TRIDENT |
LOCATION
|
SAGITTAL T2 |
POST CONTRAST SAGGITAL |
Other features |
|
Cervical/Thoracic
Single
Less often: multifocal1
Distribution similar to NMOSD6
|
Longitudinally extensive T2-hyperintense lesion (in 80%
of patients2) involving the central cord (that would be
indistinguishable from an NMOSD lesion based on
T2-weighted images alone).
These lesions tend to be relatively long: mean of 6
vertebral segments3.
Short, bulky tumour-like lesions are also described3.
|
Almost universal: intense, homogenous4, dorsal subpial5, that must
extend 2 or more vertebral segments. This finding is significantly
more common in sarcoid myelopathy than in AQP4-IgG–positive
NMOSD myelitis6. Ring enhancement is commoner in NMOSD.
Enhancement may persist for over 6 months, and take years to resolve4.
Leptomeningeal enhancement may co-exist with dorsal subpial enhancement1.
Ventral subpial enhancement is also described3, frequently associated
with disc degeneration. 6
|
Swelling
(non specific)
|
|
|
|
|
|

|

|

|

From: Ref 1
|

|
|
AXIAL T2
|
POST CONTRAST |
|
Axial trident5. |


From: Ref 4
|


From: Ref 1
|
References
1 Lopez Chiriboga S, Flanagan EP. Myelitis and Other Autoimmune Myelopathies. Contin Lifelong Learn Neurol 2021; 27: 62–92.
2 Sohn M, Culver DA, Judson MA, Scott TF, Tavee J, Nozaki K. Spinal cord neurosarcoidosis. Am J Med Sci 2014; 347: 195–8.
3 Murphy OC, Salazar-Camelo A, Jimenez JA, et al. Clinical and MRI phenotypes of sarcoidosis-associated myelopathy. Neurol Neuroimmunol neuroinflammation 2020; 7.
4 Flanagan EP. Autoimmune myelopathies, 1st edn. Elsevier B.V., 2016 DOI:10.1016/B978-0-444-63432-0.00019-0.
5 Mustafa R, Passe TJ, Lopez-Chiriboga AS, et al. Utility of MRI Enhancement Pattern in Myelopathies With Longitudinally Extensive T2 Lesions. Neurol Clin Pract 2021; 11: E601–11.
6 Flanagan EP, Kaufmann TJ, Krecke KN, et al. Discriminating long myelitis of neuromyelitis optica from sarcoidosis. Ann Neurol 2016; 79: 437–47.