An Experimental Study About The Application Of The QSM Technology Based On UTE Sequence And DECT VIC Imaging In Liver Iron Overload

Objective To investigate the relationship about different iron overload and serum iron metabolism indexes in an iron overload animal modelMethods The rats were intraperitoneal injected with different concentrations(0,25,50,100,200,400,600,800 and 1000mg/g,respectively)of iron-dextran to establish the iron overload model.The concentrations of serum ferritin,transferrin(TRF),total iron binding capacity(TIBC)and hepcidin were detected.The inductively coupled plasma spectrometer(ICP)was used to quantify liver iron concentration(LIC).The correlation of dose,SF,TRF,TIBC and hepcidin with LIC were analyzed.The statistic differences of serum iron metabolism indexes between iron overload group(LIC>1.8mg/g)and normal group were analyzed,as well as each subgroup of liver iron overload(corresponding to the LIC thresholds of 1.8,3.2,7.0,and 15.0mg/g).Results There was a significant positive correlation between dosage of administration and LIC(ρ = 0.91,p < 0.001).There was no statistical significance between SF,TRF,TIBC and hepcidin in iron overload group compared with normal group,so was each iron overload subgroup(p>0.05).The correlation between SF and LIC was moderately positive(ρ = 0.50,p < 0.001),while a weak negative correlation between TRF and LIC(ρ =-0.36,p < 0.001)was observed.There were no correlation between TIBC and Hepcidin with LIC(p>0.05).Conclusion The experimental results of animal model of liver iron overload in this study showed that there were correlated between SF and TRF with liver iron concentration,which was significant in evaluating liver iron concentration,but the accuracy was not very high.TIBC and Hepcidin cannot be used to assess iron overload levels.Objective To evaluate the application value of the third generation DSCT in quantification and grading liver iron concentration(LIC)Methods 63 rats with liver iron overload were established by intraperitoneal injection of iron dextran with different concentration(0,25,50,100,200,400,600,800 and 1000mg/g,respectively).Liver was scanned by different energy parameters(70/150 kvp and 90/150kvp)using the third generation DSCT.Virtual iron concentration(VIC)images were reconstructed according to the three-substance separation algorithm after CT scanning.CT value of the liver was measured on VIC images,while LIC by inductively coupled plasma spectrometer(ICP).The statistics significance and correlation between CT value on 70/150 k Vp and 90/150 k Vp VIC images were analyzed.In addition,the relationship between CT value and ICP-LIC was analyzed.Accuracy and consistency in quantification LIC of two method were analyzed.According to the clinical thresholds of iron overload therapy,the receiver operating characteristic(ROC)curve combined with Youden Index were used to determine the optimal cutoff value of CT value,and the AUC(Area under the ROC curve)was used to assess the efficacy of the grading of liver iron overload(mild,moderate,severe,and extremely severe iron overload thresholds of 1.8,3.2,7.0,and 15.0,respectively).Results For the same LIC,CT value of 70/150 kvp VIC image was higher than that of 90/150kvp(p < 0.001),and the correlation was extremely high(ρ = 0.98,p < 0.001).CT value of the two different energy parameters showed strongly positive linear correlation with LIC.The regression equation slopes were 2.976 and 2.290,respectively,accompany with the same correlation coefficient(Both correlation coefficients were 0.98,p < 0.001).The optimal cutoff value of CT value to grade liver iron overload based on70/150 kvp and 90/150 kvp VIC images were 37.65 Hu vs.16.01 Hu(LIC = 1.8mg/g),41.45 Hu vs.19.64 Hu(LIC = 3.2mg/g),47.05 Hu vs.24.06 Hu(LIC = 7.0mg/g)and 73.40 Hu vs.39.61 Hu(LIC = 15.0mg/g),respectively.The AUC of different iron overload grade was greater than 0.950(p>0.05).Conclusion Both 70/150 k Vp and 90/150 k Vp VIC images of the third-generation DECT could quantify and grade LIC accurately.The diagnostic efficacy of the two methods in quantification LIC were consistent with that of ICP.Objective To evaluate the feasibility and accuracy of the QSM technology based on UTE sequence in quantification and grading of liver iron overloadMethod Model of liver iron overload was established by intraperitoneal injecting different concentrations(0,25,50,100,200,400,600,800 and 1000mg/g,respectively)of iron dextran.After rats killed,liver was dipping in 4% paraformaldehyde for 24 h,the liver was scanned using UTE sequence in an 11.7T MR machine.Liver iron concentration(LIC)was measured by inductively coupled plasma spectrometer(ICP).The QSM image was reconstructed successively by Laplace operator,projection onto dipole fields(PDF)and streaking artifacts reduction(STAR)method.The significance and correlation between magnetic susceptibility value of cross-sectional liver(3 slices)and region of interests(ROI)were analyzed after measurement on QSM image,so did LIC.The optimal cutoff value and diagnostic efficacy of magnetic susceptibility value in grading liver iron overload were analyzed by ROC curve and Youden index.Results The magnetic susceptibility value of cross-sectional liver(3 slices)showed a strong correlation with that of ROI(ρ= 0.95,p < 0.001),even if the average was significant different(p>0.05),and both of them showed strong positive correlation with ICP(N = 63,ρ= 0.89 vs.0.79,p < 0.001).The correlation coefficience increased(N = 59,ρ = 0.96 vs.0.95,p < 0.001)without regard to the 4 samples with poor QSM image quality(LIC≥29.76mg/g).The optimal cutoff value of cross-sectional liver(3 slices)magnetic susceptibility value in grading LIC corresponding to clinical criteria(1.8,3.2,7.0,15.0mg/g)were 0.13,0.23,0.34 and 0.67 ppm,respectively.While the ROI were 0.23,0.41,0.76 and 1.12 ppm,respectively.All of the area under curve was greater than 0.960 accompany with high sensitivity and specificity in grading liver iron overload.Conclusion For liver iron concentration below 29.76mg/g,the QSM technology based on UTE sequence is consistent with the efficacy of ICP in quantification LIC,and is highly accurate for iron overload grading.The QSM technology based on UTE sequence could be used as a new method for liver iron quantification and grading.