الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Hypoxic ischemic encephalopathy (HIE) is a major cause of pediatric mortality and morbidity, with possible long-term neurologic sequel, such as cerebral palsy. With improvements in care of at-risk neonates, more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. The aim of the current study was assessment of the additive role of Magnetic Resonance Spectroscopy (MRS) over conventional MRI in diagnosis and early prediction of pathological motor development in neonates with hypoxic ischemic encephalopathy. The study was carried out on thirty (30) neonates (24 full term and 6 preterm) admitted to NICU in Tanta University Hospitals with manifestations of HIE and staged according to sarnat and sarnat staging. Imaging was done at the age of ranging from 6 to 60 days (median 23 days) including conventional MRI (T1WI, T2WI), MRS (for detection of metabolic decompensation) and DWI which was performed in four cases. Neonates were followed till the age of 1 year and evaluated with the Bayley Scales of Infant and Toddler Development for motor developmental outcome. Ten infants (10/30) were clinically normal while twenty (20/30) had unfavorable outcome; 2 infants died, 12 acquired cerebral palsy and 6 acquired delayed motor development by the end of the first year. Initial conventional MRI showed negative results in more than half of the patients (16/30). The remaining had radiological signs of HIE such as PVL, germinal matrix Hemorrhage, white matter injury, reduced myelination, extensive prominent subarachnoid spaces (encephaloatrophy). MRS was done using multivoxels technique where multiple voxels were placed in regions of interest (ROI); frontal and occipital white matter and deep grey matter (basal ganglia and thalamus) to measure metabolite concentrations and ratios in different brain structures and detects metabolic impairment even if MR images were normal or inconclusive. Two MRS sequences were obtained long TE (144ms) to measure NAA, Cr and Cho concentrations and short TE (35ms) mainly to measure Lac concentration, Lac peak was observed in all studied HIE neonates, decreased NAA and increased Cho peaks were obviously detected in HIE patients. MRS ratios showed significant difference between unfavorable and normal outcome infants. MRS ratios as Lac/Cr, NAA/Cr and NAA/Cho within basal ganglia, thalamus and white matter can significantly differentiate between patients with normal and pathological outcome at 1 year. MRS radiological grading of neonates according to Lac/Cr ratio in to 3 grades (grade I Lac/Cr <0.5, grade II Lac/Cr from >0.5 to 1.5 and grade III >1.5) was able to differentiate neonates as grade III whose the highest Lac/Cr ratio had the most severe MRI lesions and the worst outcome. MRS ratios Lac/Cr, NAA/Cr and NAA/Cho within basal ganglia, thalamus and white matter were statically significant in differentiating mild, moderate and severe cases. Lac/Cr positively correlates with the severity of HIE. Both NAA/Cr and NAA/Cho negatively correlate with the severity of the disease. Ratios cut off values as Lac/Cr above 0.38 and 0.42 in basal ganglia and white matter respectively, NAA/Cr below 0.9 and 0.8 in basal ganglia and occipital white matter respectively and NAA/Cho below 0.29 and 0.31 in basal ganglia and frontal white matter were significantly predictive of pathological outcome. MRS is valuable tool for prediction of outcome of HIE neonates. Its application may enable the earliest possible identification of neonates at risk of neurodevelopmental impairment, thereby ensuring appropriate early intervention and rehabilitation.