Denbow M L, Rivens I H, Rowland I J, Leach M O, Fisk N M, ter Haar G R
Centre for Fetal Care, Institute of Obstetrics and Gynaecology, Imperial College School of Medicine, Queen Charlotte's and Chelsea Hospital, London, United Kingdom.
Am J Obstet Gynecol. 2000 Feb;182(2):387-92. doi: 10.1016/s0002-9378(00)70229-8.
This study was undertaken to investigate the ability of focused ultrasonic surgery to occlude blood flow in vivo.
A 5-mm linear track exposure of 1.7-MHz focused ultrasound was applied across the femoral vessels for 5 seconds. Free field spatial peak intensities in the range of 1,000 to 4,660 W x cm(-2) were used. Vascular occlusion was confirmed after demonstration of an absent distal arterial pulse and an absent flow signal on magnetic resonance angiography and subtracted (after minus before) contrast-enhanced dual-echo steady-state sequences.
The minimum intensity for consistent vascular occlusion was 1,690 W x cm(-2) at a focal depth of 5 mm when the transducer was moved at 1 mm x s(-1) orthogonal to the direction of blood flow.
This study demonstrates that focused ultrasonic surgery can achieve reproducible vascular occlusion in vivo. Potential obstetric applications include noninvasive ultrasonographically guided occlusion of placental vessels mediating interfetal transfusion in monochorionic twins.
本研究旨在探讨聚焦超声手术在体内阻断血流的能力。
将1.7兆赫兹的聚焦超声以5毫米线性轨迹照射股血管5秒。使用的自由场空间峰值强度范围为1000至4660瓦×厘米⁻²。在证实远端动脉搏动消失以及磁共振血管造影和减影（减后减前）对比增强双回波稳态序列上血流信号消失后，确认血管闭塞。
当换能器以1毫米×秒⁻¹的速度垂直于血流方向移动时，在5毫米焦深处实现一致血管闭塞的最小强度为1690瓦×厘米⁻²。
本研究表明聚焦超声手术可在体内实现可重复的血管闭塞。潜在的产科应用包括在单绒毛膜双胎中介导胎儿间输血的胎盘血管的无创超声引导闭塞。
