High-intensity focused ultrasound treatment for twin reversed arterial perfusion sequence

Twin reversed arterial perfusion (TRAP) sequence is a serious complication of monochorionic twin pregnancies, in which arterioarterial anastomoses allow blood flow from a 'pump' fetus to an acardiac fetus via reversed flow in the latter's umbilical artery. Several trial treatments for TRAP sequence have been reported, but all of these have been invasive. We present a case of TRAP sequence in which high-intensity focused ultrasound (HIFU) was applied to the umbilical artery of the anomalous twin at 26 weeks as a non-invasive fetal therapy. The HIFU intensity was set at approximately 2300 W/cm(2) with exposure periods of 10 s. Color Doppler ultrasound showed a decrease in blood supply to the anomalous twin, although complete occlusion of the targeted vessel was not achieved. Delivery was by Cesarean section at 29 weeks' gestation and the pump twin survived, without severe clinical complications at 6 months. Copyright ? 2012 ISUOG. Published by John Wiley & Sons, Ltd.     

Tailored management of twin reversed arterial perfusion (TRAP) sequence.

OBJECTIVE: To describe our management of pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence. METHODS: This was a retrospective study involving all cases of TRAP sequence referred to our fetal medicine unit in a 3-year period (2000-2002). Patients were routinely managed by repeat sonographic surveillance with sonographic anatomical evaluation and detailed echocardiography. Cases with signs of impending cardiac failure were treated by in-utero YAG-laser coagulation of the umbilical vessels of the acardiac twin. RESULTS: Six cases were studied. Three patients in whom there were no signs of deterioration in the status of the pump twin, and in whom the acardiac twin was smaller than the pump twin, were managed conservatively. However, one of these with monoamniotic twins ended in intrauterine fetal death of the pump twin. The other two cases presented with spontaneous cessation of blood flow in the umbilical artery of the acardiac twin. Both delivered at term normal neonates whose follow-up revealed no signs of neurological sequelae. One case of quadruplet pregnancy (with TRAP sequence and two dichorionic twins) was treated by selective termination of the monochorionic twins. Two cases with signs of impending cardiac failure were treated by in-utero YAG-laser occlusion of the vessels in the acardiac mass. Both interventions had a favorable outcome. CONCLUSIONS: Conservative treatment is suitable for milder cases of TRAP sequence in which the pump twin is the larger one. Cases in which the acardiac twin is larger have a poorer prognosis and should be treated by invasive intervention and cord occlusion.     

早孕期双胎反向动脉灌注序列征的产前超声诊断

目的总结早孕期（孕8~13⁺⁶周）双胎反向动脉灌注序列征（TRAPS）的超声表现及自然病程。 方法回顾性分析2001年5月至2020年12月于湖北省妇幼保健院产前超声诊断并经引产后或产后病理证实的早孕期TRAPS 75例，总结其早孕期超声特点及妊娠结局。 结果75例TRAPS中70例为双胎妊娠，5例为三胎妊娠。早孕期TRAPS超声声像图特点为：4例孕8~10周误诊为单胎妊娠，孕12~13⁺⁶周随访检查时诊断为双胎之一无心畸形。5例孕9~10⁺³周外院超声提示双胎之一“停育”，随访观察双胎之一“停育”的胎儿体积增大，与泵血儿（与孕龄相符）相比小0⁺⁴~2⁺¹周，增大的胎儿可见胎动或肢体活动。无心畸胎儿58例无心脏结构及心管搏动，胎儿结构少伴多种严重畸形，17例有心脏遗迹和心管搏动，胎儿结构发育相对较好。17例无心胎儿淋巴水囊肿，3例颈项透明层增厚，55例未见明显水肿。彩色多普勒超声显示39例无心畸胎通过单一脐动脉反向灌注朝向无心畸胎儿体内。14例无心畸胎后期（妊娠12⁺³~16周）复查出现血流自然阻断，表现为无心畸胎与胎盘间细线样结构。泵血儿67例解剖结构正常，5例合并心脏畸形，1例唇裂，2例水肿，17例心功能不全（1例后期好转）。结局及预后为：75例TRAPS中，正常分娩15例泵血儿，其中12例泵血儿存活，3例新生儿死亡；19例因孕12⁺⁵~19周宫内双死胎、16例因心功能不全、1例因孕17周胎膜早破、8例因合并泵血儿畸形最终均引产，另16例家属选择引产。 结论早孕期TRAPS有其特征性的超声表现，经腹部联合经阴道超声，同时结合彩色多普勒的特殊血流表现及动态观察有助于早期明确诊断。     

