| ObjectiveTo investigate the value of ultrasound dual-modality imaging combined with dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)for the assessment of early hepatic fibrosis(HF)in rats,with a view to providing a theoretical basis for the imaging assessment of hepatic fibrosis.MethodsForty-eight healthy female Sprague-Dawley(SD)rats were selected,coded separately and randomly divided into four groups by lottery: control group,M1 group,M2 group and M3 group,12 rats in each group.The control group drank water normally.Model groups: M1 group(ultrasound inspection group),M2group(magnetic resonance inspection group),M3 group(joint imaging inspection group)were induced by CCl4 plus ethanol compound method in rats to prepare liver fibrosis model.CCl4 oil solution was injected intraperitoneally,Twice a week,and the modeling time was 8 weeks in total.The rats in the M1 group underwent ultrasound tests at weeks 4,6 and 8,respectively.The rats’ liver morphology,parenchymal echogenic changes,portal vein travel,measurement of portal vein internal diameter,color doppler observation of portal vein blood flow,and spectral doppler measurement of portal vein flow velocity were observed by 2D sonography,followed by ultrasound elastography to observe the color changes of rat liver parenchymal stiffness and measurement of elasticity values.The M2 group rats were subjected to MRI at weeks 4,6,and 8 to observe the morphological changes of the liver;subsequently,gadoxetic acid disodium injection(Gd-EOB-DTPA)was injected through the tail vein to observe the whole process of liver parenchyma and portal vein development,and the images were stored.The DCE-MRI data were processed with a multifunctional post-processing workstation to observe the volume transfer constant(Ktrans),the rate constant(Kep),the extravascular extracellular volume fraction(Ve),andinitial area under curve(i AUC).The rats in the M3 group were examined by combined imaging techniques at the 4th,6th and 8th weeks,and the examination methods and indexes obtained were the same as those in the M1 and M2 groups.After the imaging examination,the liver tissues were fixed and stained with HE,and the pathological changes were observed under light microscope.Finally,the diagnostic results such as sensitivity,specificity,accuracy,positive predictive value and negative predictive value of each group were compared to evaluate the diagnostic value of different imaging modalities.ResultsThe results of routine ultrasound of rats in group M1 showed that there were no abnormal changes in the liver of control rats,and the morphology of the liver of rats in group M1 changed: the lower margin angle of the liver was slightly blunt and the inner diameter of the portal vein did not change significantly after 4weeks of modeling;the lower margin angle of the liver was blunt and round,the envelope was not smooth,and the inner diameter of the portal vein was slightly widened after 6 weeks of modeling;the morphology of the liver of rats at 8weeks of modeling was full,the envelope was wavy,the margin angle was round and blunt,and the inner diameter of the portal vein was widened and The flow rate was slowed down.Ultrasound elastography showed that the liver elasticity values of rats in the M1 group increased with the increase of fibrosis compared with the control group(P<0.05),in which the liver elasticity values were significantly higher at 4 weeks of modeling compared with the control group,mildly higher at 6 weeks of modeling compared with 4 weeks of modeling,and significantly higher at 8 weeks of modeling compared with 6 weeks of modeling.The results of conventional MRI in the M2 group showed that the liver morphology of the control rats was normal,and in the M2 group,the liver morphology of the rats did not change significantly at 4 weeks of modeling;the liver morphology of the rats was full at 6 weeks of modeling;the ratio of the right and left lobes of the liver was significantly disproportionate in the rats at 8 weeks of modeling.DCE-MRI results:The indicators were analyzed by ROC curve,which showed that Ktrans and Ve had higher diagnostic efficacy for liver fibrosis.The three groups of rats were compared between groups,and the results showed that the sensitivity,accuracy,positive predictive value,and negative predictive value of applying ultrasound bimodality combined with DCE-MRI for the diagnosis of early hepatic fibrosis in rats were higher than their respective individual means of examination.The HE staining results showed that the liver tissues of the control rats were normal,and the liver tissues of the model rats showed different degrees of fibrous hyperplasia.ConclusionAmong the noninvasive diagnostic techniques to assess early liver fibrosis,ultrasound dual-modality imaging techniques combined with dynamic enhancement MRI can effectively improve the ability to assess the severity of liver fibrosis and can be used as an effective test to evaluate liver fibrosis. |
PDF Full Text Request