MRI Clues Help Distinguish Neuromyelitis Optica From MS
Bright spotty lesions on MRI help distinguish neuromyelitis optica from MS, according to this study
The appearance of bright spotty lesions (BSLs) on spinal MRIs may be a valuable new tool in helping clinicians distinguish between neuromyelitis optica (NMO) and multiple sclerosis (MS), according to findings from a new study.
The study was published online July 4 in the Multiple Sclerosis Journal (Yonezu et al., 2013).
While it can be difficult to differentiate NMO from MS clinically, the researchers stressed that it is crucial to do so since management of the two conditions varies considerably.
In patients with NMO, intensive treatments such as plasmapheresis may be used as well as oral corticosteroids and immunosuppressive therapy. However, interferon beta therapy, shown to be of benefit in patients with MS, can increase relapses of NMO.
Explaining their rationale for undertaking the present study, lead author Tadahiro Yonezu, M.D., of Chiba University in Japan, along with colleagues, wrote, "Spinal magnetic resonance imaging (MRI) finding of longitudinally extensive spinal cord lesions (LESCL) extending over three vertebral segments and involvements of spinal central gray matter have been reported in patients with neuromyelitis optica (NMO)."
Aiming to find out whether such lesions, which are bright and spotty in appearance, might be used to help distinguish between patients with NMO and MS, these researchers assessed spinal MRIs of 24 consecutive patients with NMO and 34 patients with MS. For study purposes the investigators defined BSLs as very hyperintense spotty lesions on axial T2WI.
The researchers also gauged the length, distribution, signal homogeneity, size, and presence of contrast-enhanced lesions.
"The striking finding was that BSLs were seen in more than half of the patients with NMO (sensitivity = 54%) and in only one patient with MS (specificity = 97%)," the researchers wrote.
More specifically, they observed LESCLs in 67% of patients with NMO. They saw BSLs in 63% of patients who showed no evidence of LESCLs. However, they found BSLs or LESCLs in 88% of patients with NMO.
Further, the researchers saw three additional features more frequently in NMO patients than in patients with MS: inhomogeneous lesions, transversally extensive lesions, and central lesions.
In conclusion, they wrote, "BSLs are a newly defined spinal MRI finding specifically seen in NMO. In combination with LESCL, BSLs can help differentiate patients with NMO from those with MS with higher sensitivity than LESCL alone."
Key open questions
- Will the reliability of “bright spotty lesions” on spinal MRI be confirmed, in widespread clinical use, to be a useful diagnostic tool?
- What pathophysiologic differences account for the disparity in frequency of BSLs in patients with NMO compared with MS?
The authors have disclosed no relevant financial interests.