MR imaging of neonatal brain infections: Germ and specific signs

Transcription

1 MR imaging of neonatal brain infections: Germ and specific signs Poster No.: C-1646 Congress: ECR 2016 Type: Educational Exhibit Authors: N. Mama 1, A. Cherif 1, Y. BEN CHEIKH 2, A. Berrich 1, M. Gaha 1, K. Keywords: DOI: Tlili 1 ; 1 SOUSSE/TN, 2 Nimes/FR Infection, Acute, Surgery, MR-Diffusion/Perfusion, MR, Neuroradiology brain /ecr2016/C-1646 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 26

2 Learning objectives To discuss imaging features of neonatal brain infections depending in the infective agent To review the imaging features of complicated meningitis in infants and neonates Background Perinatal nervous system (CNS) infections are an important cause of mortality and morbidity in neonatal period, and long-term sequelae. Many pathogens: bacteria, viruses, fungi, or parasites can lead to infections frequently involving the CNS, with possible disruption of brain development, Infections of the brain in the neonatal period differ considerably from infections in the older child, due to a variety of age-specific factors that are related not only to the child, but also to the mother, and to specific pathogenic organisms. The late sequels of CNS insult vary with the amount and virulence of the pathogen agent, the timing of infection in relation to the degree of cerebral maturation, the amount of immunologic protection transmitted from the mother the ability of the neonate's immune and inflammatory system to respond to the infection. The mechanism of infection and damage is different among the infectious agents, leading to more specific pathologic findings. Neuroimaging: Neuroimaging patterns are non specific. imaging modalities include : - Transfontanellar ultrasound: primary imaging modality which allows good visualisation of cerebral parenchymal structures and ventricular system. - MR imaging : Page 2 of 26

3 depicts better white matter and cortical edematous or ischemic changes, delivers a complete assessement of the ventrcular and extra cerebral spaces assesses posterior fossa and brainstem lesions gives supplementary informations :contrast enhancement, demostrating tissue viability and metabolic processes by diffusion weighted imaging and MR spectroscopy Findings and procedure details 1. Bacterial infections Epidemiology Most common microorganisms: -streptocoque B -E coli -staphylococus Risk factors: -Prematurity -Chorioamniotitis -Prolonged rupture of fetal membranes -Lack of protection by maternel Ig G the more the onset of the infection is early, the more the infection is serious Physiopathology Extensive vascular inflammation # Obstruction of small and large vessels # Bacteria cross hematoencephalic barrier Page 3 of 26

4 # Plexitis and ventriculitis # Arachnoiditis # Hydrocephalus and parechymal lesions Neuroimaging Acute Phase: -leptomeningeal enhancement -cortical/ sub cortical lesions Complications: -arterial infarcts Fig. 1 on page 7 Fig. 2 on page 8 -vein thrombosis Fig. 3 on page 9 - sub dural sterile collections -empyema Fig. 5 on page 11 Fig. 11 on page 16Fig. 12 on page 17Fig. 13 on page 18 -abcess case 1: streptococcus menigitis with arterial infarcts and vein thrombosis Fig. 1 on page 7 Fig. 2 on page 8 Fig. 3 on page 9 Fig. 4 on page 10 Fig. 5 on page 11 case 2: streptococcus menigitis in a neonate: pseudolaminar necrosis. 6months followup: pseudolaminar necrosis Fig. 6 on page 12 Fig. 7 on page 20Fig. 8 on page 13Fig. 9 on page month follow-up: frontal atrophyfig. 6 on page 12Fig. 10 on page 15 Page 4 of 26

5 Patterns of complications according to germs Streptoccus meningitis : -infarcts -basal ganglia involvement -extra-axial collection without restriction of diffusion E coli meningitis: Extra axial collections with restriction of diffusion Ventriculitis and ventriculomegaly Fig. 11 on page 16 Fig. 12 on page 17 Fig. 13 on page 18 Meningococcus meningitis Sub dural collections with restriction of diffusion Occipital cortical gyral enhancement Serratia infection : Multiple abcesses 2. viral infections Epidemiology: - Enterovirus - HSV1/HSV2 - Echovirus - Human parechovirus 3 Transmission : Page 5 of 26

