ABSTRACT
Objective:To explore the value of MR elastography (MRE) and shear wave elastography (SWE) for staging liver fibrosis in a rabbit model.Methods:From March to November 2020, 200 healthy New Zealand white rabbits were randomly divided into control group ( n=40) and liver fibrosis group ( n=160) by random number table method. The volume ratio of CCl 4 and olive oil was 1∶1 to prepare 50% CCl 4 oil solution, and the experimental rabbits in the liver fibrosis group were subcutaneously injected with 50% CCl 4 olive oil solution. It was injected once a week at the dose of 0.1 ml/kg in the first to third weeks, once a week at the dose of 0.2 ml/kg in the 4th to 6th weeks. The dose of 0.1 ml/kg was injected twice a week from week 7 to 16. The control group were subcutaneously injected with an equal dose of normal saline. At the end of the 4th, 8th, 12th, and 16th week, 40 and 10 animals in the liver fibrosis group and the control group were randomly selected by random number table method for MRE and SWE, respectively, to obtain the liver elastic stiffness (LS), which were recorded as LS MRE and LS SWE. After the examination, the experimental rabbits were sacrificed and liver tissue of rabbits were taken for histopathological Scheuer staging, and they were divided into F0-F4 groups. One-way ANOVA was used to evaluate the differences of LS MRE and LS SWE in different stages of liver fibrosis. Spearman correlation was used to analyze the correlation between LS and pathological stages. The receiver operating characteristic curve was used to evaluate the efficacy of LS MRE and LS SWE in diagnosing liver fibrosis staging, and the area under the curve (AUC) was compared using the Z test. Results:Totally 162 rabbits were included, which covered F0 ( n=38), F1 ( n=33), F2 ( n=35), F3 ( n=31) and F4 ( n=25). Significant differences of LS MRE and LS SWE values were found among different stages of liver fibrosis ( F=295.29, 102.40, both P<0.001). LS MRE, LS SWE were both positively correlated with liver fibrosis stage ( r=0.93, 0.81, both P<0.001). The AUC of LS MRE for diagnosing liver fibrosis stages ≥F1, ≥F2, ≥F3, and ≥F4 were 0.955, 0.967, 0.996, and 0.980, respectively; the AUC of LS SWE were 0.856, 0.880, 0.974, and 0.953, respectively. The AUC of liver fibrosis stage ≥ F1, ≥ F2 for LS MRE value were greater than LS SWE value ( Z=2.93, 3.29, P=0.003, 0.001), and the AUC of ≥F3, ≥F4 had no significant differences ( Z=1.58, 1.68, P=0.115, 0.093). Conclusion:Both MRE and SWE can accurately predict the stage of liver fibrosis in experimental rabbits, and MRE is better than SWE in diagnosing early liver fibrosis.
ABSTRACT
Objective:To explore the value of quantitative susceptibility mapping (QSM) in evaluating renal injury in patients with early diabetic nephropathy (DN).Methods:From October 2019 to December 2020, 32 patients with early DN were prospectively enrolled in the Third Affiliated Hospital of Soochow University. According to the estimated glomerular filtration rate (eGFR), they were divided into three groups: DN1 (eGFR≥90 ml·min -1·1.73 m -2, 11 cases), DN2 (60-<90 ml·min -1·1.73 m -2, 11 cases) and DN3 (30-<60 ml·min -1·1.73 m -2, 10 cases). At the same time, 32 normal volunteers were recruited as the control group. Both kidneys were scanned by QSM to measure the susceptibility of renal cortex and medulla. Paired samples t-test was used to compare the differences of the susceptibility between left and right kidneys and between cortex and medulla. One-way analysis of variance was performed to compare the differences of corresponding susceptibility values among different groups, and LSD- t was used for the pairwise comparison. Pearson correlation test was performed between the susceptibility value of the medulla and eGFR. The ROC curve was used to analyze the diagnostic efficacy of QSM parameters in the diagnosis of DN and different degrees of severity of DN. Results:The susceptibility values of bilateral renal medulla in normal volunteers and patients with DN were lower than those of renal cortex (all P<0.001). There was no significant difference in the susceptibility value between left and right renal cortex (all P>0.05). There was significant difference in the susceptibility value between left and right medulla (all P<0.05). There was no significant difference in the susceptibility value of bilateral renal cortex among the control group and the DN1－DN3 groups (both P>0.05). The susceptibility values of left renal medulla in control group, DN1, DN2 and DN3 groups were (-4.46±1.16)×10 -2, (-5.96±0.97)×10 -2, (-7.97±1.25)×10 -2, (-9.58±1.45)×10 -2 ppm, of right renal medulla were (-3.70±0.65)×10 -2, (-5.06±1.28)×10 -2, (-7.33±1.46)×10 -2, (-9.09±2.22)×10 -2 ppm, respectively. The overall difference of the susceptibility value of bilateral renal medulla was statistically significant (both P<0.05), and there were significant differences between each two groups (all P<0.05). The linear positive correlation were found between the susceptibility values of renal medulla and the corresponding eGFR (left kidney r=0.732, P<0.001; right kidney r=0.684, P<0.001). The areas under the ROC curve (AUC) of left and right renal medulla susceptibility value in diagnosis of normal and DN were 0.931 and 0.943, of DN1 and DN (2 and 3) were 0.952 and 0.883, of DN (1 and 2) and DN3 were 0.888 and 0.831, respectively. Conclusion:The susceptibility value of QSM quantitative parameter has a certain value in the staging and differential diagnosis of early DN, among which the susceptibility value of renal medulla has higher diagnostic efficiency.