I tvivlstilfælde bør yderligere undersøgelser overvejes så som magnetisk resonans- skanning (MRI) helst med kontraststof, cerebrospinalvæske (CSF) test for JC viral DNA og gentagen neurologisk vurdering.
If any doubt exists, further evaluation, including Magnetic Resonance Imaging (MRI) scan preferably with contrast, cerebrospinal fluid (CSF) testing for JC viral DNA and repeat neurological assessment, should be considered.