LaMasters D L, Watanabe T J, Chambers E F, Norman D, Newton T H
AJNR Am J Neuroradiol. 1982 Sep-Oct;3(5):485-94.
Definition of masses and malformations at the foramen magnum has been less than optimal with traditional radiographic techniques. The use of intrathecal metrizamide with computed tomographic (CT) scanning improves contrast resolution and facilitates detection of abnormalities that may not be apparent on Pantopaque cisternography, plain films, or conventional axial CT alone. Fifty patients with clinically suspected foramen-magnum lesions were evaluated with this technique. Forty were abnormal with the following findings: 14 cases of the Chiari malformation (five cases had associated syringomyelia), five meningiomas, three neuromas, a chondrosarcoma, a chordoma, and five cervical and three brainstem gliomas. Six cases of syringomyelia, a large posterior-fossa subarachnoid cyst, and an anomaly of the cisterna magna were also diagnosed. Sagittal and coronal images were beneficial in defining tonsillar position, configuration of the fourth ventricle, and the relations of mass lesions to the spinal canal and subarachnoid space. Metrizamide CT cisternography provides superior spatial and contrast resolution of lesions at the foramen magnum not obtainable with other radiographic techniques. Morbidity is minimal because of the low dose of metrizamide used. Multiplanar reformations are particularly helpful in assessing anatomic detail not readily recognized on axial scans alone.
使用传统的放射学技术对枕大孔区的肿块和畸形进行诊断，效果一直不太理想。鞘内注射甲泛葡胺并结合计算机断层扫描（CT），可提高对比度分辨率，有助于发现单独使用碘苯酯脑池造影、平片或传统轴向CT可能无法显示的异常情况。采用该技术对50例临床怀疑枕大孔区病变的患者进行了评估。其中40例存在异常，具体表现如下：14例Chiari畸形（5例合并脊髓空洞症）、5例脑膜瘤、3例神经瘤、1例软骨肉瘤、1例脊索瘤，以及5例颈段和3例脑干胶质瘤。还诊断出6例脊髓空洞症、1例巨大后颅窝蛛网膜下囊肿和1例小脑延髓池异常。矢状位和冠状位图像有助于明确扁桃体位置、第四脑室形态，以及肿块病变与椎管和蛛网膜下腔的关系。甲泛葡胺CT脑池造影对枕大孔区病变具有其他放射学技术无法达到的卓越空间和对比度分辨率。由于甲泛葡胺用量低，其所致发病率极低。多平面重建对于评估仅通过轴向扫描难以识别的解剖细节特别有帮助。