Twin reversed arterial perfusion (TRAP) syndrome

Twin reversed arterial perfusion (TRAP) syndrome is an extremely rare manifestation of feto-fetal transfusion syndrome. This condition is seen in monozygotic twin pregnancies, where the affected twin is perfused retrogradely by the healthy twin. The affected twin presents with bizarre malformations such as acardia and acephalus. We present such a case, which was diagnosed prenatally. The pregnancy progressed uneventfully to term.     

Radiofrequency ablation as a minimally invasive procedure in the treatment of twin reversed arterial perfusion sequence in twin pregnancy

Twin reversed arterial perfusion sequence is a rare anomaly of monochorionic multiple pregnancies affecting 1 of 35,000 pregnancies and 1% of monochorionic twin pregnancies. In this condition the affected twin has lethal malformations including poor or absent heart development and is reversely perfused by a structurally normal co‐twin. We report a case of a 21‐year‐old woman with a monochorionic twin pregnancy affected by twin reversed arterial perfusion sequence. This case highlights the therapeutic options and the management by radiofrequency ablation, which has been shown to be an easy and reliable technique with a high success rate compared with technically demanding fetoscopic procedures. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2013     

Diagnosis of twin reversed arterial perfusion sequence in the first trimester by transvaginal color Doppler ultrasound.

A case of twin reversed arterial perfusion (TRAP) sequence was diagnosed at 12 weeks' gestation using transvaginal color Doppler ultrasound, which demonstrated the presence of retrograde perfusion in the umbilical artery of the abnormal twin. Ultrasound imaging showed a monochorionic-diamniotic twin pregnancy with an inappropriately grown second twin, the morphological evaluation of which revealed an abnormal cephalic pole with acrania, diffuse subcutaneous edema and the presence of cardiac activity in an abnormal heart with a single chamber.     

超声诊断双胎反向动脉灌注序列征1例

<正>孕妇,28岁,孕23周,来我院行胎儿产前系统超声检查。超声检查:可见一形态学正常胎儿,双顶径59 mm,头围221 mm,腹围197 mm,股骨长37 mm,肱骨长36 mm,羊水无回声区最大深度74 mm,内未见明显羊膜带状回声,后壁胎盘厚约29 mm、Ⅰ级。胎心率131次/min,可见脐静脉搏动征,脐动脉S/D 2.13(图1)。胎儿颅骨光环完整,颈部皮肤褶皱层厚9 mm,颜面部正     

Endoscopic laser coagulation of umbilical cord vessels in twin reversed arterial perfusion sequence.

In monozygotic twin pregnancies with reversed arterial perfusion (TRAP) sequence, the donor twin is ut high risk of perinatal death. This paper describes the use of endoscopic surgery in the management of this condition. In four cases of TRAP sequence presenting at 17, 20, 26 and 28 weeks' gestation, respectively, an endoscope was introduced into the uterus under local anesthesia and a Nd-YAG laser was used to coagulate the umbilical cord vessels of the acardiac twin. Laser coagulation was successful in arresting blood flow to the acardiac fetus in the cases treated at 17 and 20 weeks, and healthy infants were delivered at term. In the pregnancies treated at 26 and 28 weeks, the umbilical cords were very edematous and laser coagulation failed to arrest blood flow; healthy infants were delivered after spontaneous labor at 29 weeks. These findings suggest that, during mid-gestation, endoscopic laser coagulation of the umbilical cord vessels of the acardiac twin is an effective method of treating TRAP sequence. In later pregnancy, alternative methods of treatment are needed.     

