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Imaging in viral infections of the central nervous system: can images speak for an acutely ill brain?


Viral infections involving the central nervous system (CNS) may result from a wide variety of agents and have clinically overlapping manifestations. The diagnosis is often made based on a combination of the clinical exam, local epidemiology, imaging, and biochemical findings. Despite the advances in medicine and imaging, the diagnosis often remains elusive. Imaging, however, still plays a vital role in suggesting the diagnosis in typical cases, excluding potential mimics, and in evaluating changes with therapy. Herein, the authors present a review of various common and rare viral encephalitides with emphasis on the imaging literature.

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  1. 1.

    Solbrig MV, Hasso AN, Jay CA (2008) CNS viruses—diagnostic approach. Neuroimaging Clin N Am 18(1):1–18 vii

    Article  PubMed  Google Scholar 

  2. 2.

    Gupta RK et al (2012) Imaging of central nervous system viral diseases. J Magn Reson Imaging 35(3):477–491

    Article  PubMed  Google Scholar 

  3. 3.

    Moritani T et al (2014) Viral infections and white matter lesions. Radiol Clin North Am 52(2):355–382

    Article  PubMed  Google Scholar 

  4. 4.

    Bulakbasi N, Kocaoglu M (2008) Central nervous system infections of herpesvirus family. Neuroimaging Clin N Am 18(1):53–84 viii

    Article  PubMed  Google Scholar 

  5. 5.

    Bonnici-Mallia M et al (2016) Herpes simplex encephalitis: unusual imaging appearances. BMJ Case Rep 2016. doi:10.1136/bcr-2016-214993

  6. 6.

    Leonard JR et al (2000) MR imaging of herpes simplex type 1 encephalitis in infants and young children: a separate pattern of findings. AJR Am J Roentgenol 174(6):1651–1655

    CAS  Article  PubMed  Google Scholar 

  7. 7.

    Vossough A et al (2008) Imaging findings of neonatal herpes simplex virus type 2 encephalitis. Neuroradiology 50(4):355–366

    Article  PubMed  Google Scholar 

  8. 8.

    Tang JW et al (2003) Brain stem encephalitis caused by primary herpes simplex 2 infection in a young woman. J Neurol Neurosurg Psychiatry 74(9):1323–1325

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  9. 9.

    Weaver S, Rosenblum MK, DeAngelis LM (1999) Herpes varicella zoster encephalitis in immunocompromised patients. Neurology 52(1):193–195

    CAS  Article  PubMed  Google Scholar 

  10. 10.

    Chretien F et al (1993) Acute varicella-zoster virus ventriculitis and meningo-myelo-radiculitis in acquired immunodeficiency syndrome. Acta Neuropathol 86(6):659–665

    CAS  Article  PubMed  Google Scholar 

  11. 11.

    Aygun N et al (1998) Multifocal varicella-zoster virus leukoencephalitis in a patient with AIDS: MR findings. AJNR Am J Neuroradiol 19(10):1897–1899

    CAS  PubMed  Google Scholar 

  12. 12.

    Villota VA, Delgado J, Pachajoa H (2014) Congenital varicella syndrome in a monochorionic diamniotic twin pregnancy. J Res Med Sci 19(5):474–476

    PubMed  PubMed Central  Google Scholar 

  13. 13.

    Hagemann G et al (2006) Multiple reversible MR signal changes caused by Epstein-Barr virus encephalitis. AJNR Am J Neuroradiol 27(7):1447–1449

    CAS  PubMed  Google Scholar 

  14. 14.

    Shian WJ, Chi CS (1996) Epstein-Barr virus encephalitis and encephalomyelitis: MR findings. Pediatr Radiol 26(9):690–693

    CAS  Article  PubMed  Google Scholar 

  15. 15.

    Fink KR et al (2010) Neuroimaging of pediatric central nervous system cytomegalovirus infection. Radiographics 30(7):1779–1796

    Article  PubMed  Google Scholar 

  16. 16.

