In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: RESULTS : Initial MRIs showed abnormal high signal intensities on DWI and FLAIR ( or T2 - weighted image ) at the dentate nucleus ( 8 / 8 ) , inferior colliculus ( 6 / 8 ) , corpus callosum ( 2 / 8 ) , pons ( 2 / 8 ) , medulla ( 1 / 8 ) , and bilateral cerebral white matter ( 1 / 8 ) .
### Output Text:
RESULTS : Initial MRIs showed abnormal high signal intensities on DWI and FLAIR ( or T2 - weighted image ) at the dentate nucleus ( 8 / 8 ) , inferior colliculus ( 6 / 8 ) , corpus callosum ( 2 / 8 ) , pons ( 2 / 8 ) , medulla ( 1 / 8 ) , and bilateral cerebral white matter ( 1 / 8 ) . 