Neonatal hypoxic-ischemic brain injury imaging: A pictorial review

Transcription

1 Neonatal hypoxic-ischemic brain injury imaging: A pictorial review Poster No.: C-1425 Congress: ECR 2014 Type: Educational Exhibit Authors: E. Alexopoulou 1, A. Mazioti 1, D. K. Filippiadis 2, C. Chrona 1, M. Keywords: DOI: A. Papathanasiou 1, N. L. Kelekis 1 ; 1 Athens/GR, 2 MAROUSI - ATHENS/GR Education and training, Diagnostic procedure, Ultrasound, MR, Pediatric, CNS /ecr2014/C-1425 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 13

2 Learning objectives To become familiar with the imaging findings in neonatal hypoxic-ischemic brain injury in ultrasound and MRI examinations. To understand the different patterns of brain injury in preterm and term neonates. Background Neonatal hypoxic-ischemic brain injury is one of the most common causes of cerebral palsy in children [1]. Clinical manifestations may be low Apgar score at delivery, symptoms of apnea or seizures. Brain ultrasound is the first examination of choice in evaluating these neonates, as it is a cheap and easy examination which can be performed at the bed-side of the baby. However, its sensitivity to abnormalities of the convexities or the brainstem is limited. MRI is the most sensitive and specific imaging modality, with characteristic imaging findings [2]. Findings and procedure details The pattern of brain injury in neonatal hypoxic-ischemic injury depends on the brain maturation and the severity of the insult. Therefore, there are described four different patterns of injury [3, 4]. 1. Mild hypoxia in preterm babies 2. Severe hypoxia in preterm babies 3. Mild hypoxia in term babies 4. Severe hypoxia in term babies 1. Mild hypoxia in preterm neonates In the immature brain the most vulnerable area in mild to moderate asphyxia is the periventricular region, causing periventricular leukomalacia (PVL) and/or hemorrhage. In periventricular leukomalacia ultrasound may be initially normal, but within two weeks there is increased echogenicity in the periventricular white matter, greater than the adjacent choroid plexus and usually bilateral and symmetric. After 2-6 weeks, cysts are formed, which confirm the diagnosis of PVL [3-5] [Figure 1]. Page 2 of 13

3 In MRI, PVL manifests initially as periventricular increased T2-signal intensity. Subsequently there is cyst formation, whereas in end-stage disease there is enlargement of the ventricles with irregular margins, loss of periventricular white matter and gliosis [6,7] [Figure 2]. Reperfusion to the ischemic brain parenchyma in the immature brain can also cause germinal matrix hemorrhage, which is classified as follows [8]: Grade I: subependymal hemorrhage [Figure 3] Grade II: intraventricular hemorrhage without ventricular dilatation Grade III: intraventricular hemorrhage with ventricular dilatation [Figures 4,5] Grade IV: parenchymal venous infarction [Figures 6,7] 2. Severe hypoxia in preterm neonates Severe hypoxia in preterm neonates results in infarction of the deep gray matter, brainstem, and cerebellum, with or without concomitant hemorrhage/ PVL [3,4]. 3. Mild hypoxia in term neonates Mild hypoxia in term neonates causes injury to the intervascular watershed zones, resulting to ischemic infarct. Ultrasound may show an area of increased echogenicity and abnormal RI on Doppler. MRI is more sensitive, as difussion weighted-imaging depicts the ischemic infarct from day 1 [3-7]. Resticted diffusion appears bright on difussion weighted MRI and dark on the apparent difussion coefficient map image (ADC) [Figure 8]. 4. Severe hypoxia in term neonates Severe hypoxia in term neonates causes injury to the basal ganglia, hippocampi, corticospinal tracts, and sensorimotor cortex [3-7][Figure 9]. Images for this section: Page 3 of 13

4 Fig. 1: Figure 1a: Coronal ulrasound in a preterm (30 weeks gestation) shows increased echogenicity of periventricular white matter. Figure 1b: Follow-up ultrasound after two weeks shows some cyst formation on the right (thick arrow). Figure 1c: Follow up at termequivalent (right sagital image)shows mild ventricular dilatation(thin arrow) and extensive cyst formation, findings which confirm the diagnosis of periventricular leukomalacia. Page 4 of 13

5 Fig. 2: Figure 2. Sagittal T2-weighted MRI in a preterm baby (29 weeks gestation), two months after delivery. Extensive periventricular leukomalacia with many periventricular cysts. Methemorrhagic hydrocephalus is also present in this baby, caused by grade III hemorrhage. Page 5 of 13