    Hayward JC et al (1991) Lissencephaly-pachygyria associated with congenital cytomegalovirus infection. J Child Neurol 6(2):109–114

    CAS  Article  PubMed  Google Scholar 

  17. 17.

    van der Knaap MS et al (2004) Pattern of white matter abnormalities at MR imaging: use of polymerase chain reaction testing of Guthrie cards to link pattern with congenital cytomegalovirus infection. Radiology 230(2):529–536

    Article  PubMed  Google Scholar 

  18. 18.

    Gorniak RJ et al (2006) MR imaging of human herpesvirus-6-associated encephalitis in 4 patients with anterograde amnesia after allogeneic hematopoietic stem-cell transplantation. AJNR Am J Neuroradiol 27(4):887–891

    CAS  PubMed  Google Scholar 

  19. 19.

    Oki J et al (1995) Serial neuroimages of acute necrotizing encephalopathy associated with human herpesvirus 6 infection. Brain Dev 17(5):356–359

    CAS  Article  PubMed  Google Scholar 

  20. 20.

    Norrby E, Kristensson K (1997) Measles virus in the brain. Brain Res Bull 44(3):213–220

    CAS  Article  PubMed  Google Scholar 

  21. 21.

    Bennetto L, Scolding N (2004) Inflammatory/post-infectious encephalomyelitis. J Neurol Neurosurg Psychiatry 75(Suppl 1):i22–i28

    Article  PubMed  PubMed Central  Google Scholar 

  22. 22.

    Moench TR et al (1988) Acute measles in patients with and without neurological involvement: distribution of measles virus antigen and RNA. J Infect Dis 158(2):433–442

    CAS  Article  PubMed  Google Scholar 

  23. 23.

    Lee KY et al (2003) Acute encephalitis associated with measles: MRI features. Neuroradiology 45(2):100–106

    CAS  Article  PubMed  Google Scholar 

  24. 24.

    Lee YJ (2011) Acute disseminated encephalomyelitis in children: differential diagnosis from multiple sclerosis on the basis of clinical course. Korean J Pediatr 54(6):234–240

    Article  PubMed  PubMed Central  Google Scholar 

  25. 25.

    Buchanan R, Bonthius DJ (2012) Measles virus and associated central nervous system sequelae. Semin Pediatr Neurol 19(3):107–114

    Article  PubMed  Google Scholar 

  26. 26.

    Brismar J et al (1996) Subacute sclerosing panencephalitis: evaluation with CT and MR. AJNR Am J Neuroradiol 17(4):761–772

    CAS  PubMed  Google Scholar 

  27. 27.

    Prashanth LK et al (2006) Adult onset subacute sclerosing panencephalitis: clinical profile of 39 patients from a tertiary care centre. J Neurol Neurosurg Psychiatry 77(5):630–633

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  28. 28.

    Greenfield JG (1950) Encephalitis and encephalomyelitis in England and Wales during the last decade. Brain 73(2):141–166

    CAS  Article  PubMed  Google Scholar 

  29. 29.

    Alkan A et al (2003) Early- and late-state subacute sclerosing panencephalitis: chemical shift imaging and single-voxel MR spectroscopy. AJNR Am J Neuroradiol 24(3):501–506

    PubMed  Google Scholar 

  30. 30.

    Suga K et al (2015) Mumps encephalitis with akinesia and mutism. Pediatr Int 57(4):721–724

    Article  PubMed  Google Scholar 

  31. 31.

    Aydemir C et al (2009) Acute tetraventricular hydrocephalus caused by mumps meningoencephalitis in a child. Pediatr Neurosurg 45(6):419–421

    Article  PubMed  Google Scholar 

  32. 32.

    Takanashi J et al (2015) Clinically mild encephalitis with a reversible splenial lesion (MERS) after mumps vaccination. J Neurol Sci 349(1-2):226–228

    Article  PubMed  Google Scholar 

  33. 33.

