Trident sign (neurosarcoidosis)
Updates to Article Attributes
The trident sign is a radiological (MRI) sign described in spinal cord neurosarcoidosis.
The sign is formed by the axial appearance of a longitudinally extensive transverse myelitis due to spinal cord neurosarcoidosis, whereby on a T1 post-contrast (gadolinium) MRI sequence, there is central canal enhancement accompanying crescent-shaped posterior subpial enhancement 1-3. This gives the appearance of a trident, a three-pronged spear 1-3.
It has been suggested that this is a useful sign in differentiating neurosarcoidosis from other causes of longitudinally extensive transverse myelitis, such as neuromyelitis optica spectrum disorder (NMOSD) 3. However, it should be noted that while it may be characteristic, the trident sign may not be commonly present in cases of spinal cord neurosarcoidosis; for example, it was not found in any cases in one large case series of patients with the condition 4. It is also not specific for neurosarcoidosis and can be seen in other pathologies (e.g. HTLV-1-associated myelopathy) 56.
History and etymology
The trident is a three-pronged lance used for spear fishing. In classical mythology, it was the weapon born by sea gods (Poseidon in Ancient Greece or Neptune in Roman mythology) 5. Although a similar weapon, the trishoola, with rounded tines, is also seen being carried in images of Hindu gods (Shiva and Durga) 5. The trident sign was first employed in the context of neurosarcoidosis in 2016 1.
-<p>The <strong>trident sign</strong> is a radiological (MRI) sign described in spinal cord <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a>.</p><p>The sign is formed by the axial appearance of a <a href="/articles/longitudinally-extensive-spinal-cord-lesion" title="Longitudinally extensive spinal cord lesion">longitudinally extensive transverse myelitis</a> due to spinal cord <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a>, whereby on a T1 post-contrast (gadolinium) MRI sequence, there is central canal enhancement accompanying crescent-shaped posterior subpial enhancement <sup>1-3</sup>. This gives the appearance of a trident, a three-pronged spear <sup>1-3</sup>.</p><p>It has been suggested that this is a useful sign in differentiating <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a> from other causes of <a href="/articles/longitudinally-extensive-spinal-cord-lesion" title="Longitudinally extensive spinal cord lesion">longitudinally extensive transverse myelitis</a>, such as <a href="/articles/neuromyelitis-optica-spectrum-disorder" title="Neuromyelitis optica spectrum disorder">neuromyelitis optica spectrum disorder (NMOSD)</a> <sup>3</sup>. However, it should be noted that while it may be characteristic, the trident sign may not be commonly present in cases of spinal cord neurosarcoidosis; for example, it was not found in any cases in one large case series of patients with the condition <sup>4</sup>. It is also not specific for neurosarcoidosis and can be seen in other pathologies (e.g. HTLV-associated myelopathy) <sup>5</sup>.</p><h4>History and etymology</h4><p>The trident is a three-pronged lance used for spear fishing. In classical mythology, it was the weapon born by sea gods (Poseidon in Ancient Greece or Neptune in Roman mythology) <sup>5</sup>. Although a similar weapon, the trishoola, with rounded tines, is also seen being carried in images of Hindu gods (Shiva and Durga) <sup>5</sup>. The trident sign was first employed in the context of <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a> in 2016 <sup>1</sup>.</p>- +<p>The <strong>trident sign</strong> is a radiological (MRI) sign described in spinal cord <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a>.</p><p>The sign is formed by the axial appearance of a <a href="/articles/longitudinally-extensive-spinal-cord-lesion" title="Longitudinally extensive spinal cord lesion">longitudinally extensive transverse myelitis</a> due to spinal cord <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a>, whereby on a T1 post-contrast (gadolinium) MRI sequence, there is central canal enhancement accompanying crescent-shaped posterior subpial enhancement <sup>1-3</sup>. This gives the appearance of a trident, a three-pronged spear <sup>1-3</sup>.</p><p>It has been suggested that this is a useful sign in differentiating <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a> from other causes of <a href="/articles/longitudinally-extensive-spinal-cord-lesion" title="Longitudinally extensive spinal cord lesion">longitudinally extensive transverse myelitis</a>, such as <a href="/articles/neuromyelitis-optica-spectrum-disorder" title="Neuromyelitis optica spectrum disorder">neuromyelitis optica spectrum disorder (NMOSD)</a> <sup>3</sup>. However, it should be noted that while it may be characteristic, the trident sign may not be commonly present in cases of spinal cord neurosarcoidosis; for example, it was not found in any cases in one large case series of patients with the condition <sup>4</sup>. It is also not specific for neurosarcoidosis and can be seen in other pathologies (e.g. <a href="/articles/htlv-1-associated-myelopathy" title="HTLV-1-associated myelopathy">HTLV-1-associated myelopathy</a>) <sup>6</sup>.</p><h4>History and etymology</h4><p>The trident is a three-pronged lance used for spear fishing. In classical mythology, it was the weapon born by sea gods (Poseidon in Ancient Greece or Neptune in Roman mythology) <sup>5</sup>. Although a similar weapon, the trishoola, with rounded tines, is also seen being carried in images of Hindu gods (Shiva and Durga) <sup>5</sup>. The trident sign was first employed in the context of <a href="/articles/neurosarcoidosis" title="Neurosarcoidosis">neurosarcoidosis</a> in 2016 <sup>1</sup>.</p>
References changed:
- 6. Dixon L, McNamara C, Dhasmana D, Taylor G, Davies N. Imaging Spectrum of HTLV-1-Related Neurologic Disease: A Pooled Series and Review. Neurol Clin Pract. 2023;13(3):e200147. <a href="https://doi.org/10.1212/CPJ.0000000000200147">doi:10.1212/CPJ.0000000000200147</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/37066106">Pubmed</a>
- Dixon L, McNamara C, Dhasmana D, Taylor GP, Davies N. Imaging Spectrum of HTLV-1-Related Neurologic Disease: A Pooled Series and Review. Neurol Clin Pract. 2023 Jun;13(3):e200147. doi: 10.1212/CPJ.0000000000200147. Epub 2023 Mar 27. PMID: 37066106; PMCID: PMC10092304.
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