Brighter spotty lesions (BSLs) on spinal magnetic resonance imaging (MRI) scans may be useful to distinguish aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) from myelin oligodendrocyte glycoprotein antibody disease (MOGAD), as published in the Multiple Sclerosis Journal.

These results were found to be dependent on a precise definition of a BSL. Studies show that BSLs are more hyperintense on axial T2-weighted MRI scans than the usual T2-hyperintense lesion. However, not all studies use an explicit definition of BSLs.

“We used the term ‘brighter’ spotty lesion—in contrast to ‘bright’ spotty lesion—to clearly reflect updates to our research lexicon,” Hyun et al explained.

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They found BSLs in 30% (18/61) of participants with AQP4-NMOSD, but not in patients with MOGAD (n=49, P <.0001). In addition, they observed longitudinally extensive transverse myelitis (LETM) in 89% (54/61) of patients with AQP4-NMOSD and 63% (31/49) of patients with MOGAD (P =.0026).

BSLs were observed in 2 patients with AQP4-NMOSD but without evidence of LETM (n=7). Hyun et al did not identify any difference between groups in other axial findings as T1 hypointense lesions and gadolinium enhancements.

The percentage of patients with AQP4-NMOSD and MOGAD presenting with BSLs was consistent with previous reports that applied the same BSL definition. In contrast, 2 studies, which defined BSL as “T2 hyperintense spotty lesion” or “bright spots,” reported BSLs in 50% of patients with MOGAD.

“These findings highlight the importance of proper application of BSLs in practice,” Hyun et al highlighted. However, they also acknowledge that their study had some limitations, such as the lack of consistency in the MRI protocols and the scarce variability in the study cohort.

Therefore, additional studies are needed to clarify the potential role of BSLs as characteristic features for revising the diagnostic criteria of AQP4-NMOSD.

Reference

Hyun J-W, Lee HL, Park J, et al. Brighter spotty lesions on spinal MRI help differentiate AQP4 antibody-positive NMOSD from MOGAD. Mult Scler J. Published online December 6, 2021. doi:10.1177/13524585211060326

AQP4-NMOSD MOGAD Neurologists Ophthalmologists Physiatrist