    Mizushima N, Murakami Y (1986) Deafness following mumps: the possible pathogenesis and incidence of deafness. Auris Nasus Larynx 13(Suppl 1):S55–S57

    Article  PubMed  Google Scholar 

  34. 34.

    Abe T et al (1998) Japanese encephalitis. J Magn Reson Imaging 8(4):755–761

    CAS  Article  PubMed  Google Scholar 

  35. 35.

    Handique SK et al (2006) Temporal lobe involvement in Japanese encephalitis: problems in differential diagnosis. AJNR Am J Neuroradiol 27(5):1027–1031

    CAS  PubMed  Google Scholar 

  36. 36.

    Singh P et al (2001) Coexistent neurocysticercosis and Japanese B encephalitis: MR imaging correlation. AJNR Am J Neuroradiol 22(6):1131–1136

    CAS  PubMed  Google Scholar 

  37. 37.

    Azad R et al (2003) Is neurocysticercosis a risk factor in coexistent intracranial disease? An MRI based study. J Neurol Neurosurg Psychiatry 74(3):359–361

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  38. 38.

    Petropoulou KA et al (2005) West Nile virus meningoencephalitis: MR imaging findings. AJNR Am J Neuroradiol 26(8):1986–1995

    PubMed  Google Scholar 

  39. 39.

    Ali M et al (2005) West Nile virus infection: MR imaging findings in the nervous system. AJNR Am J Neuroradiol 26(2):289–297

    PubMed  Google Scholar 

  40. 40.

    Nouranifar RK, Ali M, Nath J (2003) The earliest manifestation of focal encephalitis on diffusion-weighted MRI. Clin Imaging 27(5):316–320

    Article  PubMed  Google Scholar 

  41. 41.

    Leis AA et al (2002) A poliomyelitis-like syndrome from West Nile virus infection. N Engl J Med 347(16):1279–1280

    Article  PubMed  Google Scholar 

  42. 42.

    Cerna F et al (1999) St. Louis encephalitis and the substantia nigra: MR imaging evaluation. AJNR Am J Neuroradiol 20(7):1281–1283

    CAS  PubMed  Google Scholar 

  43. 43.

    Wasay M et al (2000) St Louis encephalitis: a review of 11 cases in a 1995 Dallas, Tex, epidemic. Arch Neurol 57(1):114–118

    CAS  Article  PubMed  Google Scholar 

  44. 44.

    Borawake K et al (2011) Dengue encephalitis. Indian J Crit Care Med 15(3):190–193

    Article  PubMed  PubMed Central  Google Scholar 

  45. 45.

    Puccioni-Sohler M, Rosadas C, Cabral-Castro MJ (2013) Neurological complications in dengue infection: a review for clinical practice. Arq Neuropsiquiatr 71(9b):667–671

    Article  PubMed  Google Scholar 

  46. 46.

    Saito N et al (2015) A case of clinically mild encephalitis/encephalopathy with a reversible splenial lesion due to dengue fever. Kansenshogaku Zasshi 89(4):465–469

    PubMed  Google Scholar 

  47. 47.

    Gerardin P et al (2016) Chikungunya virus-associated encephalitis: a cohort study on La Reunion Island, 2005–2009. Neurology 86(1):94–102

    CAS  Article  PubMed  Google Scholar 

  48. 48.

    Ganesan K et al (2008) Chikungunya encephalomyeloradiculitis: report of 2 cases with neuroimaging and 1 case with autopsy findings. AJNR Am J Neuroradiol 29(9):1636–1637

    CAS  Article  PubMed  Google Scholar 

  49. 49.

    Gauri LA et al (2012) Post chikungunya brain stem encephalitis. J Assoc Physicians India 60:68–70

    CAS  PubMed  Google Scholar 

  50. 50.

