表观扩散系数与大分子质子分数的直接比较作为人类胎儿大脑成熟的定量生物标志物。
Direct comparison between apparent diffusion coefficient and macromolecular proton fraction as quantitative biomarkers of the human fetal brain maturation.
机构信息
Institute "International Tomography Center" of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation.
University of Washington, Department of Radiology, Seattle, Washington, USA.
出版信息
J Magn Reson Imaging. 2019 Jul;50(1):52-61. doi: 10.1002/jmri.26635. Epub 2019 Jan 11.
BACKGROUND
Apparent diffusion coefficient (ADC) is known as a quantitative biomarker of prenatal brain maturation. Fast macromolecular proton fraction (MPF) mapping is an emerging method for quantitative assessment of myelination that was recently adapted to fetal MRI.
PURPOSE
To compare the capability of ADC and MPF to quantify the normal fetal brain development.
STUDY TYPE
Prospective.
POPULATION
Forty-two human fetuses in utero (gestational age [GA] = 27.7 ± 6.0, range 20-38 weeks).
FIELD STRENGTH/SEQUENCE: 1.5 T; diffusion-weighted single-shot echo-planar spin-echo with five b-values for ADC mapping; spoiled multishot echo-planar gradient-echo with T , proton density, and magnetization transfer contrast weightings for single-point MPF mapping.
ASSESSMENT
Two operators measured ADC and MPF in the medulla, pons, cerebellum, thalamus, and frontal, occipital, and temporal cerebral white matter (WM).
STATISTICAL TESTS
Mixed repeated-measures analysis of variance (ANOVA) with the factors of pregnancy trimester and brain structure; Pearson correlation coefficient (r); Hotelling-Williams test to compare strengths of correlations.
RESULTS
From the 2 to 3 trimester, ADC significantly decreased in the thalamus and cerebellum (P < 0.005). MPF significantly increased in the medulla, pons, thalamus, and cerebellum (P < 0.005). Cerebral WM had significantly higher ADC and lower MPF compared with the medulla and pons in both trimesters. MPF (r range 0.83, 0.89, P < 0.001) and ADC (r range -0.43, -0.75, P ≤ 0.004) significantly correlated with GA and each other (r range -0.32, -0.60, P ≤ 0.04) in the medulla, pons, thalamus, and cerebellum. No significant correlations or distinctions between regions and trimesters were observed for cerebral WM (P range 0.1-0.75). Correlations with GA were significantly stronger for MPF compared with ADC in the medulla, pons, and cerebellum (Hotelling-Williams test, P < 0.003) and similar in the thalamus. Structure-averaged MPF and ADC values strongly correlated (r = 0.95, P < 0.001).
DATA CONCLUSION
MPF and ADC demonstrated qualitatively similar but quantitatively different spatiotemporal patterns. MPF appeared more sensitive to changes in the brain structures with prenatal onset of myelination.
LEVEL OF EVIDENCE
2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;50:52-61.
背景
表观扩散系数（ADC）是产前脑成熟的定量生物标志物。快速大分子质子分数（MPF）图是一种新兴的髓鞘定量评估方法，最近已被应用于胎儿 MRI。
目的
比较 ADC 和 MPF 定量评估正常胎儿脑发育的能力。
研究类型
前瞻性。
人群
42 例宫内胎儿（胎龄[GA] = 27.7 ± 6.0，范围 20-38 周）。
磁场强度/序列：1.5 T；用于 ADC 映射的扩散加权单次激发回波平面自旋回波，具有 5 个 b 值；用于单点 MPF 映射的扰动脉冲多回波平面梯度回波，具有 T 1、质子密度和磁化传递对比权重。
评估
两名操作人员在延髓、脑桥、小脑、丘脑和额叶、枕叶和颞叶脑白质（WM）中测量 ADC 和 MPF。
统计学检验
采用妊娠三阶段和脑结构的混合重复测量方差分析（ANOVA）；Pearson 相关系数（r）；Hotelling-Williams 检验比较相关性的强度。
结果
从 2 到 3 个孕期，丘脑和小脑的 ADC 显著降低（P < 0.005）。延髓、脑桥、丘脑和小脑的 MPF 显著增加（P < 0.005）。与脑桥和延髓相比，大脑 WM 在两个孕期均具有更高的 ADC 和更低的 MPF。MPF（r 范围 0.83、0.89，P < 0.001）和 ADC（r 范围-0.43、-0.75，P ≤ 0.004）与 GA 之间以及彼此之间（r 范围-0.32、-0.60，P ≤ 0.04）均与 GA 呈显著相关，在延髓、脑桥、丘脑和小脑。大脑 WM 未见区域和孕期之间存在显著相关性或差异（P 范围 0.1-0.75）。与 ADC 相比，MPF 与 GA 的相关性在延髓、脑桥和小脑（Hotelling-Williams 检验，P < 0.003）更强，而在丘脑则相似。脑结构平均 MPF 和 ADC 值具有很强的相关性（r = 0.95，P < 0.001）。
数据结论
MPF 和 ADC 表现出定性相似但定量不同的时空模式。MPF 似乎对具有产前髓鞘形成的脑结构变化更敏感。
证据水平
2 技术功效阶段：2 J. Magn. Reson. Imaging 2019；50：52-61。
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