Application Of Synthetic MRI In Hyperbilirubinemia And Acute Bilirubinopathy

PART 1 Comparison Study of Image Quality between Synthetic MRI and Conventional MRI in Neonatal JaundiceObjective(s): To evaluate the difference of image quality between syMRI(Synthetic magnetic resonance imaging,syMRI)and conMRI(Conventional magnetic resonance imaging)in neonatal jaundice patients.Method(s): Forty-two patients with neonatal jaundice who underwent routine MRI and syMRI in our hospital from May 2020 to August 2021 were retrospectively collected.Sy1 image and sy2 image are reconstructed on syMRI.The parameters of sy1 image are the same as those of conventional images,and the parameters of sy2 image are the default ones of MAGIC sequence(Conventional images are marked as conimages;The composite image is marked as sy image,the composite image 1 is marked as sy1 image,and the composite image 2 is marked as sy2 image).The signal enhancement values of all sequences including gray matter,white matter and cerebrospinal fluid were measured,and the image SNR,relative contrast and relative contrast of lesions were calculated.The overall image quality,anatomical boundary,image artifact and lesion boundary clarity of all sequences were evaluated,and the evaluation standard was 5 points.Paired t test and paired Wilcoxon rank sum test were used,and the difference was statistically significant with a bilateral test of P<0.05.Result(s): The SNR of conT1FLair and conT2WI is generally higher than that of sy image,and the SNR of conT2Flair is higher than that of sy1T2Flair and lower than that of sy2T2Flair,and the difference is statistically significant(P<0.001).The relative contrast of conT1FLair and gray matter/white matter of conT2WI is higher than that of sy1 image,while that of conT1FLair and conT2WI is lower than that of sy2 image,and the difference is statistically significant(P<0.001).The overall quality scores of conT1Flair and conT2Flair were higher than Sy1,and the difference was statistically significant(P<0.001).There was no significant difference in the overall quality scores of conT1Flair,conT2Flair and sy2 images,and conT2WI and sy images(P>0.05).The gray matter differentiation of conT1Flair and conT2WI was lower than that of sy image,and the caudate nucleus and lentiform nucleus of conT1Flair were lower than that of sy2T1Flair,with statistical significance(P<0.05).conT1Flair is lower than sy image in differentiating sulcus,while conT2Flair is higher than sy image,and the difference is statistically significant(P<0.05).The granular artifacts of conT1Flair and conT2Flair are more than sy images,and the granular artifacts of conT2Flair are less than sy images,with statistical significance(P<0.05).The venous sinus high signal of syT1Flair and the brain surface high signal of syT2Flair were more than those of conventional images,and the difference was statistically significant(P<0.05).There was no significant difference in pathological score between conimage and sy image(P>0.05).The relative contrast of globus pallidus/gray matter of conT1Flair is lower than that of sy image,but conT2WI is higher than that of sy image,and conT2Flair is higher than that of sy image,with statistical significance(P<0.001).Conclusion(s): Overall,the image quality of syMRI can be used for clinical diagnosis of neonatal brain,but attention should be paid to the parameter setting of syMRI and the judgment of some image artifacts.Part Ⅱ Study on the Value of Synthetic MRI Quantitative Parameters in Neonatal Bilirubin EncephalopathyObjective(s):To study the value of quantitative parameters of syMRI in the evaluation of neonatal bilirubin encephalopathy.Method(s): A retrospective collection of 53 patients with jaundice in term newborns who underwent syMRI examination in our hospital from May 2020 to August 2021 was conducted.According to TSB level,neonatal hourly bilirubin nomograms made by Bhutani,USA,they were divided into control group(N group)and hyperbilirubinemia group(S group),among which the subgroup of S group was divided into mild group(S1 group)and severe group(S2 group).According to their age,they were divided into A1 group,A2 group and A3 group.According to gestational age,they were divided into B1 group,B2 group and B3 group.Quantitative images were obtained by scanning with syMRI,and the T1,T2 and PD values of globus pallidus(G)and the T1 value of putamen(P)were measured,and the ratio of T1 value of globus pallidus to putamen(T1G/P)was calculated.Single factor analysis of variance was used for comparison among the three groups,and LSD method was used for comparison between the two groups.Pearson and spearman were used to analyze the correlation between groups.Find out the optimal threshold value for diagnosing ABE with T1G/P,T2,and PD values through the ROC curve.There was a statistically significant difference in P<0.05 between the two tests.Result(s): There were significant differences in T2 values between N and S,between N group and S2 group,and between S1 group and S2 group(P<0.05),but there were no significant differences in T2 values,T1G/P and PD values between N group and S1 group(P>0.05).There were significant differences in T2 values between group A1 and A2,and between group A2 and group A3(P<0.05),but there was no significant difference between group A1 and group A3(P>0.05).There were significant differences in PD between group A1 and group A2,and between group A1 and group A3(P<0.05).There was no significant difference in T1G/P,T2 and PD among B1,B2 and B3 groups(P>0.05).There is a moderate positive correlation between T2 value and TSB in group S(r=0.589,P=0.002).There was a negative correlation between PD value and age(r=-0.475,P=0.000).According to ROC curve analysis,the AUC of T2 value is 0.772 and the optimal critical value of T2 value for diagnosing ABE is137.58 ms,with sensitivity of 62.5% and specificity of 86.7%.Conclusion(s):The quantitative parameters of syMRI have certain value for the evaluation of ABE,and the quantitative parameter T2 value of syMRI has reference value for the early diagnosis of ABE.