Cai Youran, Cheng Zhongyuan, Yang Yuanting, Xu Baojun, Feng Qiwen, Liu Xu, Chen Jian, Zhou Qing
Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou, China.
Department of Radiology, the First Affiliated Hospital of Jinan University, Guangzhou, China.
Acta Neurol Belg. 2025 Feb;125(1):149-156. doi: 10.1007/s13760-024-02669-9. Epub 2024 Oct 30.
To compare thymic features using unenhanced computed tomography (CT) images between children with non-thymomatous ocular myasthenia gravis (OMG) and healthy children and determine the image feature cut-off values to allow differentiation of the two populations.
We conducted a retrospective study involving 66 children who underwent chest CT, with 33 having non-thymomatous OMG and 33 healthy children without any abnormality. We recorded CT features of the thymus in each child, including the mean CT attenuation value, thymus area, area ratio, anteroposterior (AP) length, width (W), thickness (T), and transverse diameter (TD). These characteristics were analyzed to distinguish OMG from healthy controls. The receiver operating characteristic (ROC) analysis was used to clarify the best assessment, and the optimal cut-off values were determined.
The mean CT attenuation value, the thymus area, area ratio, and TD were significantly different (P < 0.05) between the two groups. The mean CT attenuation value was the most significant characteristic in differentiating OMG and healthy controls (area under the curve [AUC] = 0.70). Using 50.41 as the cut-off value for mean CT attenuation, a specificity of 0.70 and sensitivity of 0.82 was observed for distinguishing the two groups (P = 0.003). Optimal differentiation was achieved by combining more than one characteristic including CT attenuation, thymus area, and TD with an optional area ratio (AUC = 0.72).
Non-enhanced CT of the thymus complemented the clinical workup of children with non-thymomatous OMG. The cut-off values of the CT features may allow robust differentiation of OMG children.
利用平扫计算机断层扫描（CT）图像比较非胸腺瘤性眼肌型重症肌无力（OMG）患儿与健康儿童的胸腺特征，并确定能够区分这两类人群的图像特征截断值。
我们进行了一项回顾性研究，纳入了66例接受胸部CT检查的儿童，其中33例为非胸腺瘤性OMG患儿，33例为无任何异常的健康儿童。我们记录了每个儿童胸腺的CT特征，包括平均CT衰减值、胸腺面积、面积比、前后径（AP）、宽度（W）、厚度（T）和横径（TD）。分析这些特征以区分OMG患儿与健康对照。采用受试者操作特征（ROC）分析来明确最佳评估方法，并确定最佳截断值。
两组之间的平均CT衰减值、胸腺面积、面积比和TD存在显著差异（P < 0.05）。平均CT衰减值是区分OMG患儿与健康对照的最显著特征（曲线下面积[AUC] = 0.70）。以50.41作为平均CT衰减的截断值，区分两组时观察到特异性为0.70，敏感性为0.82（P = 0.003）。通过结合包括CT衰减、胸腺面积和TD以及可选的面积比等多个特征可实现最佳区分（AUC = 0.72）。
胸腺的平扫CT补充了非胸腺瘤性OMG患儿的临床检查。CT特征的截断值可能有助于对OMG患儿进行可靠的区分。