Transvaginal ultrasound diagnosis of twin reversed arterial perfusion syndrome at 9 weeks' gestation.

Diagnosis of twin reversed arterial perfusion syndrome was made using transvaginal sonography at 9 weeks' gestation. The morphological evaluation of the abnormal twin revealed a dysmorphic cephalic pole and absence of the upper extremities. There was diffuse subcutaneous edema and no detectable cardiac activity. The other twin had a normal appearance and a size compatible with the gestational age. The fetuses were divided by a thin amniotic membrane with normal amniotic fluid in both sacs. Diagnosis was confirmed by demonstrating fetal growth and lower limb activity in the abnormal twin 10 days later.     

产前超声诊断三胎妊娠伴双胎无心脐动脉反向灌注序列征

目的总结三胎妊娠伴双胎无心脐动脉反向灌注序列征（TRAPS）胎儿产前超声图像特点。 方法对2001年4月至2017年4月经湖北省妇幼保健院产前超声诊断和生后检查确诊的6例三胎妊娠伴TRAPS胎儿超声与病理检查结果进行对照分析,总结TRAPS胎儿产前超声图像特点。 结果产前超声显示：（1）6例三胎妊娠伴TRAPS胎儿中无心畸胎均有发育不良的下肢（1例有发育不良上肢）,无胸腔、无心脏结构及心管搏动,5例无头颅结构,1例有发育不良头;4例有脊柱和腹腔结构;4例为单脐动脉,5例伴全身皮肤水肿;彩色多普勒示脐动脉反向灌注朝向胎儿体内,2例产前超声末显示脐动脉及胎儿体内血流。（2）6例泵血儿解剖结构均正常,羊水过多2例,羊水正常4例。胎儿期发生心功能不全3例（1例中孕早期好转存活,2例宫内死胎）。（3）6例第三胎儿中5例解剖结构正常,1例多发畸形。胎儿预后：6例三胎妊娠伴TRAPS胎儿中1例剖宫产产下2个正常男婴,1个死胎（无心畸胎）;其余5例三胎均预后不良（5例泵血儿中4例宫内死胎,1例早产死亡;5例第三胎儿中1例宫内死胎,2例早产死亡,2例引产;5例无心畸胎中4例宫内血流阻断,1例生后死胎）。产后病理检查显示6例均为三胎妊娠伴TRAPS,其中4例为双绒毛膜三羊膜三胎妊娠,1例为双绒毛膜双羊膜三胎妊娠;1例为单绒毛膜三羊膜三胎妊娠。 结论三胎妊娠伴TRAPS为罕见而严重的多胎妊娠并发症,产前超声有特有的声像图特点,彩色多普勒超声有较高的诊断价值。     

Using the acoustic interference pattern to locate the focus of a high-intensity focused ultrasound (HIFU) transducer

One of the main problems encountered when using conventional B-mode ultrasound (US) for targeting and monitoring purposes during ablation therapies employing high-intensity focused US (HIFU) is the appearance of strong interference in the obtained diagnostic US images. In this study, instead of avoiding the interference noise, we demonstrate how we used it to locate the focus of the HIFU transducer in both in vitro tissue-mimicking phantoms and an ex vivo tissue block. We found that when the B-mode image plane coincided with the HIFU focal plane, the interference noise was maximally converged and enhanced compared with the off-focus situations. Stronger interference noise was recorded when the angle (alpha) between the US image plane and the HIFU axis was less than or equal to 90 degrees. By intentionally creating a target (group of bubbles) at the 3.5-MHz HIFU focus (7.1 mm in length and 0.7 mm in diameter), the position of the maximal noise convergence coincided well with the target. The difference between the predicted focus and the actual one (bubbles) on x and z axes (axes perpendicular to the HIFU central axis, Fig. 1) were both about 0.9 mm. For y axis (HIFU central axis), the precision was within 1.0 mm. For tissue block ablation, the interference noise concentrated at the position of maximal heating of the HIFU-induced lesions. The proposed method can also be used to predict the position of the HIFU focus by using a low intensity output scheme before permanent changes in the target tissue were made.     

