Table 3:

Selected entities often mistaken for RIS

EntityDistinguishing Clinical FeaturesDistinguishing Imaging FeaturesImportant Keys to Diagnosis
Toxins/drug-relatedAltered mental status changes during intoxication, history of substance abuseDeep gray matter frequently involved, symmetric lesionsUrine and serum toxicology tests
Age-related leukoaraiosisOlder individual, cardiovascular risk factorsSmall (<3 mm), nonenhancing lesions in periventricular and deep white matter, coexistent striatocapsular lacunar disease, absence of callososeptal lesions/Dawson fingers–type lesionsLacunar disease and atypical white matter lesions for RIS in an older individual
MigrainesHeadache or aura predominatesPredominantly subcortical white matter lesions that are small (<3 mm) and do not enhance, few periventricular lesionsHeadache history and lack of typical imaging features consistent with RIS
VasculitisEpisodic neurologic symptoms with superimposed strokesGray and white matter lesions coexist, may have enhancing vessel wall and/or leptomeningeal enhancement, MRA with stenosesSystemic symptoms present, elevated erythrocyte sedimentation rate and/or C-reactive protein level, extra-/intracranial vessels abnormal, brain biopsy
CADASILStrokelike episodes, family history of similar clinical syndromeWhite matter disease favoring anterior temporal tip subcortical regions, external capsule, presence of lacunar infarctsGenetic testing diagnostic
Collagen vascular diseasesClinical history of arthritis, long-standing chronic disease, episodicGray and white matter lesions ± vasculitis, occasional encephalitisClinical symptoms of a systemic disorder and presence of serologic autoantibodies/inflammatory markers
ADEMEncephalitis, seizures, children > adults, history of viral/vaccine prodromeGray matter disease predominates, more diffuse enhancement, may have positive findings on DWIHistory of prodromal virus infection or vaccination, encephalopathic
PosttraumaticHistory of ≥1 traumatic, sports-related eventFavors gray-white matter junction, hemorrhagic products present, classic tears in splenium-brain stem deep gray matterHemorrhage and stereotypical locations of disease at shearing sites
  • Note:—ADEM indicates acute disseminated encephalomyelitis.