Chen Wenhao, Zhang Hui, Zhang Wenyi, Su Meng, Xie Raoying, Li Kejie, Xia Xiaofang, Zou Changlin
Department of Chemoradiotherapy Oncology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
J Med Imaging Radiat Oncol. 2019 Oct;63(5):657-664. doi: 10.1111/1754-9485.12903. Epub 2019 Jun 7.
Sparing of the organs at risk (OARs) is a crucial task in daily radiotherapy practice. Irradiation of the optic chiasm (OC) results in radiation-induced optic neuropathy (RION). The structure of the OC is complex, and OC morphology can vary in axial images. Therefore, a standard atlas can result in inaccurate descriptions of OC morphology in different patients. The aim of our study was to provide a guide based on computed tomography (CT) for the delineation of different types of OC.
Thirty-six patients were selected to participate in our study. These patients underwent CT analysis of the brain, head and neck regions in a supine position. Axial images 3 mm in thickness were obtained at 3-mm intervals. A magnetic resonance imaging (MRI) study was also performed using the same set-up. The OC was then delineated. The contours were revised by three neuroradiologists and nine radiation oncologists with > 5 years of expertise.
Three types of OC were distinguished by magnetic resonance (MR). The location and boundaries of normal, prefixed and postfixed chiasms were developed with a CT-based atlas. Discrepancies were observed in the delineation of the prefixed and postfixed OC.
Our guide allows improved definitions of the anatomical boundaries for different types of OC. Our experience could provide useful information for radiation oncologists in daily practice.
在日常放射治疗实践中，保护危及器官（OARs）是一项至关重要的任务。对视交叉（OC）进行照射会导致放射性视神经病变（RION）。OC的结构复杂，其形态在轴向图像中可能有所不同。因此，标准图谱可能会导致对不同患者OC形态的描述不准确。我们研究的目的是提供一份基于计算机断层扫描（CT）的指南，用于描绘不同类型的OC。
选择36例患者参与我们的研究。这些患者仰卧位接受脑部、头部和颈部区域的CT分析。以3毫米的间隔获取厚度为3毫米的轴向图像。还使用相同的设置进行了磁共振成像（MRI）研究。然后勾勒出OC。轮廓由三位神经放射科医生和九位具有超过5年专业经验的放射肿瘤学家进行修订。
通过磁共振（MR）区分出三种类型的OC。利用基于CT的图谱确定了正常、前置和后置视交叉的位置和边界。在前置和后置OC的描绘中观察到差异。
我们的指南有助于更好地定义不同类型OC的解剖边界。我们的经验可为放射肿瘤学家在日常实践中提供有用信息。
