title: New Findings, Classification and Long-Term Follow-Up Study Based on MRI Characterization of Brainstem Encephalitis Induced by Enterovirus 71.
abstract: BACKGROUND
  To report the diversity of MRI features of brainstem encephalitis (BE) induced by Enterovirus 71. This is supported by implementation and testing of our new classification scheme in order to improve the diagnostic level on this specific disease.
  
  
  METHODS
  Neuroimaging of 91 pediatric patients who got EV71 related BE were hospitalized between March, 2010 to October, 2012, were analyzed retrospectively. All patients underwent pre- and post-contrast MRI scan. Thereafter, 31 patients were randomly called back for follow-up MRI study during December 2013 to August 2014. The MRI signal patterns of BE primary lesion were analyzed and classified according to MR signal alteration at various disease stages. Findings in fatal and non-fatal cases were compared, and according to the MRI scan time point during the course of this disease, the patients' conditions were classified as 1) acute stage, 2) convalescence stage, 3) post mortem stage, and 4) long term follow-up study.
  
  
  RESULTS
  103 patients were identified. 11 patients did not undergo MRI, as they died within 48 hours. One patient died on 14th day without MR imaging. 2 patients had postmortem MRI. Medical records and imaging were reviewed in the 91 patients, aged 4 months to 12 years, and two cadavers who have had MRI scan. At acute stage: the most frequent pattern (40 patients) was foci of prolonged T1 and T2 signal, with (15) or without (25) contrast enhancement. We observed a novel pattern in 4 patients having foci of low signal intensity on T2WI, with contrast enhancement. Another pattern in 10 patients having foci of contrast enhancement without abnormalities in T1WI or T2WI weighted images. Based on 2 cases, the entire medulla and pons had prolonged T1 and T2 signal, and 2 of our postmortem cases demonstrated the same pattern. At convalescence stage, the pattern observed in 4 patients was foci of prolonged T1 and T2 signal without contrast enhancement. Follow-up MR study of 31 cases showed normal in 26 cases, and demonstrated foci of prolonged T1 and T2 signal with hyper-intensity on FLAIR in 3 cases, or of prolonged T1 and T2 signal with hypo-intensity on FLAIR in 2 cases. Most importantly, MR findings of each case were thoroughly investigated and classified according to phases and MRI signal alteration.
  
  
  CONCLUSIONS
  This study has provided enhanced and useful information for the MRI features of BE induced by EV71, apart from common practice established by previous reports. In addition, a classification scheme that summarizes all types of features based on the MRI signal at the four different stages of the disease would be helpful to improve the diagnostic level.
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.|Department of Radiology, Guangdong General Hospital, Guangdong, China.|School of Medicine, Southern Medical University, Guangdong, China.
authors: Hongwu
authors: http://orcid.org/0000-0002-7832-3702
authors: H
authors: Zeng
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.
authors: Feiqiu
authors: F
authors: Wen
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.
authors: Wenxian
authors: W
authors: Huang
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.
authors: Yungen
authors: Y
authors: Gan
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.
authors: Weibin
authors: W
authors: Zeng
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.
authors: Ranran
authors: R
authors: Chen
authors: Radiology, Neurology and Pediatric Intensive Care Unit Department, Shenzhen Children's Hospital, Guangdong, China.
authors: Yanxia
authors: Y
authors: He
authors: Department of Radiology, College of Medicine, University of Kentucky, Lexington, KY, United States of America.
authors: Yonker
authors: Y
authors: Wang
authors: Department of Radiology, Guangdong General Hospital, Guangdong, China.
authors: Zaiyi
authors: Z
authors: Liu
authors: Department of Radiology, Guangdong General Hospital, Guangdong, China.|School of Medicine, Southern Medical University, Guangdong, China.
authors: Changhong
authors: C
authors: Liang
authors: School of Medicine, Western Sydney University, New South Wales, Australia.
authors: Kelvin K L
authors: KK
authors: Wong
mesh_terms: D001933:Brain Stem / Q000000981:diagnostic imaging* / Q000821:virology*; D002648:Child; D002675:Child, Preschool; D004660:Encephalitis / Q000150:complications / Q000175:diagnosis* / Q000821:virology*; D029821:Enterovirus A, Human; D004769:Enterovirus Infections / Q000175:diagnosis* / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010641:Phenotype