| Objective: To discuss the physicochemical,magnetic characteristics of manganese hexacyanoferrate potassium potassium nanoparticles and its feasibility as MRI contrast agent by investigating its superficial syndrome, stability and magnetic characteristics.Methods: The size, shape and superficial syndrome of prepared manganese hexacyanoferrate potassium potassium nanoparticles was observed under transmission electron microscope. The mesoporous and phase structure of particles were detected by X ray powder diffraction, the longitudinal relaxation rate of the material was detected by 0.55 T nuclear magnetic resonance analyzer.Different concentrations(0.96、1.92、3.83、7.67 mmol/L)of manganese hexacyanoferrate potassium potassium nanosolution were detected by MR imagine in vitro.Analyze the correlation between the concentrations and the T1 signal intensity.Results: The prepared manganese hexacyanoferrate potassium potassium nanoparticles under the transmission electron microscope displayed as cube shape, having an average uniformed particle size, which were dispersed uniformly. The molecular formula of manganese hexacyanoferrate potassium potassium nanoparticles is KMn[Fe(CN)6]2H2O, which was determined by X ray powder diffraction and transmission electron energy spectrum diagram analysis. The particles had a longitudinal relaxation r1 of 2.0184 m M-1s-1.The difference of T1 signal intensity with different concentrations was very obvious, the signal intensity of images increased gradually as the concentration increased.Conclusions: The manganese hexacyanoferrate potassium potassium nanoparticles had such specificity as better stability, biocompatibility, and higher relaxation rate, the correlation between the concentration and T1 signal intensity was very obvious, can be used as effective T1 contrast agent of magnetic resonance imaging.Objective: To investigate the best injection concentration for enhancement effect by performing magnetic resonance enhanced scan for different organs of the rat(brain, heart, liver and kidney) using different injection concentrations of manganese hexacyanoferrate potassium nanoparticles, then analyzing the relationships between injection concentration and the degree of enhancement in different organs of the rat.Methods: 72 healthy male SD rats were randomly divided into 6 groups, each group with 12 rats for injecting different concentrations of contrast agent. Each group was then randomly divided into 2 teams, each team with 6 rats for scanning different organs(one team with brain scan, the other one with heat, liver and kidney scan). Different concentrations of manganese hexacyanoferrate potassium nanoparticles contrast agent were injected via the vein of tail. The concentrations were 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L and 60mmol/L respectively, the injection dose was 0.7ml/300 g. Different organs of the rat were scanned with TSE-T1 WI sequence before and after injection respectively. The SI, SNR and SER of different organs were analyzed and compared between different concentrations after enhancement using one-way analysis of variance. LSD method was used in pair wise comparison. The SI, SNR and SER of ventricle and pituitary, renal cortex and medulla which were injected with the same concentration were compared by the paired-samples t test.Results: SI of cerebral cortex after enhancement with different concentrations for 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L and 60mmol/L were507.50±130.29, 488.00±97.39, 549.50±72.19, 559.67±103.10, 525.33±64.46, 563.50±99.78 respectively, SNR were 20.21±2.31, 19.37±1.57, 23.61±3.39, 22.92±3.66, 24.02±5.25, 22.50±6.20 respectively. SER were 0.24±0.15, 0.20±0.17, 0.45±0.15, 0.42±0.28, 0.49±0.36, 0.40±0.37 respectively. The enhancement effect of different concentration contrast agent on cerebral cortex was non-significant.Pair wise comparison of SI, SNR and SER were all