The value of T1WI signal intensity ratio of globus pallidus to putamen in grading and predicting prognosis of neonatal acute bilirubin encephalopathy

Objective To discuss the T1WI signal intensity ratio of globus pallidus to putamen in neonatal acute bilirubin encephalopathy (ABE) , and its relations with grading and prognosis evaluation in ABE. Methods Eighty-five cases of neonatal acute bilirubin encephalopathy from January 2013 to December 2015 were divided into three groups, including 56 cases of mild group, 19 cases of medium group, 10 cases of severe group depending on the scores of bilirubin induced neurological dysfunction (BIND) and correlated with cranial MRI examination. Sixty-four cases with follow-up for half a year, were divided into good prognosis group (44 cases) and poor prognosis group (20 cases) by Gesell development scales, and 23 patients had cranial MRI examination. Measurements of T1WI signal intensity of globus pallidus and putamen were made, the G/P ratio was calculated, and the day age of children was recorded. The G/P ratio and the day age of light, medium, severe groups using single factor analysis of variance between each other. Good prognosis group, poor prognosis group using homogeneity test of variances and then using independent sample to test for comparative analysis. Analysis of the line of ROC curve of G/P ratio was performed to predict prognosis. Results The G/P ratio of light, medium, severe groups are 1.12±0.05, 1.30±0.09, 1.38±0.05, the difference had statistical significance (F=38.90,P<0.01) .There was no statistical difference in the three groups of day age. The G/P ratio of good prognosis group and poor prognosis group were 1.35±0.08, 1.23±0.05 respectively, the difference had statistical significance (t=-7.48,P<0.01) , The day age of these groups had no statistical difference. Analysis the ROC curve of G/P ratio, area under curve was 0.896, the best threshold was 1.29 and the sensitivity was 85.0% and the specific degreeswas 90.9%. Conclusion The G/P ratio could help clinical evaluation of neonatal ABE for grading. G/P ratio could predict prognosis, a G/P ratio of greater than 1.29 indicated poor prognosis. Key words: Kernicterus; Magnetic resonance imaging; Globus pallidus; Infant, newborn