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Monitoring the progression of renal fibrosis by T2-weighted signal intensity and diffusion weighted magnetic resonance imaging in cisplatin induced rat models.

Wu HH, Jia HR, Zhang Y, Liu L, Xu DB, Sun HR - Chin. Med. J. (2015)

Bottom Line: OM revealed remarkable hyperintense and broadened before it became an obscure thread, while CO demonstrated moderate hyperintense and IM didn't show significant change on T2WI.On all three stripes, ADC values decreased firstly then kept increasing since the 4 th day; f values decreased on all stripes; D values had a tendency to increase with fluctuations but the changes didn't achieve statistical significance; DFNx01 values increased at the 2 nd day then tended to be steady thereafter.All of T2-weighted SI, ADC, and biexponential models parameters vary during fibrotic process; biexponential model is superior to monoexponential model in separating changes of microperfusion together with tubular flow from pure diffusion.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Tianjin Medical University Hospital, Tianjin, China.

ABSTRACT

Background: Diffusion weighted imaging (DWI), with the applying of intravoxel incoherent motion model, has showed promising results in obtaining additional information about microperfusion and tubular flow associated with morphologic changes in chronic kidney diseases. The study aims to evaluate the potential of T2-weighted signal intensity (SI) and DWI with mono- and bi-exponential models to reflect the serial changes on cisplatin (CP) induced rat renal fibrosis models.

Methods: Magnetic resonance exams were performed prior to and 2 nd day, 4 th day, 6 th day, 8 th day, 2 nd week, 3 rd week and 4 th week after CP injection at a 3.0T with an animal coil. Besides T2-weighted images (T2WI), DWI of 13 b values from 0 to 1500 s/mm 2 was acquired. Apparent diffusion coefficient (ADC), fluid fraction f, pure diffusivity D and pseudodiffusivity DFNx01 values were calculated. The regions of interest were placed on cortex (CO), outer stripe of the outer medulla (OM) and inner stripe of the outer medulla (OM), parameters were measured and compared among different time points. Five rats were scarified at each time point for pathological examination.

Results: OM revealed remarkable hyperintense and broadened before it became an obscure thread, while CO demonstrated moderate hyperintense and IM didn't show significant change on T2WI. On all three stripes, ADC values decreased firstly then kept increasing since the 4 th day; f values decreased on all stripes; D values had a tendency to increase with fluctuations but the changes didn't achieve statistical significance; DFNx01 values increased at the 2 nd day then tended to be steady thereafter. Pathological findings revealed tubules epitheliums swelling followed by inflammation cells infiltration, interstitial fibrosis was observed since the 2 nd week.

Conclusions: All of T2-weighted SI, ADC, and biexponential models parameters vary during fibrotic process; biexponential model is superior to monoexponential model in separating changes of microperfusion together with tubular flow from pure diffusion.

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Serial morphologic changes of rat bilateral kidneys prior to and after CP injection on coronal fat suppressed fast recovery fast spin echo T2-weighted images. (a) Healthy kidneys; (b-h) 2nd day, 4th day, 6th day, 8th day, 2nd week 3rd and 4th week after CP injection. On healthy kidneys prior to CP injection, CO and OM showed similar moderate signal intensity, and IM showed relative hyperintense. After CP injection, OM revealed a remarkable hyperintense stripe with distinct boundaries with CO and IM; it gradually broadened and became obscure and less hyperintense till the 4th week after CP injection. CO revealed slightly increased intensity at the 2nd days, then decreased to the normal level 2 days later and kept increasing thereafter. IM changed slightly during the process. CP: Cisplatin; OM: Outer stripe of outer medulla; IM: Inner stripe of outer medulla; CO: Renal cortex.
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Figure 1: Serial morphologic changes of rat bilateral kidneys prior to and after CP injection on coronal fat suppressed fast recovery fast spin echo T2-weighted images. (a) Healthy kidneys; (b-h) 2nd day, 4th day, 6th day, 8th day, 2nd week 3rd and 4th week after CP injection. On healthy kidneys prior to CP injection, CO and OM showed similar moderate signal intensity, and IM showed relative hyperintense. After CP injection, OM revealed a remarkable hyperintense stripe with distinct boundaries with CO and IM; it gradually broadened and became obscure and less hyperintense till the 4th week after CP injection. CO revealed slightly increased intensity at the 2nd days, then decreased to the normal level 2 days later and kept increasing thereafter. IM changed slightly during the process. CP: Cisplatin; OM: Outer stripe of outer medulla; IM: Inner stripe of outer medulla; CO: Renal cortex.

Mentions: Cortex (2.35 ± 0.40) and OM (2.35 ± 0.40) couldn’t be distinguished between each other, and IM showed relative hyperintense (3.13 ± 0.61) prior to CP injection. Two days after CP injection, OM began to appear as a hyperintense stripe (3.78 ± 0.72, P < 0.05) with distinct boundaries with CO and IM; then it gradually broadened and became less intense with transit downward fluctuation but beyond normal level during 4th day and 4th week (P < 0.05), consequently it shrink to be an obscure thread 4 weeks after CP injection. CO revealed slightly increased intensity (2.60 ± 0.41, P < 0.05) at the 2nd days after injection, then decreased to normal level (2.28 ± 0.51, P > 0.05) 2 days later then appeared as steady hyperintense thereafter (P < 0.05). IM showed the transit and moderate hypointense (2.52 ± 0.72, P < 0.05) at only 4th day [Figures 1 and 2].