non-significant(P>0.05). SI of ventricle after enhancement with different concentrations were 834.83±113.48, 883.83±94.93, 922.50±108.91, 923.50±101.41, 1024.83±127.94, 890.67±124.63 respectively, SNR were 20.42±6.55, 23.20±2.05, 29.77±4.74, 33.44±5.50, 34.73±7.06, 22.96±2.93 respectively. SER were 0.27±0.43, 0.45±0.29, 0.87±0.55, 1.09±0.52, 1.18±0.69, 0.43±0.28 respectively. SI of pituitary after enhancement with different concentrations were 836.83±77.02, 846.00±84.24, 878.33±97.81, 928.17±87.61, 1023.67±95.11, 859.00±76.53 respectively, SNR were 28.35±7.03, 28.68±7.18, 29.93±8.22, 31.61±8.27, 34.97±9.35, 32.07±6.85 respectively. SER were 0.52±0.30, 0.54±0.31, 0.60±0.36, 0.69±0.36, 0.87±0.40, 0.72±0.31 respectively. The enhancement effect of the concentration of 45mmol/L on ventricle and pituitary was the most significant.SNR and SER of ventricle and pituitary were orderly increased with concentration of 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L, and they reached the highest at the concentration of 45mmol/L, while they decreased at concentration of 60mmol/L. Comparison of the SI of ventricle with different concentration: there were significant differences between the concentration of 45mmol/L and 7.5mmol/L, 15mmol/L and 20mmol/L(P<0.05). Comparison of the SNR of ventricle with different concentration: there were significant differences between the concentration of 7.5mmol/L, 15mmol/L, 60mmol/L and 20mmol/L, 30mmol/L, 45mmol/L, in pair wise comparison(P<0.05).Comparison of the SER of ventricle with different concentration: there were significant differences while compared the concentration of 7.5mmol/L with 20mmol/L, 30mmol/L, 45mmol/L respectively(P<0.05), there were significant differences while compared 15mmol/L, 60mmol/L with 30mmol/L, 45mmol/L in pair(P<0.05). Comparison of the SI of pituitary with different concentration: there were significant differences while compared the concentration of 45mmol/L with 7.5mmol/L, 15mmol/L,20mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SNR and SER of pituitary with different concentration: there were no significant differences(P>0.05). Comparison of the SI, SNR and SER of ventricle and pituitary with the same concentration: there were no significant differences except the concentration of 60mmol/L(P<0.05). SI of heart after enhancement with different concentrations for 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L and 60mmol/L were 488.50±177.76, 793.17±223.19, 888.50±146.51, 908.33±78.79, 949.33±76.76, 837.67±87.33 respectively, SNR were 26.86±3.45, 29.26±3.49, 29.54±3.29, 30.18±4.90, 32.11±5.00, 27.41±4.88 respectively, SER were 0.49±0.39, 0.61±0.37, 0.64±0.41, 0.67±0.42, 0.76±0.36, 0.56±0.56 respectively. SI, SNR and SER of heart were orderly increased with concentration of 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L, and they reached the highest at the concentration of 45mmol/L, while SNR and SER decreased at concentration of 60mmol/L. Comparison of the SI of heart with different concentration: there were significant differences while compared the concentration of 7.5mmol/L with 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SNR of heart with different concentration: there were significant differences between the concentration of 7.5mmol/L and 45mmol/L(P<0.05), there were no significant differences among other concentrations while compared them in pair(P>0.05). Comparison of the SER of heart with different concentration: there were no significant differences among each concentration(P>0.05). SI of liver after enhancement with different concentrations for 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L and 60mmol/L were 2588.67±389.30, 2868.83±180.85,2828.83±206.11, 2822.17±413.87, 3212.50±284.09, 2818.33±273.82 respectively, SNR were 33.63±7.32, 36.77±9.72, 37.51±4.32, 37.57±8.22, 46.13±6.72, 35.14±4.70 respectively, SER were 0.40±0.43, 0.52±0.48, 0.56±0.31, 0.60±0.56, 