Brain MRI Findings in Pediatric-Onset Neuromyelitis Optica Spectrum Disorder: Challenges in Differentiation from Acute Disseminated Encephalomyelitis

Abstract

BACKGROUND AND PURPOSE:Differentiating pediatric-onset neuromyelitis optica spectrum disorder from acute disseminated encephalomyelitis could be challenging, especially in cases presenting with only brain manifestations. Our purpose was to investigate brain MR imaging features that may help distinguish these 2 entities. MATERIALS AND METHODS:We retrospectively examined initial brain MR imaging studies of 10 patients with pediatric-onset neuromyelitis optica spectrum disorder (female/male ratio, 7:3) and 10 patients with acute disseminated encephalomyelitis (female/male ratio, 2:8). The mean age of the patients was 10.3 Ϯ 5.6 and 8.7 Ϯ 5.3 years, respectively. Brain lesions were evaluated with respect to location, extent, expansion, T1 hypointensity, contrast enhancement/pattern, and diffusion characteristics. The 2 test (Yates or Fisher exact 2 tests) was used to compare differences between groups. RESULTS:Cerebral subcortical Ϯ juxtacortical and pons Ϯ middle cerebellar peduncle were the most frequent locations involved in both neuromyelitis optica spectrum disorder (n ϭ 5 and 4, respectively) and acute disseminated encephalomyelitis (n ϭ 9 and 7, respectively). Thalamic lesions were more frequent in acute disseminated encephalomyelitis (P ϭ .020) and were detected only in 1 patient with neuromyelitis optica spectrum disorder. None of the patients with neuromyelitis optica spectrum disorder had hypothalamic, internal capsule, or cortical lesions. The internal capsule involvement was found to be significantly different between groups (P ϭ .033). There was no significant difference in terms of extent, expansion, T1 hypointensity, contrast enhancement/pattern, and diffusion characteristics. CONCLUSIONS:Although there is a considerable overlap in brain MR imaging findings, thalamic and internal capsule involvement could be used to differentiate pediatric-onset neuromyelitis optica spectrum disorder from acute disseminated encephalomyelitis. ABBREVIATIONS: ADEM ϭ acute disseminated encephalomyelitis; anti-AQP4 ϭ anti-aquaporin-4; AQP4 ϭ aquaporin-4; NMOSD ϭ neuromyelitis optica spectrum disorder

A Comparison of Pediatric- and Adult-Onset Aquaporin-4 Immunoglobulin G–Positive Neuromyelitis Optica Spectrum Disorder: A Review of Clinical and Radiographic Characteristics

“…9 The presence of brain lesions has been proposed to be more frequent in children with neuromyelitis optica spectrum disorder previously. 10 This is supported by our findings, as we observed acute brainstem, diencephalic, and cerebral syndromes more frequently in cases with pediatric-onset neuromyelitis optica spectrum disorder compared to adult-onset.…”

“…Therefore, it should be considered as a possible differential diagnosis in pediatric patients with acute disseminated encephalomyelitis presentations. Thalamic involvement has been proposed as a potential differentiating factor previously 10 and we also observed such diencephalic involvement.…”

“…Such radiographic similarities to acute disseminated encephalomyelitis have been described previously. 10 However, although there may be overlapping MRI features with acute disseminated encephalomyelitis, symptomatic cerebral syndrome in neuromyelitis optica spectrum disorder is a separate entity including its different clinical course with a high risk of potentially devastating relapses in contrast to the usually monophasic course of acute disseminated encephalomyelitis. Therefore, it should be considered as a possible differential diagnosis in pediatric patients with acute disseminated encephalomyelitis presentations.…”

Mirror-Image Lesions in Sequential Relapses of AQP4-Positive Neuromyelitis Optica Spectrum Disorder

“…Particularly in the past when AQP4 and MOG serologic testing was less reliable, it could be difficult at times to distinguish the first episode of NMOSD from ADEM, as ADEM can also present with LETM, large hemispheric lesions, as well as diencephalic and brainstem lesions. In one study, thalamic and internal capsule involvement were found to occur more frequently in ADEM than in NMOSD (12). Our patient's initial presentation with thalamic lesions, meningismus, fevers, and a seizure led the treating neurologist to favor a diagnosis of ADEM after the first attack.…”

A window into the future? MRI for evaluation of neuromyelitis optica spectrum disorder throughout the disease course

“… 32 The presence of thalamic and internal capsule lesions, which are seen in ADEM but are infrequent in NMOSD, may help to distinguish NMOSD from this important differential diagnosis in childhood. 93 LETM is a common feature on spinal cord MRI, but may more often be caused by other neuroinflammatory conditions including MOGAD and monophasic transverse myelitis. 92 …”