Diffuse and heterogeneous T2-hyperintense lesions in the splenium are characteristic of neuromyelitis optica.
BACKGROUND
Callosal lesions in multiple sclerosis (MS) are usually focal, involving the inferior aspect of the corpus callosum on brain magnetic resonance imaging (MRI), but little is known about callosal lesions in neuromyelitis optica (NMO).


OBJECTIVE
To clarify MRI abnormalities in callosal lesions of NMO.


METHODS
Japanese patients with NMO (n=28) or MS (n=22) were assessed. The distributions and appearances of callosal lesions were evaluated on a brain mid-sagittal T2-weighted image (T2WI) or a fluid-attenuated inversion recovery image with a 1.5T MRI scanner. Logistic regression analysis identified which characteristics of the callosal lesions were useful for discriminating NMO from MS.


RESULTS
Callosal lesions were present in 79% of NMO and 82% of MS patients. Callosal abnormalities of NMO, including splenial lesions (57% in NMO versus 27% in MS, odds ratio (OR)=4.23, p=0.04), diffusely spreading lesions from the lower to upper edges of the corpus callosum (71% versus 23%, OR=7.18, p=0.0024), and heterogeneous T2 hyperintense lesions (71% versus 9%, OR=44.3, p=0.0006), were feasible for discriminating NMO from MS.


CONCLUSIONS
Diffuse and heterogeneous T2 hyperintense splenial lesions were characteristic of NMO. These findings could help distinguish NMO from MS on MRI.
Department of Neurology, Chiba University, Japan. takamkt2@gmail.com
Takahiro
T
Makino
Shoichi
S
Ito
Masahiro
M
Mori
Tadahiro
T
Yonezu
Yoshitsugu
Y
Ogawa
Satoshi
S
Kuwabara
D000328:Adult; D003337:Corpus Callosum / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*; D009471:Neuromyelitis Optica / Q000473:pathology*; D012189:Retrospective Studies; D013116:Spinal Cord / Q000473:pathology