    Shu B et al (2011) Design and performance of the CDC real-time reverse transcriptase PCR swine flu panel for detection of 2009 A (H1N1) pandemic influenza virus. J Clin Microbiol 49(7):2614–2619

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  51. 51.

    Incecik F et al (2012) Fatal encephalitis associated with novel influenza A (H1N1) virus infection in a child. Neurol Sci 33(3):677–679

    Article  PubMed  Google Scholar 

  52. 52.

    Zeng H et al (2013) Clinical and MRI features of neurological complications after influenza A (H1N1) infection in critically ill children. Pediatr Radiol 43(9):1182–1189

    Article  PubMed  Google Scholar 

  53. 53.

    de Fatima Vasco Aragao M et al (2016) Clinical features and neuroimaging (CT and MRI) findings in presumed Zika virus related congenital infection and microcephaly: retrospective case series study. BMJ 353:i1901

    Article  PubMed  PubMed Central  Google Scholar 

  54. 54.

    Mlakar J et al (2016) Zika virus associated with microcephaly. N Engl J Med 374(10):951–958

    CAS  Article  PubMed  Google Scholar 

  55. 55.

    Awasthi M et al (2001) Imaging findings in rabies encephalitis. AJNR Am J Neuroradiol 22(4):677–680

    CAS  PubMed  Google Scholar 

  56. 56.

    Mani J et al (2003) Magnetic resonance imaging in rabies. Postgrad Med J 79(932):352–354

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  57. 57.

    Lu A et al (2015) Temporal evolution on MRI of successful treatment of rabies. Clin Imaging 39(5):893–896

    Article  PubMed  Google Scholar 

  58. 58.

    Lim CC et al (2002) Nipah virus encephalitis: serial MR study of an emerging disease. Radiology 222(1):219–226

    Article  PubMed  Google Scholar 

  59. 59.

    Wong KT et al (2002) Nipah virus infection: pathology and pathogenesis of an emerging paramyxoviral zoonosis. Am J Pathol 161(6):2153–2167

    Article  PubMed  PubMed Central  Google Scholar 

  60. 60.

    Hautala T et al (2011) Young male patients are at elevated risk of developing serious central nervous system complications during acute Puumala hantavirus infection. BMC Infect Dis 11:217

    Article  PubMed  PubMed Central  Google Scholar 

  61. 61.

    Haddad J et al (1990) Neonatal echovirus encephalitis with white matter necrosis. Neuropediatrics 21(4):215–217

    CAS  Article  PubMed  Google Scholar 

  62. 62.

    Shen WC et al (1999) MR imaging findings of enteroviral encephaloymelitis: an outbreak in Taiwan. AJNR Am J Neuroradiol 20(10):1889–1895

    CAS  PubMed  Google Scholar 

  63. 63.

    Huang YC et al (2013) Adenovirus infection associated with central nervous system dysfunction in children. J Clin Virol 57(4):300–304

    Article  PubMed  Google Scholar 

  64. 64.

    Zagardo MT et al (1998) Rhombencephalitis caused by adenovirus: MR imaging appearance. AJNR Am J Neuroradiol 19(10):1901–1903

    CAS  PubMed  Google Scholar 

  65. 65.

    Nagasawa H et al (2006) A case of non-herpetic acute limbic encephalitis associated with a type-2 adenovirus infection. Rinsho Shinkeigaku 46(5):322–327

    PubMed  Google Scholar 

  66. 66.

    Hibino M et al (2014) Transient hemiparesis and hemianesthesia in an atypical case of adult-onset clinically mild encephalitis/ encephalopathy with a reversible splenial lesion associated with adenovirus infection. Intern Med 53(11):1183–1185

    Article  PubMed  Google Scholar 

  67. 67.

    Takanashi J et al (2010) Clinical and radiological features of rotavirus cerebellitis. AJNR Am J Neuroradiol 31(9):1591–1595

    CAS  Article  PubMed  Google Scholar 

  68. 68.

