Presented at the Neonatal Society 2014 Autumn Meeting.
Zhu F1, Warrick C1, Lally PJ1, Pauliah S1, Srinivasan L1, Balraj G2, Cowan F1, Shankaran S3, Thayyil S1
1 Centre for Perinatal Neuroscience, Department of Paediatrics, Imperial College London, UK
2 Calicut Medical College, India
3 Wayne State University, Michigan, USA
Background: Although diffusion tensor imaging (DTI) fractional anisotropy (FA) analysed by tract-based spatial statistics (TBSS) is a robust quantifiable biomarker of cerebral microstructural injury, and correlates with early childhood adverse neurological outcomes after neonatal encephalopathy, (1,2), it requires expert input and is not widely available. Here we compared cranial ultrasound (cUS) imaging with whole brain microstructural injury on DTI analysed by TBSS.
Methods: We recruited consecutive term/near term encephalopathic infants admitted to the neonatal unit at Calicut Medical College, India, over a 3 month period. We performed cUS imaging within the first week after birth, and MR imaging (1.5 Tesla, Siemens Avanto) within 2 weeks of birth. Basal ganglia and white matter abnormalities on cUS were scored (0 – normal, 1 – mild, 2 – moderate, 3 – severe), masked to the clinical data. We performed TBSS as previously described (2). Local ethics approval and informed parental consent were obtained prior to recruitment.
Results: Thirty-three newborn infants were recruited; Sarnat staging: 19 (58%) stage I; 10 (30%) stage II;4 (12%) stage III. Six infants died (4 stage III; 2 stage II) before MR scanning. All 27 survivors had a cUS (mean [SD] age 3 [2.3] days) 24 (89%) of whom had DTI (mean [SD] age 8.8 [1.9] days). Three infants (11%) had moderate basal ganglia/thalami echogenicity (scan days 1, 3 and 5) and 4 infants (15%) had moderate white matter echogenicity (scans on day 1). None had severe injury judged on these early cUS. Reduced white matter FA was associated with moderate basal ganglia injury seen on cUS (29% of white matter voxels) but not with white matter injury.
Conclusion: We found that basal ganglia/thalami injury seen on early cUS was associated with reduced whole brain white matter FA on DTI at 2 weeks of age. This was not the case for WM injury but may be because of early cUS scan acquisition. Nonetheless these data support the role of beside cUS imaging in assessing brain tissue injury after neonatal encephalopathy and deserve further investigation.
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1. Tusor N et al., Pediatr Res 2012;72:63–69
2. Lally PJ et al., PloS One 2014;9(2):e87874