Comparison of 2D and 3D oxygen-enhanced MRI of the placenta.

Twelve subjects were recruited from St Mary’s Hospital, Manchester, following written informed consent (ethical approval REC:14/NW/0195 and 19/NW/0177) between 1st January 2018 to 31st December 2019.Subjects were scanned using a 1.5T Philips Achieva MRI scanner (Philips Medical Systems Best, NL) whilst supine with a left lateral tilt, to reduce aortocaval compression by the gravid uterus. A cardiac receiver coil was placed on the abdomen, covering the entire uterus. Non-rebreathing masks (Intersurgical, Wokingham, UK) delivered medical air or 100% oxygen at a flow rate of 15 L/min to the subjects and respiratory triggering was used to minimise motion from maternal breathing.T2-weighted structural scans were used to determine the position of the placenta and plan the oxygen-enhanced MRI (OE-MRI) slices. Two inversion recovery OE-MRI protocols were performed: a 3D turbo-spin echo with half Fourier acquisition (3D-HASTE) for full placental coverage and a 2D turbo-spin echo (2D-TSE), as used in previous studies. The single 2D slice positioned perpendicular to the placenta at the level of the cord insertion. The orientation of the 3D-HASTE matched that of the 2D-TSE. For both OE-MRI protocols a T1 map was calculated using a set of inversion recovery images, followed by a dynamic series of T1-weighted images during which the gas supply to the subject is switched from medical air (21%) to 100% oxygen in order to determine deltaR1.To request access to data please email: [e-mail]

自2018年1月1日至2019年12月31日期间，在曼彻斯特圣玛丽医院招募了十二名受试者，并在获得书面知情同意（伦理审查批准号：REC:14/NW/0195和19/NW/0177）后进行招募。受试者在左侧倾斜卧位下使用1.5T飞利浦Achieva MRI扫描仪（飞利浦医疗系统，荷兰Best）进行扫描，以减轻怀孕子宫对主动脉和下腔静脉的压迫。在腹部放置了心脏接收线圈，覆盖整个子宫。使用非重复呼吸面罩（Intersurgical，英国Wokingham）以15 L/min的流速向受试者输送医疗空气或100%氧气，并采用呼吸触发技术以最小化母体呼吸引起的运动。利用T2加权结构扫描确定胎盘位置并规划氧气增强MRI（OE-MRI）切片。执行了两种反转恢复OE-MRI方案：一种是用于全面胎盘覆盖的3D半傅里叶采集快速自旋回波（3D-HASTE），另一种是用于之前研究中使用的2D快速自旋回波（2D-TSE）。单个2D切片垂直于胎盘，位于脐带插入水平。3D-HASTE的方位与2D-TSE相匹配。对于两种OE-MRI方案，通过一系列反转恢复图像计算T1图，随后进行动态T1加权图像系列，在此期间将受试者的气体供应从21%的医疗空气切换至100%氧气，以确定deltaR1。如需获取数据访问权限，请通过电子邮件[e-mail]联系。