0.98±0.67, 0.51±0.50 respectively. SI, SNR and SER of liver were orderly increased with concentration of 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L, and they reached the highest at the concentration of 45mmol/L, while SNR and SER decreased at concentration of 60mmol/L. Comparison of the SI of liver with different concentration: there were significant differences while compared the concentration of 45mmol/L with 7.5mmol/L, 20mmol/L, 30mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SNR of liver with different concentration: there were significant differences while compared the concentration of 45mmol/L with 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SER of liver with different concentration: there were no significant differences among each concentration(P>0.05). SI of renal cortex after enhancement with different concentrations for 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L and 60mmol/L were 789.50±122.86, 887.17±95.04, 951.00±205.63, 1020.50±197.42, 1044.33±203.51, 986.33±123.07 respectively, SNR were 25.03±5.81, 28.15±5.66, 29.83±6.96, 30.39±5.35, 32.84±8.11, 26.04±3.45 respectively, SER were 0.32±0.38, 0.49±0.41, 0.56±0.33, 0.60±0.38, 0.70±0.31, 0.37±0.23 respectively. SI of renal medulla after enhancement with different concentrations for 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L and 60mmol/L were 732.67±137.17, 847.00±134.32, 872.17±184.87, 889.67±95.67, 943.83±138.50, 926.33±97.51 respectively, SNR were 18.34±2.65, 20.40±3.04, 22.35±1.50, 26.95±6.03, 29.76±6.72, 24.57±3.79 respectively, SER were 0.03±0.20, 0.14±0.13, 0.26±0.12, 0.53±0.43, 0.66±0.30, 0.38±0.26. SI, SNR and SER of renal cortex and medulla were both orderly increased with concentration of 7.5mmol/L, 15mmol/L, 20mmol/L, 30mmol/L, 45mmol/L, and they reached the highest at the concentration of 45mmol/L, while decreased at concentration of 60mmol/L. Comparison of the SI of renal cortex with different concentration: there were significant differences while compared the concentration of 7.5mmol/L with 30mmol/L, 45mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SNR of renal cortex with different concentration: there were significant differences between the concentration of 7.5mmol/L and 45mmol/L(P<0.05). Comparison of the SER of renal cortex with different concentration: there were no significant differences among each concentration(P>0.05). Comparison of the SI of renal medulla with different concentration: there were significant differences while compared the concentration of 7.5mmol/L with 45mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SNR of renal medulla with different concentration: there were significant differences while compared the concentration of 7.5mmol/L with 30mmol/L, 45mmol/L, 60mmol/L, 15mmol/L with 30mmol/L, 45mmol/L, 45mmol/L with 20mmol/L, 60mmol/L respectively(P<0.05). Comparison of the SER of renal medulla with different concentration: there were significant differences while compared the concentration of 7.5mmol/L with 30mmol/L, 45mmol/L, 60mmol/L respectively, 15mmol/L with 30mmol/L, 45mmol/L respectively, 20mmol/L with 45mmol/L(P<0.05). Comparison of the SI of renal cortex and medulla with the same concentration: there were significant differences in the concentration of 7.5mmol/L, 20mmol/L, 45mmol/L, 60mmol/L(P<0.05). Comparison of the SNR of renal cortex and medulla with the same concentration: there were significant differences in the concentration of 15mmol/L, 30mmol/L, 45mmol/L, 60mmol/L(P<0.05). Comparison of the SER of renal cortex and medulla with the same concentration: there were no significant differences in each concentration(P>0.05).Conclusions: SI, SNR and SER of different organs of rat(except cerebral cortex) reached the highest at concentration of 45 mmol/L, which was the best injection concentration for enhancement effect in different organs.Objective: To discuss the organ distribution and timeliness