Laboratory investigations, imaging, and cerebrospinal fluid analysis are crucial in the diagnosis of encephalitis. Magnetic resonance imaging (MRI) findings may be nonspecific or specific and plays a major role in the diagnosis of encephalitis and predicting the possible cause.

Can encephalitis be missed on MRI?

To distinguish encephalitis from other causes of encephalopathy, key features include presence of fever, CSF pleocytosis, or MRI or EEG changes compatible with encephalitis (table 1). Although such definitions likely capture most patients with clinically significant encephalitis, some will be missed.

Can you have encephalitis with a normal MRI?

The brain MRI is normal in approximately 60% of patients with anti-NMDAR encephalitis. Very few studies have systematically investigated neuroimaging in all-cause encephalitis. Research is needed to better define associations between neuroimaging results and specific encephalitis aetiologies.