Cartry C, Viallon V, Hornoy P, Adamsbaum C
Service d'Imagerie Pédiatrique, Hôpital St-Vincent-de-Paul, AP-HP, 82, avenue Denfert Rochereau, 75674 Paris cedex 14.
J Radiol. 2010 May;91(5 Pt 1):561-6. doi: 10.1016/s0221-0363(10)70088-3.
To determine the reliability and variations of apparent diffusion coefficient (ADC) values in normal fetuses. Materials and methods. Retrospective study (2007-2008) on 22 normal fetal MR examinations, performed between 30 and 34 of gestation, using a routine protocol (T1W and T2W images in 3 planes, b=1,000 diffusion-weighted imaging) without sedation. ADC values were measured by placing 3 adjacent regions of interest (ROI) including a centrally located ROI over the right frontal and occipital white matter (6 ROI).
reproducibility of adjacent ADC values (intraclass correlation coefficient: ICC) and comparison between frontal and occipital ADC values (Wilcoxon).
The mean ADC value was 1.78 mm(2)/s for the frontal white matter (+ or - 0.10) and 1.66 mm(2)/s for the occipital white matter (+ or - 0.12) with excellent reproducibility (ICC=0.91 in the frontal lobe) and good reproducibility for adjacent measurements (ICC=0.7). A linear inverse correlation existed between ADC values and gestational age in the occipital lobes, and a significant fronto-occipital gradient existed after 32 weeks of gestational age.
ADC value measurements are reliable and inversely correlated with gestational age due to fetal brain maturation. The existence of a fronto-occipital gradient after 32 weeks of gestational age could be a marker of normal maturation used in clinical practice.
确定正常胎儿表观扩散系数（ADC）值的可靠性及变化情况。材料与方法。对2007年至2008年间22例正常胎儿磁共振检查进行回顾性研究，这些检查在妊娠30至34周时进行，采用常规方案（三个平面的T1加权和T2加权图像，b = 1000的扩散加权成像），未使用镇静剂。通过放置3个相邻的感兴趣区（ROI）来测量ADC值，其中包括位于右侧额叶和枕叶白质中央的一个ROI（共6个ROI）。
相邻ADC值的可重复性（组内相关系数：ICC）以及额叶和枕叶ADC值之间的比较（Wilcoxon检验）。
额叶白质的平均ADC值为1.78 mm²/s（±0.10），枕叶白质的平均ADC值为1.66 mm²/s（±0.12），具有出色的可重复性（额叶ICC = 0.91）以及相邻测量的良好可重复性（ICC = 0.7）。枕叶ADC值与胎龄之间存在线性负相关，孕32周后存在显著的额枕梯度。
由于胎儿脑成熟，ADC值测量是可靠的且与胎龄呈负相关。孕32周后额枕梯度的存在可能是临床实践中正常成熟的一个标志。
