PURPOSE Peripheral enhancement characteristics on magnetic resonance imaging (MRI), namely the rim and flame signs, are specific for intramedullary spinal cord metastases (ISCM) compared to primary cord masses. The study compared the frequency of a novel finding-the central dot sign-in ISCMs versus primary intramedullary masses. METHODS In this study 45 patients with 64 ISCMs and 64 control patients with 64 primary intramedullary cord masses were investigated and 2 radiologists blinded to lesion type independently evaluated MR images for the presence of a central dot sign: a punctate focus of enhancement in/near the center of an enhancing intramedullary mass. The frequency of this sign in the two patient groups was compared. RESULTS A total of 63 enhancing ISCMs in 44 patients and 54 enhancing primary cord masses in 54 patients were included. The central dot sign was identified in 6% (4/63) of enhancing ISCMs in 9% (4/44) of patients and in none (0/54) of the enhancing primary cord masses (p = 0.038, per patient). The specificity for diagnosing ISCMs among spinal cord masses was 100%. The central dot sign was present in the axial plane only in two ISCMs and in the axial and sagittal planes in two ISCMs. The two ISCMs harboring the central dot sign also demonstrated both the previously described rim and flame signs, and two also demonstrated the rim sign alone. CONCLUSION The central dot sign is not sensitive but highly specific for ISCMs compared to primary spinal cord masses. The rim and/or flame signs may or may not be concurrently present in ISCMs.

中文翻译：

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中心点征：髓内脊髓转移的特定钆后增强特征。

目的 与原发性脊髓肿块相比，磁共振成像 (MRI) 的外周增强特征，即边缘和火焰征，对于髓内脊髓转移瘤 (ISCM) 具有特异性。该研究比较了新发现的频率 - 中心点登录 ISCM 与原发性髓内肿块。方法 在这项研究中，对 45 名具有 64 个 ISCM 的患者和 64 名具有 64 个原发性髓内脊髓肿块的对照患者进行了调查，并且 2 位对病变类型不了解的放射科医师独立评估了 MR 图像是否存在中心点征：点状强化在/附近增强髓内肿块的中心。比较了两个患者组中这种迹象的频率。结果 共包括 44 名患者中的 63 个增强型 ISCM 和 54 名患者中的 54 个增强型原发性脊髓肿块。在 9% (4/44) 的患者中，在 6% (4/63) 的增强 ISCM 中发现了中心点征，而在增强的原发性脊髓肿块中没有 (0/54)（p = 0.038，每位患者）。在脊髓肿块中诊断 ISCM 的特异性为 100%。中心点符号仅出现在两个 ISCM 的轴向平面中，以及两个 ISCM 的轴向和矢状平面中。带有中心点标志的两个 ISCM 也展示了前面描述的边缘和火焰标志，另外两个还单独展示了边缘标志。结论与原发性脊髓肿块相比，中央点符号对 ISCM 不敏感但具有高度特异性。边缘和/或火焰标志可能会或可能不会同时出现在 ISCM 中。