| Objective:To explore the variation of DWI signal and ADC values of hepatic abscess and study the influence of Escherichia coli?the common pathogenic bacteria of liver abscess?on it,to lay the foundation for further study of the mechanism of the characteristics of diffusion-weighted imaging in Hepatic Abscess.Method:1.Collection in January 2014 to February 2017 the ninth people's hospital affiliated to Shanghai jiao tong university of 26 hepatic abscess patients were retrospectively analyzed in the study,all had MRI examination in the hospital.18 patients were proved to have hepatic abscess by biopsy guided by ultrasound or CT,8 patients were confirmed by clinical effective anti-infection treatment after follow-up examination to reduce or disappear.Analyze the MRI signal features of lesions,and measure the ADC value of each.2.Take Escherichia coli ATCC25922 from the clinical laboratory of the ninth people's hospital as the strain to culture the Escherichia coli,measuring the OD600nm00nm values of cultured Escherichia coli and the number of live Escherichia coli at different points.Depict the growth curve of the Escherichia coli ATCC 25922 with the OD600nm00nm values.At last,we took all Escherichia coli of different culture time to go for DWI?EPI sequence scanning?scan at the same time,measured their DWI signal intensity?SI?and ADC values,to make analysis of their correlation with the quantity of bacteria.Results:1.There are 32 liver abscesses of the 26 patients.22 cases of single lesion,4cases of multiple lesions;All lesions have higher signal on DWI images and lower ADC values,and the average ADC value is?0.87±0.02?×10-3mm2/s among the 32 lesions,while the average value of normal liver tissue is?1.72±0.04?×10-3mm2/s,there is statistically significant difference between the two?P<0.0001?.With 28 lesions have abnormal high perfusion around the liver parenchyma.Indicating that the liver abscess MRI performance has a certain characteristics,and DWI is of good value for the diagnosis of hepatic abscess.2.When the number of viable E.coli ranged from 0 to8.0×108CFU/ml,the ADC value of the fluid changed from 2.27 to 2.6×10-3mm2/s,r=-0.6205,P=0.0236?<0.05?,?=-0.0021;while the SI of DWI changed from 134.89 to185.23,r=-0.4310,P=0.1415?>0.05?;So there was a linear negative correlation between the ADC value and the number of viable E.coli,while there was no correlation between the SI of DWI and the number of viable E.coli.3.When the OD600nm00nm value of the E.coli at different culture time ranged from 0.028 to 1.349,the ADC value of the fluid changed from 2.27 to 2.6×10-3mm2/s,r=-0.5538,P=0.0496?<0.05?,?=-0.1065;while the SI of DWI changed from 134.89 to 185.23,r=-0.4249,P=0.1479?>0.05?;So there was a linear negative correlation between the ADC value and the OD600nm00nm value of the E.coli at different culture time,and there was no correlation between the SI of DWI and the OD600nm00nm value of the E.coli at different culture time,That is to say ADC value was negatively correlated with the total amount of Escherichia coli,and DWI signal intensity was not significantly correlated with the total amount of Escherichia coliConclusions:1.The liver abscess MRI performance has a certain characteristics,and DWI is of good value for the diagnosis of hepatic abscess.2.In this study,we found that ADC value was negatively correlated with the amount of E.coli and its correlation with viable count was stronger than that of total bacterial.3.There was no significant correlation between DWI signal intensity and E.coli count in this study,which may be related to the effect of various factors on DWI signal intensity. |
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