Monitoring the progression of renal fibrosis by T2-weighted signal intensity and diffusion weighted magnetic resonance imaging in cisplatin induced rat models.

Wu HH, Jia HR, Zhang Y, Liu L, Xu DB, Sun HR - Chin. Med. J. (2015)

Serial morphologic changes of rat bilateral kidneys prior to and after CP injection on coronal fat suppressed fast recovery fast spin echo T2-weighted images. (a) Healthy kidneys; (b-h) 2nd day, 4th day, 6th day, 8th day, 2nd week 3rd and 4th week after CP injection. On healthy kidneys prior to CP injection, CO and OM showed similar moderate signal intensity, and IM showed relative hyperintense. After CP injection, OM revealed a remarkable hyperintense stripe with distinct boundaries with CO and IM; it gradually broadened and became obscure and less hyperintense till the 4th week after CP injection. CO revealed slightly increased intensity at the 2nd days, then decreased to the normal level 2 days later and kept increasing thereafter. IM changed slightly during the process. CP: Cisplatin; OM: Outer stripe of outer medulla; IM: Inner stripe of outer medulla; CO: Renal cortex.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4834773&req=5

Figure 1: Serial morphologic changes of rat bilateral kidneys prior to and after CP injection on coronal fat suppressed fast recovery fast spin echo T2-weighted images. (a) Healthy kidneys; (b-h) 2nd day, 4th day, 6th day, 8th day, 2nd week 3rd and 4th week after CP injection. On healthy kidneys prior to CP injection, CO and OM showed similar moderate signal intensity, and IM showed relative hyperintense. After CP injection, OM revealed a remarkable hyperintense stripe with distinct boundaries with CO and IM; it gradually broadened and became obscure and less hyperintense till the 4th week after CP injection. CO revealed slightly increased intensity at the 2nd days, then decreased to the normal level 2 days later and kept increasing thereafter. IM changed slightly during the process. CP: Cisplatin; OM: Outer stripe of outer medulla; IM: Inner stripe of outer medulla; CO: Renal cortex.
Mentions: Cortex (2.35 ± 0.40) and OM (2.35 ± 0.40) couldn’t be distinguished between each other, and IM showed relative hyperintense (3.13 ± 0.61) prior to CP injection. Two days after CP injection, OM began to appear as a hyperintense stripe (3.78 ± 0.72, P < 0.05) with distinct boundaries with CO and IM; then it gradually broadened and became less intense with transit downward fluctuation but beyond normal level during 4th day and 4th week (P < 0.05), consequently it shrink to be an obscure thread 4 weeks after CP injection. CO revealed slightly increased intensity (2.60 ± 0.41, P < 0.05) at the 2nd days after injection, then decreased to normal level (2.28 ± 0.51, P > 0.05) 2 days later then appeared as steady hyperintense thereafter (P < 0.05). IM showed the transit and moderate hypointense (2.52 ± 0.72, P < 0.05) at only 4th day [Figures 1 and 2].

Bottom Line: OM revealed remarkable hyperintense and broadened before it became an obscure thread, while CO demonstrated moderate hyperintense and IM didn't show significant change on T2WI.On all three stripes, ADC values decreased firstly then kept increasing since the 4 th day; f values decreased on all stripes; D values had a tendency to increase with fluctuations but the changes didn't achieve statistical significance; DFNx01 values increased at the 2 nd day then tended to be steady thereafter.All of T2-weighted SI, ADC, and biexponential models parameters vary during fibrotic process; biexponential model is superior to monoexponential model in separating changes of microperfusion together with tubular flow from pure diffusion.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Tianjin Medical University Hospital, Tianjin, China.

ABSTRACT

Background: Diffusion weighted imaging (DWI), with the applying of intravoxel incoherent motion model, has showed promising results in obtaining additional information about microperfusion and tubular flow associated with morphologic changes in chronic kidney diseases. The study aims to evaluate the potential of T2-weighted signal intensity (SI) and DWI with mono- and bi-exponential models to reflect the serial changes on cisplatin (CP) induced rat renal fibrosis models.

Methods: Magnetic resonance exams were performed prior to and 2 nd day, 4 th day, 6 th day, 8 th day, 2 nd week, 3 rd week and 4 th week after CP injection at a 3.0T with an animal coil. Besides T2-weighted images (T2WI), DWI of 13 b values from 0 to 1500 s/mm 2 was acquired. Apparent diffusion coefficient (ADC), fluid fraction f, pure diffusivity D and pseudodiffusivity DFNx01 values were calculated. The regions of interest were placed on cortex (CO), outer stripe of the outer medulla (OM) and inner stripe of the outer medulla (OM), parameters were measured and compared among different time points. Five rats were scarified at each time point for pathological examination.

Results: OM revealed remarkable hyperintense and broadened before it became an obscure thread, while CO demonstrated moderate hyperintense and IM didn't show significant change on T2WI. On all three stripes, ADC values decreased firstly then kept increasing since the 4 th day; f values decreased on all stripes; D values had a tendency to increase with fluctuations but the changes didn't achieve statistical significance; DFNx01 values increased at the 2 nd day then tended to be steady thereafter. Pathological findings revealed tubules epitheliums swelling followed by inflammation cells infiltration, interstitial fibrosis was observed since the 2 nd week.

Conclusions: All of T2-weighted SI, ADC, and biexponential models parameters vary during fibrotic process; biexponential model is superior to monoexponential model in separating changes of microperfusion together with tubular flow from pure diffusion.

Show MeSH
Related in: MedlinePlus