The neuroimaging spectrum of subacute sclerosing panencephalitis: a systematic review

We conducted a comprehensive analysis of spectrum of neuroimaging findings in Subacute Sclerosing Panencephalitis (SSPE) across case reports and cohort studies.

A systematic review was conducted as per PRISMA guidelines. Electronic databases were searched from inception using predefined terms related to SSPE and neuroimaging. Eligible studies included confirmed cases with reported imaging findings from case reports, case series, and cohort studies.

Among 461 reported cases, neuroimaging was performed in 456 (98.9%), with MRI in 394 (85.5%) and CT in 58 (12.6%). White-matter abnormalities were identified in 431 (93.5%), most commonly diffuse bilateral (132, 28.6%), periventricular (104, 22.6%), subcortical (71, 15.4%), and posterior parieto-occipital-predominant patterns (63, 13.7%). Cortical involvement was present in 247 (53.6%), including diffuse hemispheric changes (74, 16.1%) and posterior predominance (68, 14.8%). Deep gray matter lesions occurred in 79 (17.2%), involving basal ganglia (47, 10.2%) and thalamus (23, 5.0%), while brainstem abnormalities were observed in 34 (7.4%). Diffusion restriction was reported in 52 (11.3%), contrast enhancement in 38 (8.2%), and cerebral atrophy in 162 (35.1%), including progressive atrophy in 63 (13.7%). Imaging mimics included ocular-first/visual pathway-predominant patterns (46, 10.0%), autoimmune encephalitis/ADEM-like patterns (37, 8.0%), leukodystrophy-like changes (31, 6.7%), stroke-like presentations (29, 6.3%), and basal ganglia-predominant forms (26, 5.6%).

Neuroimaging in SSPE shows predominant bilateral white matter involvement with posterior distribution, variable cortical and deep gray extension, progressive atrophy, limited enhancement, and frequent radiological mimics, reflecting a stage-evolving heterogeneous process.