PURPOSE: Information on abnormal diffusion-weighted imaging (DWI) patterns in bacterial meningitis (BM) is limited. This study aimed to investigate the frequency and patterns of DWI abnormalities in BM in patients with culture-positive BM. METHODS: The medical records of 14 consecutive patients with BM with magnetic resonance imaging evaluation, admitted to our hospital over the past 14 years, were reviewed. BM was defined by a cerebrospinal fluid (CSF) culture positive for bacteria, or the combination of CSF pleocytosis and a positive blood culture. RESULTS: Brain DWI abnormalities were identified in 13 (93 %) of the 14 patients and classified into six patterns: ischaemic stroke (n = 9), ventriculitis (n = 4), sulcal hyperintensity (n = 7), scattered hyperintensities surrounding the cerebral hemispheres (n = 6), middle meningeal arterial sign (n = 5), or abscess (n = 1). The causes of ischaemic stroke included infective endocarditis (n = 4), vasculitis (vasculopathy
n = 2), and unclassified (n = 3). CONCLUSION: DWI abnormalities in BM were very frequent. Based on the high frequency and wide spectrum of DWI abnormalities in BM, we suggest performing DWI for all patients with BM.