| ObjectiveMaking the animal model of early stage diabetic nephropathy indcuced by STZ in rat and to scan the two kidney by diffusion-weighted imaging and measurement ADC of the kidney layers displayed in DWI were obtained and compared to those measured in pathology and in the detection of microdose albumin in urine. To clear the diagnostic value by measurement ADC in early diabetic nephropathy and lay the imageological basis for clinical diagnosis of the disease.Material and methodsMaking the animal model of early stage diabetic nephropathy in 40 rats. Ten of them to be a control group, given the same doze of citric acid. The others to be a model group, which intraperitoneal injection by STZ, can divide into diabetes four weeks group (G1), eight weeks group (G2), twelve weeks group (G3), and each group has 10 rats. Measuring the 40 rats'blood sugar and regularly weight once every two weeks after the animal model made. The FFE-echo planar imaging DWI and Common imaging sequence T1WI and T2WI of the kidney in rats were performed on a 1.5 Tesla magnetic resonance system according to the week Four, eight and twelve. Gradient factor is 0 s/mm2,130 s/mm2,260 s/mm2,390 s/mm2,300 s/mm2,500 s/mm2,800 s/mm2. Observe the change of kidney structure and signal intensity and measuring ADC in ADC map at different time slot. Using rat microalbuminuria(ALB) enzyme-linked immunosorbent analysis the determination of microalbuminuria. Meanwhile, comparison ADC whether there were differences between different groups by independent sample T-test and compared ADC with pathology and the detection of microdose albumin in urine by correlation analysis and Multiple regression analysis. ResultsThe difference between model group and control group of blood sugar and weight of different period are have statistically significant (blood sugar:P<0.05, weight:P<0.05). The ADC in cortex of 9 rats of control group were (1.25×103±101.27)μm2/s, the outer stripes of the outer medulla were (0.92×103±138.86)μm2/s, the Inner stripes of the outer medulla were (1.52×103±302.47)μm2/s, the inner medulla were (1.15×103±228.22)μm2/s, all of G1 and 5 rats of G2 is the same as control group. One rat of G2 and 7 rats of G3 clear displaying the renal parenchyma layer structure of the rats. The ADC in CO of the four layer were(1.32×103±161.55)μm2/s; OS were(1.44×103±304.39)μm2/s; IS were(1.84×103±208.82)μm2/s; IM were(1.14×103±421.61)μm2/s, the last one of G3 is the same as control group. The difference between G2 and control group ADC of renal parenchyma CO layer have a statistically significant (P<0.05). The difference between G3 and control group ADC value of renal parenchyma OS and IS layer have statistically significant (P<0.05). The model group renal parenchyma display obvious change of diabetic nephropathy in pathology, glomerular swelling, variant, mesangial cells hyperplasia and thickening of glomerular basement membrane, etc. The difference between model group and control group pathological results have a statistically significant(P<0.05). The difference between model group and control group Microalbuminuria have a statistically significant (P<0.05). The results of pathological and Microalbuminuria and the results of ADC (CO and OS) showed a positive linear correlation(R=0.467).ConclusionsThe results of pathological and Microalbuminuria and the results of ADC (CO and OS) showed a positive linear correlation(R=0.467). To distinct the renal parenchymal change by measured ADC in diabetic nephropathy and realize there has important value in diabetic nephropathy diagnosis. That could be used as a diabetic nephropathy conventional imaging methods. |
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