRI确定了三种无心畸形形态亚型：无脑（55％，48/88），anceps(39%，34/88),和无定形(7%，6/88)。平均超声心痛与泵双比A/P比，为每对双胞胎计算为无心躯干(和头部，如果存在）加上泵双胎估计胎儿体重的肢体体积）在三种心包亚型之间有所不同（P=.03）。平均A/P比与泵双心胸比率和联合心输出量中度相关（Pearson\sr=0.45和0.48，分别两者P<.001)。
结论：TRAP序列妊娠的胎儿MRI在相当数量的泵双胎中发现异常。三种心痛亚型的A/P比不同，与泵双心胸比率和联合心输出量中度相关。
