Idiopathic acute transverse myelitis in children: an analysis and discussion of MRI findings.

Background: There is lack of reported magnetic resonance imaging (MRI) studies of idiopathic acute transverse myelitis (ATM) in children.

Objective: To describe the imaging features of idiopathic ATM in children.

Methods: We retrospectively analyzed the spinal MRI findings of children diagnosed with ATM. The anatomic regions, vertebral segmental length, gray or white matter involvement, cord expansion and gadolinium enhancement were examined.

Results: A total of 27 children were diagnosed with isolated monophasic ATM with a mean follow-up of 5.2 years. Two children later diagnosed with neuromyelitis optica were excluded from the pediatric ATM cohort. None of the patients had a subsequent diagnosis of multiple sclerosis. The mean age of onset was 9.5 years (0.5-16.9 years). Spinal MRIs were abnormal in 21 (78%). The mean interval between symptom onset and the MRI was 1.7 days (0-19 days). Central cord hyperintensity involving gray matter was seen in all patients. A majority (67%) of the patients demonstrated long segment lesions with a mean segment length of 6.4.

Conclusions: We conclude that central cord inflammation extending over three or more segments is the most common finding of idiopathic monophasic transverse myelitis in children. The risk of multiple sclerosis in children who experience isolated transverse myelitis as a first demyelinating event is low.