The Value Of MRI In Acute Bilirubin Encephalopathy Of Neonates

Background In 1904, Schmorl held an autopsy on the remains of one neonate died of severe jaundice and found that the brain basic nuclear was yellow-dyed and named this disease as kernicterus. This yellow-dyed material is identified as unconjugated bilirubin, it can cause toxic disease of neuro-cells, so kenicterus is also called bilirubin encepha-lopathy. Bilirubin encephalopathy is the important complication of neonate pathologic jaundice. It can cause to neuro-system sequelae of different degrees, even to death. Bilirubin encephalopathy is a controllable disease. Hyperbilirubinemia is the important causing condition, but is not the only one. Nowadays, there isn't a generally accepted and objective clinical determination for kernicterus, it can only diagnosed according to clinical characteristics and lab examinations. Shapiro thought although total serum bilirubin (TSB) is important, kernicterus cannot be defined based solely on TSB, and for study purposes kernicterus may be defined in term and near-term infants with TSB≥20 mg/dl using abnormal muscle tone on examination, auditory testing diagnostic of AN/AD, and magnetic resonance imaging showing bilateral lesions of globus pallidus±subthalamic nucleus. Many foreign scholars have researched on MRI, most of them concentrated on the lingering period, less on neonates'period. Previous research thought the MRI high signal intensity in both globus-pallidus is the significance characteristic of kernicterus, but some scholars treated it as normal. So it is hard to differentiate the degree of the high signal intensity in both globus-pallidus, and the previous scholars didn't tell us the standard of the high signal intensity.Objective To explore the relationship between MRI signal intensity in both globus-pallidus and the level of serum bilirubin in neonates for providing the diagnostic evidence of bilirubin encephalopathy.Methods1. Sixty-seven yellow-dyed neonates received cranial MRI examination using Philips Achieva 1.5T MRI scanner with head and neck coil, and they were divided into four groups depending on the levels of total serum bilirubin (TSB).2. MR pulse sequence include transverse T1WI(SE sequence), T2WI (TSE sequence),DWI (EPI/SE sequence),DTI (EPI/SE sequence).3. Two-way Analysis of variance was used to analyse the signal intensity of T1WI and T2WI, the value of EADC, ADC and FA in both globus-pallidus. And then, compare the difference between the real measurements and the results according to the naked eyes.Results1. On naked eye, only five neonate's T1WI signal intensity in both globus-pallidus in groupⅣis higher that the other group's (5/18), however, there are also neonates whose globus-pallidus manifested obvious high signal in T1WI (6/41). There are no differences in T2WI signal intensity in the four groups.2. The value of T1WI signal intensity in grope IV is significantly higher than gropeⅠ,ⅡandⅢ, the difference has statistical significance (P<0.05). The value of T1WI signal intensity in grope III is significantly higher than gropeⅠandⅡ, the difference has statistical significance (P<0.05). There is no obvious difference between gropeⅠandⅡ(P>0.05). There is no obvious difference between the left and right globus-pallidus T1WI signal intensity in the four groups (P> 0.05).Moreover the signal intensity of the neonates whose globus-pallidus looks obvious high signal in T1WI of gropeⅠ,ⅡandⅢis lower than the mean value of groupⅢandⅣ. There is no statistical difference among the four gropes about the signal intensity of T2WI, the value of EADC, ADC, FA (P>0.05).3. The eight neonates with kenicterus according the Shapiro's definition came from gropelV. Five of the eight neonates T1WI signal intensity is higher than the mean value of gropeⅣ, three of them is lower than this mean value, but is higher than the mean value of gropeⅢ.Conclusion1. There is an intimate relationship between the signal intensity in both globus-pallidus on T1WI and the severity of hyperbilirubinemia.2. It is the important characteristic of bilirubin encephalopathy in neonates of T1WI high signal intensity in both globus-pallidus. Observing the signal intensity On naked eyes in both globus-pallidus on T1WI may be disturbed by many factors, and is not objective. The measurement of the signal intensity of T1WI can manifest the changes in both globus-pallidus. globus-pallidus.3. In this article the signal intensity of TIWI in both can be thought high when it exceed 1147±38. According to shapiro's definition, infants with TSB≥20 mg/dl using abnormal muscle tone on examination, auditory testing diagnostic of AN/AD, and high TIWI signal intensity exceeding 1147±38 can be defined as kernicterus.