6 -Transplacentar (3rd T) -During labor -After delivery Outcome: -Atrophy / microcephaly -Epilepsy -Paralysis - Mental impairement HSV méningoencephalitis Vertical transmission in 85% Different pattern from adults : periventricular and deep white matter involvement Sparing temporal and frontal lobes Hemorrhage is rare Restricted diffusion - Outcome : Encephalmalacia and cortical and sub cortical atrophy HSV1: few sequelae HSV2: microcephaly and seizures Human parechovirus Most common virus causing central nervous system infections in UK and USA in newborns and infants less than 90 days - Sepsis and seizures MRI : - Involvement of deep white and sub cortical matter - Corpus callosum Page 6 of 26

7 -Thalamus Sequelae: # Cognitive impairement and epilepsy Enterovirus meningoencephalitis : characteristic feature: symmetrical involvement : - - posterior brainstem - - anterior horns of meddular gray matter less specific: supra tentorial white matter Fig. 14 on page 20 Fig. 15 on page 21 Fig. 16 on page 22 Fig. 17 on page 24 Images for this section: Page 7 of 26

8 Fig. 1: periventricular puntuate infarcts with high signal intensity on DWI Page 8 of 26

9 Fig. 2: periventricular puntuate infarcts with high signal intensity on DWI Page 9 of 26

10 Fig. 3: cortical vein thrombosis complicating bacterial meningitis Page 10 of 26

11 Fig. 4: Sub dural bifrontal collections Page 11 of 26

12 Fig. 5: Subdural bifrontal collections with restricted diffusion: empyema Page 12 of 26

13 Fig. 6: diffuse high signal intensity of the cortex Page 13 of 26

14 Fig. 8: Leptomeningeal enhancement Page 14 of 26

15 Fig. 9: Diffuse restriction of the diffusion: pseudo laminar necrosis Page 15 of 26

16 Fig. 10: 6 months MRI follow up: bi frontal atrophy Page 16 of 26

17 Fig. 11: Triventricular hydrocephaly with leptomeningeal enhancement Page 17 of 26

18 Fig. 12: same case: extra axial retrocerebellar collections Page 18 of 26

19 Fig. 13: ventriculomegaly and sub dural retrocerebellar empyema Page 19 of 26

20 Fig. 7: diffuse cortical abnormalities on axial T1 weighted image. hemorrhage is present in left parietal cortex Page 20 of 26

21 Fig. 14: Newborn with enterovirus menningoencephalitis:axialflair Weighted image: Symmetrical sub cortical white matter involvement W Page 21 of 26

22 Fig. 15: Newborn with enterovirus menningoencephalitis:coronal post-contrast weighted image: continous leptomeningeal enhancement Page 22 of 26

23 Fig. 16: Newborn with enterovirus menningoencephalitis:axial diffusion weighted image: Involved areas are with high signal on diffusion and low signal on ADC map Page 23 of 26

24 Fig. 17: Newborn with enterovirus menningoencephalitis:axial diffusion weighted image: Involved areas are with high signal on diffusion and low signal on ADC map Page 24 of 26

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26 Conclusion Besides delivering a complete anatomic coverage of the brain, MR imaging gives in CNS infections supplementary information by demonstrating contrast enhancement in inflammatory areas, or on tissue viability and metabolic processes by the use of diffusion weighted imaging (DWI) and MR spectroscopy. Although overlap was present, each organism responsible for neonatal/infant meningitis/meningoencephalitis produces an identifiable pattern of complications on MRI. Recognizing these patterns can help the radiologist suggest possible diagnosis and influence early management. Personal information References 1- MR Imaging of Neonatal Brain Infections. JF. Schneider, S Hanquinet, M Severino, A Rossi Magn Reson Imaging Clin N Am 19 (2011) Patterns of complications of neonatal and infant meningitis on MRI by organism:a 10 year review J L. Jaremko, A S. Moon, S Kumbla. European Journal of Radiology 80 (2011) The role of diffusion-weighted echo planar MRI in central nervous system infections regarding etiopathogeneses. Y K#ro#lu, N Karabulut, A Alkan. Diagn Interv Radiol 2010; 16: Human Parechovirus 3 The Most Common Viral Cause of Meningoencephalitis in Young Infants. C Renaud, C J. Harrison. Infect Dis Clin N Am - (2015) 5- Brain Magnetic Resonance Imaging of Infants with Bacterial Meningitis. CR. Oliveira, M C Morriss, JG. Mistrot, J B. Cantey, CD. Doern, P J. Sanchez. J Pediatr Characteristics and outcomes of human parechovirus infection in infants ( ). S Vergnano, S Kadambari, K Whalley, E N Menson, N Martinez-Alier, M Cooper, E Sanchez, P T Heath, H Lyall. Eur J Pediatr. DOI /s Page 26 of 26