A Preliminary Study Of Magnetic Resonance Diffusion Tensor Imaging In Normal Kidneys Of Children

Objective: To analyze the characteristics and feasibility of 3.0T diffusion tensor imaging parameters fractional anisotropy(FA)and average diffusion coefficient(ADC)in normal kidneys of children,so as to lay a foundation for further diffusion tensor imaging(DTI)sequencing in the scientific research and clinical application of children kidney diseases.Materials and methods:1.After approval of the ethics committee of University of South China Academy of Pediatrics,a total of 144 cases of normal kidney of children between the ages of 2-14 were collected,male 72 cases,female 72 cases,the average age of 7.6 years.The subjects were divided into groups according to age,weight and height,respectively.All subjects before the examination,fasting and water prohibition,if the subjects can't match,will be to chloral hydrate sedation(0.5ml/kg),dosage of 0.5ml/kg.All subjects were scanned by Siemens Skyra 3.0T magnetic resonance using body coil 18 channel,and the local mean field,and were performed routine MRI and DTI scanning,routine scanning sequence including axial T1WI?T2WI-Fat saturation and coronal T2 WI sequence.2.After 2 radiology experts to evaluate the quality of collected all the DTI image,using Siemens Neuro 3D workstation,the fractional anisotropy and average diffusion coefficient of bilateral renal cortex and medulla were obtained,and diffusion tractography was performed.3.Region of interest(ROI): On the FA gray map of all subjects were measured by two trained doctors,were outlined in the cortex and medulla respectively area in the renal hilum coronal maximum layer and two adjacent layers after or before it,and measured the ADC and FA values of the cortex and medulla respectively,and then calculated the average value of FA and ADC obtained by two doctors.4.Statistical analysis of all data with SPSS20.0 software,the gender by using independent sample t test;single factor analysis of variance with different age,height and weight groups,and different parts of the medulla of the kidney;The relative parameters of the left and right renal cortex,the medulla and the left and right kidney were measured by paired sample t test.The linear correlation analysis and regression analysis of the age,height,weight and the parameters were carried out,and the two sides were tested for less than 0.05.Result:1.There was no significant difference in FA and ADC between different genders and different parts of the two renal medulla.(P > 0.05).2.The FA and ADC values of renal cortex and medulla in different age,height and weight groups were statistically significant.(P < 0.001).3.The FA and ADC values of bilateral renal cortex and medulla were statistically different(<0.001),and the FA value of medulla was greater than that of cortex,while ADC value was less than that of cortex.4.The normal kidney of children aged 2-14 in addition to the double renal cortex ADC were no significant difference(P =0.231),but the rest were statistically different(P <0.001).5.The main factors affecting the FA value of normal left renal medulla in 2-14 year old children were height,and increased with height;The main factors affecting the remaining FA and ADC values in the renal cortex and medulla are the age,and renal medulla FA,ADC value and renal cortex ADC value increased with age,and cortical FA value decreased with age.6.DTT can display the normal renal medullary tubular microstructures,and they are radially aggregated into vertebroid,the tip pointing to the renal portal,and the basement toward the renal cortex.Conclusion: The FA and ADC values of DTI sequence measurement parameters have some regularity in normal kidneys in children,and can indirectly reflect the changes of physiological metabolism characteristics of children with normal kidney motion of water molecules.Post processing DTT technology can indirectly reflect the renal tubular structure of children,indicating that DTI sequence has potential to become a new technology to detect renal physiology and pathology in children;This study lays the foundation for the further study and clinical application of DTI sequences in children's kidneys.