title: The prognostic role of magnetic resonance imaging and single-photon emission computed tomography in viral encephalitis.
abstract: BACKGROUND
  There is a paucity of studies evaluating the prognostic role of magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) changes in viral encephalitis.
  
  
  OBJECTIVE
  To study MRI and SPECT changes in patients with viral encephalitis, and to correlate these changes with clinical findings and outcome.
  
  
  METHODS
  During 1997-2006, 31 encephalitis patients (aged 2-60 years; nine females, 22 males) underwent both MRI and SPECT studies. Their demographic and clinical data and 6-month outcome were recorded. For the diagnosis of encephalitis, polymerase chain reaction (PCR) and IgM enzyme-linked immunosorbent assay (ELISA) were carried out. Cranial MRI was done on a 1.5T scanner, and 99mTc ethylene cysteine dimer (ECD) SPECT using a gamma camera. Outcome was defined at 6 months as complete, partial, or poor recovery.
  
  
  RESULTS
  19 patients had Japanese encephalitis (JE), one had herpes simplex encephalitis (HSE), and 11 had nonspecific encephalitis. Movement disorders were present in 21, parkinsonian features in 19, and dystonia in 16 patients. MRI was abnormal in 20 patients, and revealed thalamic involvement in 17, basal ganglia in eight, brainstem in 11, and cortical in two. SPECT revealed hypoperfusion in 22 patients, which was cortical in 11, thalamic in 10, basal ganglia in six, and midbrain in one. Cortical involvement was more frequently found by SPECT and brainstem involvement by MRI. Outcome of encephalitis did not differ in the different groups of encephalitis and MRI changes.
  
  
  CONCLUSIONS
  MRI and SPECT show a spectrum of findings in encephalitis, but these do not correlate with 6-month outcome.
authors.affiliation: Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India. drukmisra@rediffmail.com
authors.forename: U K
authors.initials: UK
authors.lastname: Misra
authors.forename: J
authors.initials: J
authors.lastname: Kalita
authors.forename: A
authors.initials: A
authors.lastname: Srivastav
authors.forename: P K
authors.initials: PK
authors.lastname: Pradhan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D018792:Encephalitis, Viral / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011379:Prognosis; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*