Background

To identify preterm infants at risk for neurodevelopment impairment that might benefit from early neurorehabilitation, early prognostic biomarkers of future outcomes are needed.

Objective

To determine whether synthetic MRI is sensitive to age-related changes in regional tissue relaxation times in the brain of preterm born neonates when scanned at term equivalent age (TEA, 37–42 weeks), and to investigate whether severe postnatal morbidity results in prolonged regional tissue relaxation times.

Materials and methods

This retrospective study included 70 very preterm born infants scanned with conventional and synthetic MRI between January 2017 and June 2019 at TEA. Infants with severe postnatal morbidity were allocated to a high-risk group (n = 22). All other neonates were allocated to a low-risk group (n = 48). Linear regression analysis was performed to determine the relationship between relaxation times and postmenstrual age (PMA) at scan. Analysis of covariance was used to evaluate the impact of severe postnatal morbidity in the high-risk group on T1 and T2 relaxation times. Receiver operating characteristic (ROC) curves were plotted and analysed with area under the ROC curve (AUC) to evaluate the accuracy of classifying high-risk patients based on regional relaxation times.

Results

A linear age-related decrease of T1 and T2 relaxation times correlating with PMA at scan (between 37 and 42 weeks) was found in the deep gray matter, the cerebellum, the cortex, and the posterior limb of the internal capsule (PLIC) (p < .005 each), but not in the global, frontal, parietal, or central white matter. Analysis of covariance for both risk groups, adjusted for PMA, revealed significantly prolonged regional tissue relaxation times in neonates with severe postnatal morbidity, which was best illustrated in the central white matter of the centrum semiovale (T1 Δ = 11.5%, T2 Δ = 13.4%, p < .001) and in the PLIC (T1 Δ = 9.2%, T2 Δ = 6.9%, p < .001). The relaxation times in the PLIC and the central white matter predicted high-risk status with excellent accuracy (AUC range 0.82–0.86).

Conclusion

Synthetic MRI-based relaxometry in the brain of preterm born neonates is sensitive to age-related maturational changes close to TEA. Severe postnatal morbidity correlated with a significant delay in tissue relaxation. Synthetic MRI may provide early prognostic biomarkers for neurodevelopment impairment.

中文翻译：

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合成核磁共振成像显示早产儿出生后严重发病的新生儿脑部区域弛豫时间延长

背景

为了识别可能受益于早期神经康复的神经发育受损风险的早产儿，需要早期预后的生物标志物来预测未来的结局。

目的

确定当在足月同等年龄（TEA，37-42周）进行扫描时，合成MRI是否对早产新生儿大脑中区域性组织松弛时间的年龄相关变化敏感，并调查严重的产后发病是否会导致区域性延长组织松弛时间。

材料和方法

这项回顾性研究纳入了2017年1月至2019年6月在TEA接受常规和合成MRI扫描的70名早产婴儿。出生后发病严重的婴儿被分为高危组（n = 22）。所有其他新生儿均被分配到低风险组（n = 48）。进行线性回归分析以确定扫描时放松时间与月经后年龄（PMA）之间的关系。使用协方差分析来评估高危组中严重的产后发病对T1和T2放松时间的影响。绘制受试者工作特征（ROC）曲线，并在ROC曲线（AUC）下进行面积分析，以评估基于区域放松时间对高危患者进行分类的准确性。

结果

在内囊（PLIC）的深灰质，小脑，皮质和后肢中发现，与年龄相关的与TMA相关的T1和T2松弛时间的线性下降与扫描时PMA相关（在37至42周之间）（ p <.005），但不在整体，额叶，顶叶或中央白质中。校正了PMA的两个风险组的协方差分析表明，患有严重产后发病的新生儿的区域组织舒张时间显着延长，这在中心半卵白质中央白质中得到最好的说明（T1Δ= 11.5％，T2Δ= 13.4 ％，p <.001）和PLIC（T1Δ= 9.2％，T2Δ= 6.9％，p <.001）。在PLIC和中央白质中的弛豫时间可预测具有高准确性的高风险状态（AUC范围为0.82-0.86）。

结论

早产新生儿大脑中基于MRI的合成弛豫法对接近TEA的与年龄相关的成熟变化敏感。严重的产后发病与组织松弛明显延迟有关。合成MRI可能为神经发育受损提供早期预后生物标志物。