Madhavan Ajay A, Diehn Felix E, Rykken Jeffrey B, Wald John T, Wood Chris P, Schwartz Kara M, Kaufmann Timothy J, Hunt Christopher H, Kim Dong Kun, Eckel Laurence J
Division of Neuroradiology, Department of Radiology, Mayo Clinic, 200 First St SW, MN 55905, Rochester, USA.
Division of Neuroradiology, Department of Radiology, University of Minnesota, 420 Delaware St SE, MN 55455, Minneapolis, USA.
Clin Neuroradiol. 2021 Jun;31(2):383-390. doi: 10.1007/s00062-020-00909-y. Epub 2020 May 7.
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.
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.
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.
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.
与原发性脊髓肿块相比，磁共振成像（MRI）上的外周强化特征，即边缘征和火焰征，是脊髓髓内转移瘤（ISCM）的特异性表现。本研究比较了一种新发现——中心点征在ISCM与原发性髓内肿块中的出现频率。
本研究纳入了45例患有64个ISCM的患者以及64例患有64个原发性脊髓髓内肿块的对照患者，2名对病变类型不知情的放射科医生独立评估MR图像，以确定是否存在中心点征：即强化的髓内肿块中心或其附近的点状强化灶。比较了两组患者中该征象的出现频率。
共纳入了44例患者中的63个强化ISCM以及54例患者中的54个强化原发性脊髓肿块。在44例患者中，9%（4/44）的强化ISCM出现了中心点征，占强化ISCM的6%（4/63）；而在强化原发性脊髓肿块中未出现（0/54）（患者层面，p = 0.038）。在脊髓肿块中诊断ISCM的特异性为100%。中心点征仅在两个ISCM的轴位平面出现，在两个ISCM的轴位和矢状位平面出现。出现中心点征的两个ISCM同时也表现出了先前描述的边缘征和火焰征，另外两个仅表现出边缘征。
与原发性脊髓肿块相比，中心点征对ISCM不敏感，但具有高度特异性。ISCM中边缘征和/或火焰征可能同时出现，也可能不出现。
