| Objectives: To investigate the bio-distribution of Gadopentetate dimeglumine in the Abdominal Solid Organs of rats and its effect on Intravoxel Incoherent Motion MRI in the rat kidney.Methods: Thirty normal Wistar rats fed adaptively for ten days were divided into two groups A and B by random number table method,6 rats were randomly grouped into group A,and both IVIM and T1 WI sequences were performed at 24 h pre-injection and at internals of 1h?4?24?48?72h?7day and 10 day post-injection.Magnetic resonance imaging was performed to obtain abdominal axial T1 WI images(including liver and left kidney,muscle)and right kidney coronal IVIM image.Twenty-four rats in group B were randomly sacrificed at each time point of MR examination.Blood was perfused by cardiac perfusion to remove the blood.The liver,spleen,kidney and muscle were removed and stored in-80 ? refrigerator after aliquoting.The concentration of gadolinium in each tissue was measured by ICP-MS.We analyzed the changes of the signal intensity(SI),signal enhancement(E)and every parameter(D,D*,f,ADC)of renal regions of cortex(CO)?outer stripes of the outer medulla(OSOM)?inner stripes of the outer medulla(ISOM)and inner medulla(IM)using one-way repeated measures ANOVA.Result: 1.At 1 h after injection of contrast agent,the content of gadolinium in kidney,liver,spleen and muscle peaked,it was significantly higher in kidney than that in other tissues,liver and spleen,while in muscle was lower.The content of gadolinium in the tissue decreased with time,and decreased most significantly at 4h after injection,which decreased by 24.9%,50.5% and 64.2% respectively,while decreased more stable in the spleen.Ten days after injection,the content of gadolinium in the kidneys was still higher than that in the liver and spleen,but the content of gadolinium was not detected in the muscles.2.The SNR of each tissue increased at 1 hour after injection,but there was no significant difference in SNR at different time points in liver,spleen and muscle(P> 0.05).At 4h,1day,2day,3day and 7day,the SNR value of the kidneys continued to decrease(P<0.05),but the difference was statistically significant(P<0.05).Ten days after the injection,the levels returned to the level before injection,the difference was not statistically significant(P> 0.05).Before and after injection of contrast agent,the ADC value of kidney was greater than D value,the difference was statistically significant(P <0.05).D value and ADC value of CO,OM and IM decreased from 1 h to 24 h after injection of contrast agent,and there was significant difference between D value and ADC value before injection of contrast agent(P <0.05).The value of D and ADC of CO began to rise at 4 hours after injection,and there was no significant difference between baseline and 48 hour(P> 0.05),while the values of D and ADC decreased in the OM and IM recovered at 24 h after injection.However,there was no significant difference in the value of f and D * before and after contrast injection(P> 0.05)Conclusion: 1.The bio-distribution of gadopentetate dimeglumine in the visceral organs of the abdomen was determined by ICP-MS and found to be significantly higher in the kidney than in other organs and tissues(liver,spleen and muscle).Until 10 days after contrast injection,there is still a high concentration of gadolinium in the kidneys.The increase of MR signal has a certain correlation with the concentration of gadolinium.When the concentration of gadolinium in the tissue is high,the enhancement rate of MR signal E can be used to approximate the concentration of gadolinium in the tissue.2.After injection of gadopentetate dimeglumine,the parameters of renal IVIM were continuously and dynamically observed.The results showed that ADC value and D value of kidney were decreased in the first several time points after injection,and ADC value in medulla,D value recovery time longer than the cortex,and D * value and f value after injection did not change significantly in kidney. |
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