Callosal lesions on magnetic resonance imaging with multiple sclerosis, neuromyelitis optica spectrum disorder and acute disseminated encephalomyelitis

Objective: To clarify the features of callosal lesions on magnetic resonance imaging (MRI) in Multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and acute disseminated encephalomyelitis (ADEM). Methods: Chinese patients diagnosed with MS (n = 33), NMOSD (n = 31), and ADEM (n = 18) were enrolled. Characteristics of lesions in corpus callosum were evaluated with 1.5 Tesla MRI scanners. Chi-squared test (Fisher's exact test) was used to analyze the data. Results: In corpus callosum, NMOSD and ADEM lesions tend to have a diffuse distribution (p = 0.006, p = 0.033) and blurred margins (p < 0.001, p = 0.017), when compared with MS; lesions in NMOSD were less ovoid (p = 0.006), while fewer lesions in ADEM existed in the rostrum and genu (p = 0.002). NMOSD has the most heterogeneous intensity on post-enhancement sequences (p = 0.016, p = 0.001). Radial-like lesions were more common in MS and NMOSD (p = 0.019, p < 0.001). Conclusion: MS lesions were most likely focally-localized with clear margins. Radial callosal lesions are characteristic of MS and NMOSD but rarely seen in ADEM. The signal intensities of the lesion were the most heterogeneous in NMOSD. Therefore, the lesion patterns in corpus callosum may serve as a useful clue for correct diagnosis, facilitating early treatment.