Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA.
Department of Diagnostic Imaging and Radiology, Children's National Hospital, Washington, DC, USA.
Pediatr Radiol. 2020 May;50(6):840-847. doi: 10.1007/s00247-020-04629-w. Epub 2020 Feb 14.
The adrenal gland plays a vital role in fetal growth. Many disease states such as congenital adrenal hyperplasia, hemorrhage and tumors can lead to morphological changes in the gland. Ultrasound measurements of normal adrenal sizes in the fetus reported in the literature have shown a trend of increasing size with gestational age. There is no literature available on standard fetal adrenal sizes or detailed appearance by fetal MRI.
The purpose of this study was to provide MR data on the size and signal characteristics of the fetal adrenal gland throughout the second and third trimesters.
In this retrospective review, we selected 185 prenatal MRIs obtained from Jan. 1, 2014, to May 31, 2017, with normal abdominal findings for inclusion. The adrenal glands were identified in coronal, sagittal or axial T2-W planes and coronal T1-W plane when available. We measured the length and thickness of the medial and lateral limbs of the right and left adrenal glands and recorded signal intensity on T1-W and T2-W sequences, gender and gestational age in each case.
The gestational age (GA) ranged 18-37 weeks. Visibility of the adrenal glands on T2-W images was high (90.3-97.2%) up to 30 weeks of GA but declined afterward (47.5-62.2% at 31-37 weeks). Visibility on T1-W images increased with GA, ranging from 21.4% visibility at 18-22 weeks and increasing to 40% at 35-37 weeks. Mean lengths of the adrenal gland limbs steadily increased from 8.2 mm at 18-22 weeks to 11.0 mm at 35-37 weeks. In the second trimester, adrenal glands were low in signal intensity on T2-W images and were surrounded by hyperintense perirenal fatty tissue. In the third trimester, the glands became less distinct, with increasing signal and obliteration of perirenal tissue. The glands were moderately hyperintense on T1-W images throughout pregnancy, with increasing visibility as pregnancy progressed.
Normal sizes and signal intensities for adrenal glands are reported. Visibility of adrenal glands on T2-W images was 90.3-97.2% up to 30 weeks but declined thereafter. Visibility on T1-W images increased in the third trimester. Adrenal gland sizes increased with gestational age.
肾上腺在胎儿生长中起着至关重要的作用。许多疾病状态，如先天性肾上腺增生、出血和肿瘤，可导致腺体形态发生变化。文献中报道的胎儿正常肾上腺大小的超声测量显示出随胎龄增加而增大的趋势。目前尚无关于胎儿标准肾上腺大小或胎儿 MRI 详细外观的文献。
本研究旨在提供胎儿第二和第三个三个月期间肾上腺大小和信号特征的 MRI 数据。
在这项回顾性研究中，我们选择了 2014 年 1 月 1 日至 2017 年 5 月 31 日期间的 185 例正常腹部产前 MRI 进行纳入分析。在冠状、矢状或轴位 T2-W 平面以及有条件时的冠状 T1-W 平面识别肾上腺。我们测量了右侧和左侧肾上腺的内、外侧肢的长度和厚度，并记录了每个病例的 T1-W 和 T2-W 序列上的信号强度、性别和胎龄。
胎龄（GA）范围为 18-37 周。在 GA 达 30 周之前，T2-W 图像上肾上腺的可见度较高（90.3-97.2%），但此后则下降（31-37 周时为 47.5-62.2%）。T1-W 图像上的可见度随 GA 增加而增加，范围从 18-22 周时的 21.4%可见度增加到 35-37 周时的 40%。肾上腺肢的平均长度从 18-22 周的 8.2mm 稳步增加到 35-37 周的 11.0mm。在第二个三个月中，肾上腺在 T2-W 图像上的信号强度较低，周围环绕着高信号的肾周脂肪组织。在第三个三个月中，腺体变得不那么明显，信号增加，肾周组织消失。在整个妊娠期间，肾上腺在 T1-W 图像上呈中度高信号，随着妊娠的进展，可见度增加。
报告了正常的肾上腺大小和信号强度。T2-W 图像上肾上腺的可见度在 30 周之前为 90.3-97.2%，但此后则下降。T1-W 图像上的可见度在第三个三个月中增加。肾上腺大小随胎龄增加而增加。