6 Fig. 3: Figure 3. Coronal (a), right sagital (b) and left sagital (c) ultrasound in a preterm (32 weeks gestation). There is increased echogenicity in the right caudothalamic groove, suggesting grade I hemorrhage (arrows). Note normal echogenicity on the left. Fig. 4: Figure 4. Coronal (a) and right sagittal (b) brain ultrasound in a preterm baby (32 weeks gestation). There is bilateral sybependymal and intraventricular hemorrhage with mild ventricular dilatation, findings consistent with grade III hemorrhage. Page 6 of 13

7 Fig. 5: Figure 5. Coronal brain ultrasound in a preterm baby (30 weeks gestation). There is bilateral sybependymal and intraventricular hemorrhage with mild ventricular dilatation, findings consistent with grade III hemorrhage. Page 7 of 13

8 Fig. 6: Figure 6. Coronal (a, b) and right sagittal (c) brain ultrasound in a preterm baby (30 weeks gestation). There is bilateral sybependymal and intraventricular hemorrhage with mild ventricular dilatation. There is also an additional parenchymal hemorrhagic infarct on the right, findings consistent with grade IV hemorrhage. Figure 6d. Follow up after three weeks shows right ventricular dilatation with abnormal ventricular contour and cyst formation. Page 8 of 13

9 Fig. 7: Figure 7a. Coronal ultrasound in a baby born prematurely due to mother's car accident (32 weeks gestation). There is bilateral sybependymal and intraventricular hemorrhage with mild ventricular dilatation, with concomitant right thalamic hemorrhage (Grade IV). Figures 7b, c and d. Axial (a,b) and right sagital brain T2-weighted MRI, in the same neonate shows the hemorrhage with low signal. Page 9 of 13

10 Fig. 8: Figure 8. Diffusion MRI (a) and ADC map (b) in mild hypoperfusion in a 3- days old term baby. Restricted diffusion consistent with acute ischemic injury in the left intervascular watershed zone between the anterior and middle cerebral artery and the middle and posterior cerebral artery. Page 10 of 13

11 Fig. 9: Figure 9. Diffusion MRI in severe hypoperfusion in a 2-days old term baby. Restricted diffusion concistent with acute ischemic injury in the left sensorimotor cortex. This newborn also had basal ganglia injury (not shown). Page 11 of 13

12 Conclusion Neonatal hypoxic-ischemic brain injury is a major cause of neurologic deficit in children. Knowledge of the different patterns of injury and their imaging findings according brain maturity and severity of hypoxia is essential for all radiologists. Personal information UNIVERSITY OF ATHENS 2 nd DEPARTMENT OF RADIOLOGY E.Alexopoulou, MD As.Professor of Paediatric Radiology Attikon University Hospital 1 Rimini Street, Haidari, Athens, Greece Tel: Mobile: ealex64@hotmail.com References 1. Paneth N, Hong T, Korzeniewski S. The descriptive epidemiology of cerebral palsy. Clinics in Perinatology 2006;33(2): van Wezel-Meijler G, Steggerda SJ, Leijser LM. Cranial ulltrasonography in neonates: role and limitations. Semin Perinatol 2010 Feb;34(1): Chao CP, Zaleski CG, Patton AC. Neonatal hypoxic-ischemic encephalopathy: multimodality imaging findings. Radiographics 2006 Oct;26 Suppl 1:S de Vries LS, Groenendaal F. Patterns of neonatal hypoxic-ischaemic brain injury. Neuroradiology 2010 Jun;52(6): Cassia GS, Faingold R, Bernard C, Sant'Anna GM. Neonatal hypoxicischemic injury:sonography and dynamic color Doppler sonography Page 12 of 13

13 perfusion of the brain and abdomen with pathologic correlation. AJR 2012 Dec;199(6):W Heinz ER, Provenzale JM. Imaging findings in neonatal hypoxia: a practical review. AJR 2009 Jan;192(1): Izbudak I, Grant PE. MR imaging of the term and preterm neonate with diffuse brain injury. Magn Reson Imaging Clin N Am 2011 Nov;19(4): Papile LA, Munsick-Bruno G, Scaefer A. Relationship of cerebral intraventricular hemorrhage and early childhood neurologic handicaps. J Pediatr 1983 Aug;103(2): Page 13 of 13