Table 1:

Proposed diagnostic criteria for RIS by Okuda et al⁹

Inclusion Criteria	Exclusion Criteria
CNS white matter lesions on MR imaging that are ovoid, well-circumscribed, >3 mm, and homogeneously hyperintense on T2-weighted images with or without involvement of the corpus callosum	CNS lesions in a vascular pattern Historical accounts of remitting clinical symptoms consistent with neurologic dysfunction
CNS lesions fulfill 3 of 4 Barkof criteria 1) One gadolinium-enhancing lesion or 9 T2-hyperintense lesions if no gadolinium-enhancing lesions 2) At least 1 infratentorial lesion 3) At least 1 juxtacortical lesion, and 4) At least 3 periventricular lesions	MR imaging anomalies can be explained by the direct physiologic effects of substances (recreational drug abuse, toxic exposure) or a medical condition MR imaging phenotypes suggestive of leukoaraiosis (small-vessel ischemic disease) or extensive white matter pathology lacking involvement of the corpus callosum
MR imaging anomalies do not account for clinically apparent impairment in social, occupational, or generalized areas of functioning	White matter lesions are better accounted for by another medical condition