Cerebral malaria: MR imaging spectrum

Transcription

1 Cerebral malaria: MR imaging spectrum Poster No.: C-2705 Congress: ECR 2010 Type: Educational Exhibit Topic: Neuro Authors: P. S. Naphade, M. D. Agrawal, S. S. Sankhe, K. M. Siva, B. K. Jain; Mumbai/IN Keywords: Cerebral malaria, Postinfectious demyelination, Haemorrhagic infarct DOI: /ecr2010/C-2705 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 25

2 Learning objectives To illustrate the MR imaging spectrum of cerebral malaria To become familiar with the lesion distribution and signal changes on various MR sequences and to correlate with possible pathologic mechanism In this exhibit, we will review the role of MRI in the evaluation of cerebral malaria Background Malaria is widespread disease in tropical countries caused by Plasmodium falciparum.cerebral malaria is most severe complication due to plasmodium falciparum with mortality rate of more than 50%.Neurological complications occur in almost 2% patients. Impaired consciousness, convulsion and coma occur along with high grade fever and chills. The neurological manifestations are non-specific because of diffuse involvement of the brain. The basic pathogenetic mechanism is vascular occlusion by the sequestered parasitized RBCs and immune-mediated inflammatory response with release of vasoactive substances capable of producing endothelial damage and alterations of permeability. The pathological changes in cerebral malaria include cerebral edema, infarcts due to blockage of lenticulostriate vessels by parasitized RBCs, hemorrhagic infarcts due to venous thrombosis, petechial hemorrhages and demyelination. Neuroimaging helps to rule out meningitis, viral encephalitis and venous thrombosis which may mimic cerebral malaria clinically (causes of convulsion and coma in febrile patient) as well as typical imaging features in correct clinical context may establish the diagnosis of cerebral malaria. In this exhibit, we will review the MR imaging spectrum of cerebral malaria Page 2 of 25

3 Imaging findings OR Procedure details Normal scan is the commonest MR imaging finding in cerebral malaria. However MR spectroscopy in basal ganglia consistently shows reduction of NAA.Bilateral symmetric basal ganglia T2 hyperintensity with restricted diffusion is a common finding due to blocking of lenticulostriate vessels by parasites. Page 3 of 25

4 Fig.: Fig.:T2 Axial image shows hyperintense signal in bilateral basal ganglia Page 4 of 25

5 Fig.: Fig.:T2 Axial image shows both the hippocampi to be hyperintense Page 5 of 25

6 Fig.: Fig.: FLAIR Axial image shows hyperintense signal both basal ganglia, thalami and cerebral cortex Page 6 of 25

7 Fig.: Fig.: DWI (Diffusion weighted image) shows restricted diffusion in both basal ganglia Bithalamic involvement is as common as basal ganglia involvement. T2/FLAIR hyerintensity with or without restricted diffusion is the most common abnormality. Hemorrhagic infarct in thalamus, unilateral/bilateral, due to internal cerebral vein thrombosis. Venous infarcts are also seen in cerebral parenchyma due to dural venous thrombosis. Page 7 of 25

8 Fig.: Fig.: T2 Axial image shows hyperintense signal in bilateral basal ganglia with central hypointens due to haemorrhagic infarct Page 8 of 25

9 Fig.: Fig.: FLAIR Axial image shows hyperintense signal in midbrain and deep periventricular white matter Page 9 of 25

10 Fig.: Fig.:T2 Axial image shows hyperintense signal in bilateral globus pallidus Page 10 of 25

11 Fig.: Fig.: FLAIR Axial image shows hyperintense signal in bilateral globus pallidus Page 11 of 25

12 Fig.: Fig.: GRE (Gradient) image shows hypointensity in both globus pallidi s/o haemorrhage Page 12 of 25

13 Fig.: Fig.: DWI (Diffusion weighted image) shows restricted diffusion in both globus pallidi Petechial hemorrhage on gradient echo sequence is a common finding in cerebral malaria. Page 13 of 25

14 Fig.: Fig.: GRE (Gradient) image shows multiple petechial haemorrhages Cerebral cortical thickening and T2/FLAIR hyperintensities due to encephalitis is a common finding. However this cortical thickening does not follow the typical regional (front temporal lobes) involvement. Page 14 of 25

15 Fig.: Fig.: T2 Axial image shows enlargement and hyperintense signal in basal ganglia, thalami and cerebral cortex Page 15 of 25

16 T2 hyperintensities with restricted diffusion in the Centrum semiovale and corona radiate can be seen either due to nonhaemorrhagic infarcts or postinfectious demyelination. Postinfectious demyelination show imcomplete ring enhancement on postcontrast scan and associated T2 hyperintense lesion can be seen in brainstem and cerebellar hemispheres.postinfectious demyelination occurs after treated malaria. Page 16 of 25

17 Fig.: Fig.: FLAIR Coronal image shows hyperintense signal in periventricular white matter and cerebellar white matter in a case of postinfectious demyelination. This patient was diagnosed case of cerebral malaria and presented with sudden onset ataxia Page 17 of 25

18 Fig.: Fig.: FLAIR Coronal image shows hyperintense signal in cerebellar white matter in a case of postinfectious demyelination Page 18 of 25

19 Fig.: Fig.: T2 Coronal image shows hyperintense signal in centrum semiovale, corona radiate and midbrain due to postinfectious demyelination in a case of cerebral malaria Page 19 of 25

20 Fig.: Fig.: T2 Axial image shows hyperintense signal in midbrain due to postinfectious demyelination Page 20 of 25

21 Fig.: Fig.: DWI (Diffusion weighted image) shows restricted diffusion in centrum semiovale Page 21 of 25

22 Fig.: Fig.: DWI (Diffusion weighted image) shows multiple tiny foci restricted diffusion in bilateral centrum semiovale represents lacunar infarcts in a case of cerebral malaria. Postcontrast imaging usually does reveal any abnormal enhancement. However pachymeningitis in a case of clinical diagnosis of cerebral malaria is shown below. Page 22 of 25

23 Fig.: Fig.: Post contrast T1 image shows abnormally increased pachymeningeal enhancement s/o pachymeningitis. Page 23 of 25

24 Conclusion MRI is accurate in diagnosing the ischemic as well as haemorrhagic complications of cerebral malaria. Diffusion weighted images and gradient echo sequences are useful for demonstrating the haemorrhagic infarcts and petechial haemorrhages. Knowing the imaging spectrum, we can establish the diagnosis of cerebral malaria in correct clinical scenario and clinical mimics of cerebral malaria can be excluded. Personal Information P.S. Naphade, M.D. Agrawal, S.S. Sankhe, K.M. Siva, B.K. Jain; Department of Radiology, KEM Hospital, Mumbai ,Maharashtra,India - prashant.nafade@gmail.com References 1.Yves-Se bastien Cordoliani, Jean-Luc Sarrazin, Dominique Felten, Eric Caumes,Christophe Le veˆque, and Alain Fisc; MR of Cerebral Malaria; AJNR Am J Neuroradiol 19: , May C J Das and R Sharma, Central pontine myelinolysis in a case of cerebral malaria; The British Journal of Radiology, 80 (2007), e293-e Sarmistha Gupta, Kailash Patel; Case series: MRI features in cerebral malaria; Indian Journal Radiol Imaging /Aug2008/Vol 18/ Issue 3 Page 24 of 25

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