Histogram Method Based On Routine Magnetic Resonance Images To Explore The Trajectory Of Brain Development In Normal Children Aged 0-5 Years

Objective To investigate the value of histogram method based on routine magnetic resonance images(MRI)in the quantitative evaluation of normal brain development from birth to 5 years of age.Methods The routine brain MRI data(including T1-weighted images(T1WI),T2-weighted images(T2WI)and apparent diffusion coefficient(ADC)maps)of 290 healthy children aged 0-5 years were collected retrospectively in our study.We manually drew the whole brain structure as the region of interest(ROI)at the slice of the anterior and posterior horn of lateral ventricle using MRIcron software,then signal strength histogram and related histogram parameters of these sequences were obtained by the image analysis module based on Python,including mean,maximum value,minimum value,skewness,kurtosis,mode,variance and 10-95%percentile per 5%interval.The parameters that can best describe the trend of brain development were selected by Pearson correlation analysis and exponential function curve regression,and the linear regression coefficient b was used to represent the rate of development at different phases.Independent-sample t test or MannWhitney U test was done to compare the gender differences of parameters in the same group.Results The ADC 10th～70th and ADC mean were highly correlated with age(|r|≥0.70),the T1WI 65th～85th were highly correlated with age(|r|≥0.60),and the T2WI 10th～35th were highly correlated with age(| r |≥ 0.7).The goodness of fit(R2)of the exponential function curve of ADC 30th(R2=0.8900)and T2WI 10th(R2=0.8744)was significantly higher than that of T1WI 80th(R2=0.4205).ADC 30th and T2WI 10th decreased exponentially with the increase of age;ADC 30th changed rapidly before 2 years old,decreased most obviously within 6 months,and decreased slowly after 2 years old,while T2WI 10th decreased rapidly within 1 year old and slowed down after 1 year old.There was no significant gender difference in all groups of ADC 30th(p>0.05),but there was significant gender difference in T2WI 10th between 1～2 years old group and 3～4 years old group(p<0.05).And there was no significant gender difference in remaining groups of T2WI 10th(p>0.05).Conclusions It is feasible to quantitatively analyze the age-related normal brain changes from birth to 5 years of age using histogram method based on routine brain MRI.The growth curve of brain development in this period was well described in the relevant histogram parameters of T2WI and ADC map,which would provide objective reference values for evaluating the normal or abnormal brain development of children based on routine MRI using histogram method in the future.