应用扩散张量成像的定量胎儿 MRI 在“短”胼胝体病例中的应用。

URP FETUS 7328 and LUMIERE Platform, University of Paris, Paris, France.

Department of Obstetrics, Fetal Medicine and Surgery, Necker-Enfants Malades Hospital, APHP, Paris, France.

Ultrasound Obstet Gynecol. 2024 Mar;63(3):385-391. doi: 10.1002/uog.27473. Epub 2024 Feb 7.

OBJECTIVES

It has been suggested previously that the presence of Probst bundles (PB) in cases with a short corpus callosum (SCC) on diffusion tensor imaging (DTI) may help to differentiate between corpus callosal (CC) dysplasia and a variant of normal CC development. The objectives of this study were to compare DTI parameters between cases of SCC vs normal CC and between cases of SCC with PB (SCC-PB+) vs SCC without PB (SCC-PB-).

METHODS

This was a retrospective study of patients referred to the Necker Hospital in Paris, France, for magnetic resonance imaging (MRI) evaluation of an apparently isolated SCC detected by sonography between November 2016 and December 2022 (IRB: 00011928). MRI was performed using a 1.5-Tesla Signa system. T2-weighted axial and sagittal sequences of the fetal brain were used to measure the length and thickness of the CC. 16-direction DTI axial brain sequences were performed to identify the presence of PB and to generate quantitative imaging parameters (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)) of the entire CC, genu, body and splenium. Cases in which other associated brain abnormalities were detected on MRI were excluded. Cases were matched for fetal gender and gestational age with controls in a 1:3 ratio. Control cases were normal fetuses included in the LUMIERE on the FETUS trial (NCT04142606) that underwent the same DTI evaluation of the brain. Comparisons between SCC and normal CC cases, and between SCC-PB+ and SCC-PB- cases were performed using ANOVA and adjusted for potential confounders using ANCOVA.

RESULTS

Twenty-two SCC cases were included and compared with 66 fetuses with a normal CC. In 10/22 (45.5%) cases of SCC, PB were identified. As expected, dimensions of the CC were significantly smaller in SCC compared with normal CC cases (all P < 0.01). In SCC-PB+ vs SCC-PB- cases, FA values were significantly lower in the entire CC (median, 0.21 (range, 0.19-0.24) vs 0.24 (range, 0.22-0.28); P < 0.01), genu (median, 0.21 (range, 0.15-0.29) vs 0.24 (range, 0.17-0.29); P = 0.04), body (median, 0.21 (range, 0.18-0.23) vs 0.23 (range, 0.21-0.27); P = 0.04) and splenium (median, 0.22 (range, 0.16-0.30) vs 0.25 (range, 0.20-0.29); P = 0.03). ADC values were significantly higher in the entire CC, genu and body in SCC-PB+ vs SCC-PB- cases (all P < 0.05). In SCC-PB+ cases, all FA values were significantly lower, and ADC values in the CC body were significantly higher compared with normal CC cases (all P < 0.05). In SCC-PB- cases, there was no significant difference in FA and ADC compared with normal CC cases (all P > 0.05).

CONCLUSIONS

Fetal DTI evaluation of the CC showed that FA values were significantly lower and ADC values tended to be significantly higher in SCC-PB+ compared with normal CC cases. This may highlight alterations of the white matter microstructure in SCC-PB+. In contrast, isolated SCC-PB- did not demonstrate significant changes in DTI parameters, strengthening the possibility that this is a normal CC variant. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

目的

先前有研究表明，在弥散张量成像（DTI）上存在胼胝体短缩（SCC）的病例中存在 Probst 束（PB）可能有助于区分胼胝体（CC）发育不良和正常 CC 发育的变异。本研究的目的是比较 SCC 与正常 CC 之间以及 SCC 伴 PB（SCC-PB+）与 SCC 无 PB（SCC-PB-）之间的 DTI 参数。

方法

这是一项回顾性研究，纳入了 2016 年 11 月至 2022 年 12 月期间因超声检查发现的疑似孤立 SCC 而在法国巴黎 Necker 医院接受磁共振成像（MRI）评估的患者（IRB：00011928）。MRI 使用 1.5-Tesla Signa 系统进行。胎儿脑的 T2 加权轴位和矢状位序列用于测量 CC 的长度和厚度。进行 16 方向弥散张量成像轴位脑序列以识别 PB 的存在并生成整个 CC、膝部、体部和压部的定量成像参数（各向异性分数（FA）和表观扩散系数（ADC））。排除了 MRI 上发现其他相关脑异常的病例。病例按照胎儿性别和胎龄与对照组以 1:3 的比例匹配。对照组为正常胎儿，纳入 FETUS 试验（NCT04142606）的 LUMIERE 部分，接受了相同的脑 DTI 评估。使用方差分析比较 SCC 与正常 CC 病例，以及 SCC-PB+与 SCC-PB-病例之间的差异，并使用协方差分析调整潜在混杂因素。

结果

纳入了 22 例 SCC 病例，并与 66 例正常 CC 胎儿进行了比较。在 22 例 SCC 病例中，有 10 例（45.5%）发现了 PB。正如预期的那样，SCC 病例的 CC 尺寸明显小于正常 CC 病例（均 P<0.01）。在 SCC-PB+与 SCC-PB-病例中，整个 CC（中位数，0.21（范围，0.19-0.24）比 0.24（范围，0.22-0.28）；P<0.01）、膝部（中位数，0.21（范围，0.15-0.29）比 0.24（范围，0.17-0.29）；P=0.04）、体部（中位数，0.21（范围，0.18-0.23）比 0.23（范围，0.21-0.27）；P=0.04）和压部（中位数，0.22（范围，0.16-0.30）比 0.25（范围，0.20-0.29）；P=0.03）的 FA 值明显较低。SCC-PB+病例的整个 CC、膝部和体部的 ADC 值明显较高（均 P<0.05）。在 SCC-PB+病例中，所有 FA 值均明显较低，而 CC 体部的 ADC 值明显较高，与正常 CC 病例相比（均 P<0.05）。在 SCC-PB-病例中，FA 和 ADC 与正常 CC 病例相比无显著差异（均 P>0.05）。