Abstract
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.
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Authors and Affiliations
Contributions
Ajay A. Madhavan, MD: Manuscript writing, manuscript revision, Image review, Study conception. Felix E. Diehn, MD: Study conception, Manuscript writing, Image review. Jeffrey B. Rykken, MD: Manuscript revision, Study conception. John T. Wald, MD: Manuscript revision, Study conception. Chris P. Wood, MD: manuscript revision, study conception. Kara M. Schwartz, MD: manuscript revision, study conception. Timothy J. Kaufmann, MD: manuscript revision, study conception. Christopher H. Hunt, MD: manuscript revision, image review; study conception. Dong Kun Kim: manuscript revision, study conception. Laurence J. Eckel, MD: manuscript revision, study conception.
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Conflict of interest
A.A. Madhavan, F.E. Diehn, J.B. Rykken, J.T. Wald, C.P. Wood, K.M. Schwartz, T.J. Kaufmann, C.H. Hunt, D.K. Kim and L.J. Eckel declare that they have no competing interests.
Ethical standards
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required. No funding was received for this study.
Additional information
Paper previously presented at: Annual Meeting of the American Society of Spine Radiology, 14–18 February 2018, Scottsdale AZ
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Madhavan, A.A., Diehn, F.E., Rykken, J.B. et al. The Central Dot Sign. Clin Neuroradiol 31, 383–390 (2021). https://doi.org/10.1007/s00062-020-00909-y
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DOI: https://doi.org/10.1007/s00062-020-00909-y