Spinal cord MRI
Typical spinal cord MRI changes in both children and adult MOGAD
patients are TM, often in the form of LETM, but also as short myelitis
(46). MOGAD patients commonly present with LETM affecting the cervical
and/or thoracic cord (41,47,51,73). LETM is also a main radiological
feature in AQP4-NMOSD (46). Compared to AQP4-TM, conus involvement and
multiple spinal cord lesions have been more frequently observed in
MOG-TM (41,93,94). Short myelitis, which is typical of MS, can similarly
be found in MOG-TM, however it is not found often in AQP4-TM
(27,41,47,95,96). MOG-TM may present in spinal cord MRI as a
hyperintense “H-sign” observed in the axial orientation, while imaged
as a longitudinal thin vertical line in the T2-weighted sagittal plane
image. This suggests a predominant affection of the spinal cord grey
matter, as opposed to AQP4-TM, which may not be as centrally located in
the cord (41,97,98). Gadolinium contrast-enhancement of spinal cord
lesions is less common in MOG-TM compared to lesions in MS or AQP4-TM
(41). Importantly, spinal cord MRI can initially be normal in MOGAD,
although rare (99).