Reversible inferior colliculus lesion in metronidazole-induced encephalopathy: magnetic resonance findings on diffusion-weighted and fluid attenuated inversion recovery imaging.
OBJECTIVE
This is to present reversible inferior colliculus lesions in metronidazole-induced encephalopathy, to focus on the diffusion-weighted imaging (DWI) and fluid attenuated inversion recovery (FLAIR) imaging.


METHODS
From November 2005 to September 2007, 8 patients (5 men and 3 women) were diagnosed as having metronidazole-induced encephalopathy (age range; 43-78 years). They had been taking metronidazole (total dosage, 45-120 g; duration, 30 days to 2 months) to treat the infection in various organs. Initial brain magnetic resonance imaging (MRI) were obtained after the hospitalization, including DWI (8/8), apparent diffusion coefficient (ADC) map (4/8), FLAIR (7/8), and T2-weighted image (8/8). Follow-up MRIs were performed on 5 patients from third to 14th days after discontinuation of metronidazole administration. Findings of initial and follow-up MRIs were retrospectively evaluated by 2 neuroradiologists by consensus, to analyze the presence of abnormal signal intensities, their locations, and signal changes on follow-up images.


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). High-signal intensity lesions on DWI tended to show low signal intensity on ADC map (3/4), but in one patient, high signal intensity was shown at bilateral dentate nuclei on not only DWI but also ADC map. All the lesions in dentate, inferior colliculus, pons, and medullas had been resolved completely on follow-up MRIs in 5 patients, but in 1 patient of them, corpus callosal lesion persisted.


CONCLUSIONS
Reversible inferior colliculus lesions could be considered as the characteristic for metronidazole-induced encephalopathy, next to the dentate nucleus involvement.
Department of Radiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea.
Seong Soo
SS
Lee
Sang-Hoon
SH
Cha
Seung Young
SY
Lee
Chang June
CJ
Song
D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000009:adverse effects*; D001929:Brain Edema / Q000139:chemically induced* / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D004401:Dysarthria / Q000139:chemically induced; D005260:Female; D020234:Gait Ataxia / Q000139:chemically induced; D006801:Humans; D007245:Inferior Colliculi / Q000473:pathology*; D008297:Male; D008795:Metronidazole / Q000009:adverse effects*; D008875:Middle Aged; D012075:Remission, Spontaneous; D012189:Retrospective Studies; D014717:Vertigo / Q000139:chemically induced
D000890:Anti-Infective Agents; D008795:Metronidazole