Application of high-intensity focused ultrasound for fetal therapy: experimental study using an animal model of lower urinary tract obstruction

Objective

The purpose of this study is to investigate whether high-intensity focused ultrasound (HIFU) exposure is able to produce a fistula between the bladder and abdominal wall of a fetus with lower urinary tract obstruction (LUTO).

Materials and methods

We constructed a prototype HIFU transducer in combination with an imaging probe. HIFU was applied to the lower abdomen of a rabbit neonate that was complicated by LUTO as an experimental model to produce a fistula; HIFU was applied in a tank filled with degassed water. Exposed lesions were assessed by histological analysis at necropsy.

Results

When HIFU was applied at 5.5 kW/cm² of spatial-peak temporal average intensity (SPTA), a fistula was created between the lower abdominal wall and the urinary bladder; urine gushed out from the bladder through the fistula within 60 s after HIFU exposure.

Conclusion

The findings suggest that fetal diseases such as LUTO can be non-invasively treated using HIFU exposure from even outside the maternal body, though this study was performed in a water tank.     

Severe polyhydramnios in twin reversed arterial perfusion sequence: successful management with intrafetal alcohol ablation of acardiac twin and amniodrainage.

We present two cases of twin reversed arterial perfusion (TRAP) sequence complicated by severe polyhydramnios during the second trimester. Both cases were successfully managed at 27 and 26 weeks with ultrasound-guided intrafetal alcohol ablation of the acardiac twin and amniodrainage. The pump twins were delivered at 35 and 37 weeks, respectively, and both had uneventful postnatal courses. These cases suggest that, in the setting of severe polyhydramnios, prenatal intervention in TRAP sequence could certainly improve the otherwise poor prognosis of the pump twin. Targeting the main intra-abdominal vessel of the acardiac twin rather than its umbilical cord seems to be a good alternative in the prenatal treatment of these cases. The option of percutaneous intrafetal alcohol injection is widely available and less invasive, simpler and easier to perform than recently advocated endoscopic techniques.     

高强度聚焦超声用于消融治疗甲状腺良性结节研究进展

甲状腺结节多为良性结节,除外科手术切除之外,还可选择多种介入治疗方式,高强度聚焦超声(HIFU)为其中一种安全有效的消融治疗.本文就H1FU治疗甲状腺良性结节研究进展进行综述.     

肝癌患者体外高强度聚焦超声治疗的护理

通过对40例患体外采用高强度聚焦超声治疗肝癌的观察及护理，笔认为术前皮肤脱脂，脱气准备，术中体位固定，水温调控，术后皮肤护理并注意观察邻近组织器官有无损伤是减少并发症，确保治疗效果的关键。     

高强度聚焦超声体外辐照兔股动脉后的病理学观察

目的 探讨高强度聚焦超声(HIFU)体外辐照兔股动脉后血管的破坏情况。方法HIFU的工作频率为0．8MHz，焦距135mm，焦点平均强度为8000w／cm^2。30只兔随机分为三组，采用弹力纤维维多利亚蓝和丽春红S组织化学染色方法，观察HIFU辐照兔股动脉后即日、3d和7d的病理学变化。结果HIFU辐照后，各实验组均可见兔股动脉血管内皮细胞脱落、消失，管腔有微小血栓形成；平滑肌细胞出现核固缩，细胞排列紊乱；血管弹力纤维出现崩溃和断裂等现象。结论HIFU体外辐照可以造成兔股动脉血管损伤，并导致血流动力学改变。