    Barre-Sinoussi F et al (1983) Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS). Science 220(4599):868–871

    CAS  Article  PubMed  Google Scholar 

  69. 69.

    Smith AB, Smirniotopoulos JG, Rushing EJ (2008) From the archives of the AFIP: central nervous system infections associated with human immunodeficiency virus infection: radiologic-pathologic correlation. Radiographics 28(7):2033–2058

    Article  PubMed  Google Scholar 

  70. 70.

    Filippi CG et al (2001) Diffusion tensor imaging of patients with HIV and normal-appearing white matter on MR images of the brain. AJNR Am J Neuroradiol 22(2):277–283

    CAS  PubMed  Google Scholar 

  71. 71.

    Patel SH et al (2003) Whole-brain N-acetylaspartate level and cognitive performance in HIV infection. AJNR Am J Neuroradiol 24(8):1587–1591

    PubMed  Google Scholar 

  72. 72.

    Dore GJ et al (2003) Marked improvement in survival following AIDS dementia complex in the era of highly active antiretroviral therapy. Aids 17(10):1539–1545

    Article  PubMed  Google Scholar 

  73. 73.

    Padgett BL et al (1971) Cultivation of papova-like virus from human brain with progressive multifocal leucoencephalopathy. Lancet 1(7712):1257–1260

    CAS  Article  PubMed  Google Scholar 

  74. 74.

    Astrom KE, Mancall EL, Richardson EP Jr (1958) Progressive multifocal leuko-encephalopathy; a hitherto unrecognized complication of chronic lymphatic leukaemia and Hodgkin’s disease. Brain 81(1):93–111

    CAS  Article  PubMed  Google Scholar 

  75. 75.

    Hartman EA, Huang D (2008) Update on PML: lessons from the HIV uninfected and new insights in pathogenesis and treatment. Curr HIV/AIDS Rep 5(3):112–119

    Article  PubMed  Google Scholar 

  76. 76.

    Bag AK et al (2010) JC virus infection of the brain. AJNR Am J Neuroradiol 31(9):1564–1576

    CAS  Article  PubMed  Google Scholar 

  77. 77.

    Khanna N et al (2009) Incidence and outcome of progressive multifocal leukoencephalopathy over 20 years of the Swiss HIV Cohort Study. Clin Infect Dis 48(10):1459–1466

    Article  PubMed  Google Scholar 

  78. 78.

    Whiteman ML et al (1993) Progressive multifocal leukoencephalopathy in 47 HIV-seropositive patients: neuroimaging with clinical and pathologic correlation. Radiology 187(1):233–240

    CAS  Article  PubMed  Google Scholar 

  79. 79.

    Bergui M et al (2004) Progressive multifocal leukoencephalopathy: diffusion-weighted imaging and pathological correlations. Neuroradiology 46(1):22–25

    CAS  Article  PubMed  Google Scholar 

  80. 80.

    Katz-Brull R et al (2004) Elevation of myoinositol is associated with disease containment in progressive multifocal leukoencephalopathy. Neurology 63(5):897–900

    CAS  Article  PubMed  Google Scholar 

  81. 81.

    Bienfait HP et al (1998) Progressive multifocal leukoencephalopathy presenting as a solitary gray matter lesion. J Neurol 245(8):557–558

    CAS  Article  PubMed  Google Scholar 

  82. 82.

    Bernal-Cano F, Joseph JT, Koralnik IJ (2007) Spinal cord lesions of progressive multifocal leukoencephalopathy in an acquired immunodeficiency syndrome patient. J Neurovirol 13(5):474–476

    CAS  Article  PubMed  Google Scholar 

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Correspondence to Vijetha Vinod Maller.

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Maller, V.V., Bathla, G., Moritani, T. et al. Imaging in viral infections of the central nervous system: can images speak for an acutely ill brain?. Emerg Radiol 24, 287–300 (2017).

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  • Viral
  • CNS
  • Infection
  • Encephalopathy
  • Myelitis