Department of Radiological Sciences, Umberto I Hospital, Sapienza University of Rome, Rome, Italy.
Prenat Diagn. 2010 Dec;30(12-13):1178-84. doi: 10.1002/pd.2641.
To establish if a correlation exists between apparent diffusion coefficient (ADC) values, obtained by diffusion-weighted imaging (DWI), and placental aging.
The study is divided into a retrospective phase and a prospective one.In the first phase, 145 pregnant women underwent fetal magnetic resonance imaging (MRI) for suspected disorders in several organs. We performed DWI (b value 0, 200 and 700 s/mm(2)) in all the fetuses, evaluating the patients in whom the whole placenta was visible.In the prospective phase, 50 women (52 fetuses) underwent MRI. We performed, in the same patient, two echo-planar sequences with b values of 0, 200 and 700, and 50, 200 and 700 s/mm(2), including the whole placenta.The ADC maps were calculated for all fetuses, divided into three groups based on gestational age (GA): group I: 20-26 weeks' gestation, II: 27-33, III: 34-40.
In the retrospective phase, ADC values had a range from 1 to 2.4 mm(2)/s, showing a significant correlation between ADC values and GA.ADC values obtained by DWI with b value 0, 200 and 700 s/mm(2) had a range from 0.8 to 2.5 mm(2)/s, with an inverse correlation between ADC values and GA, whereas the ADC values with b value 50, 200 and 700 s/mm(2) did not show any statistical correlation (range: 1.5-1.7 mm(2)/s).
DWI with ADC maps can not be considered markers for placental aging because they are affected by perfusional and circulatory motion.
确定通过弥散加权成像（DWI）获得的表观扩散系数（ADC）值与胎盘老化之间是否存在相关性。
该研究分为回顾性阶段和前瞻性阶段。在第一阶段，145 名孕妇因怀疑多个器官存在异常而接受胎儿磁共振成像（MRI）检查。我们对所有胎儿进行了 DWI（b 值为 0、200 和 700 s/mm(2)），评估了能够看到整个胎盘的患者。在前瞻性阶段，50 名女性（52 名胎儿）接受了 MRI 检查。我们在同一名患者中同时进行了两个回波平面序列，b 值分别为 0、200 和 700，以及 50、200 和 700 s/mm(2)，包括整个胎盘。对所有胎儿计算 ADC 图，并根据胎龄（GA）分为三组：I 组：20-26 周；II 组：27-33 周；III 组：34-40 周。
在回顾性阶段，ADC 值的范围为 1 至 2.4 mm(2)/s，ADC 值与 GA 之间存在显著相关性。b 值为 0、200 和 700 s/mm(2)的 DWI 获得的 ADC 值范围为 0.8 至 2.5 mm(2)/s，与 GA 呈负相关，而 b 值为 50、200 和 700 s/mm(2)的 ADC 值没有显示出任何统计学相关性（范围：1.5-1.7 mm(2)/s）。
DWI 与 ADC 图不能作为胎盘老化的标志物，因为它们受灌注和循环运动的影响。