specificity of manganese hexacyanoferrate potassium nanoparticles using the best concentration(45mmol/L) as contrast agent, and analyze the enhancement effect and specificity of different organs after injecting the agent at different time points.Methods: 12 healthy male SD rats of the same age were randomly divided into 2 groups, each group with 6 rats for scanning different organs(one group with brain scan, the other one with heat, liver and kidney scan) with T1 WI sequence, then manganese hexacyanoferrate potassium nanoparticles contrast agent was injected via the vein of tail with the concentration of 45mmol/L, the injection dose was 1ml/300 g. The four organs of rat were scanned with TSE-T1 WI sequence at 5 min, 30 min, 1 h, 2 h, 3h, 4 h, 6 h and 24 h after injection. The enhancement effect of the four organs were observed, the signal intensity of the four organs and standard deviation of background noise signal intensity were measured before and after enhancement scan. Signal to noise ratio and enhancement rate of the four organs were calculated repectively. Signal-noise ratio(SNR) and signal enhancement ratio(SER)-time dynamic curve were drawn. SI, SNR and SER of the four organs were compared after enhancement at each time point respectively by using one-way analysis of variance.The SI, SNR and SER of ventricle and pituitary, renal cortex and medulla which were injected at the same time point were compared by the paired-samples t test.Results: SI of cerebral cortex before injection and 5min, 30 min, 1h, 2h, 3h, 4h, 6h and 24 h after injection were 682.67±256.57, 561.17±84.49, 563.00±158.00, 651.00±107.52, 599.67±162.33, 662.33±144.10, 639.33±141.24, 635.33±125.22, 719.33±116.87 respectively, SNR were 23.67±13.27, 20.52±6.99, 25.89±16.34, 15.60±6.14, 24.53±8.75, 13.76±4.23, 19.56±7.33, 19.01±5.16, 18.44±3.90 respectively, SER at 5min~24h after injection were 0.04±0.47, 0.21±0.52,-0.19±0.43, 0.27±0.72,-0.16±0.65, 0.17±0.83, 0.08±0.68,-0.03±0.51 respectively. SI of ventricle before injection and 5min, 30 min, 1 h, 2 h, 3h, 4 h, 6h and 24 h after injection were 464.67±98.25, 716.00±161.17, 1001.83±343.13, 955.50±301.75, 836.50±198.25, 829.83±284.69, 816.17±344.74, 781.50±106.24, 489.50±108.25 respectively, SNR were 17.46±8.96, 26.06±4.20, 38.64±2.01, 29.06±9.06, 27.58±7.53, 25.65±8.17, 26.03±14.86, 23.86±4.52, 15.61±6.60 respectively, SER at 5min~24h after injection were 1.21±1.76, 2.73±4.66, 1.51±2.26, 1.30±2.04, 1.29±1.41, 1.04±1.52, 1.00±1.69, 0.24±1.17 respectively. SI of pituitary before injection and 5min, 30 min, 1h, 2h, 3h, 4h, 6h and 24 h after injection were 435.50±92.36, 682.83±124.47, 880.50±188.18, 936.67±283.23, 772.00±139.29, 755.00±231.49, 759.50±295.85, 697.33±133.56, 475.50±112.48 respectively, SNR were 15.33±8.50, 24.17±3.66, 25.50±7.12, 35.83±19.61, 27.83±9.20, 24.16±14.59, 23.67±7.61, 22.01±4.33, 14.17±6.34 respectively, SER at 5min~24h after injection were 0.93±1.29, 1.04±1.82, 2.49±4.16, 1.28±2.12, 1.17±1.46, 0.87±1.61, 0.83±1.54, 0.16±1.09 respectively. The SI, SNR and SER of cerebral cortex at different time point were non-significant(P>0.05). The enhancement of ventricle increased rapidly after injecting contrast agent, and reached the peak at 30 min, so did the SNR and SER, then the enhancement decreased with the time, kept stable at 2 ~ 4h, and returned to the level unenhanced after 24 h. Comparing SI of ventricle at the time point of 30min~6h after injection with unenhanced, SNR of ventricle at the time point of 30 min after injection with unenhanced, the differences were statistically significant(P<0.05). There were no significant differences of SER of ventricle at each time point after enhancement(P>0.05). Pituitary manifested marked enhancement after injecting the contrast agent, and reached the peak at 1h, so did the SNR and SER, then decreased gradually with the time, and returned to the level unenhanced after 24 h. Comparing SI of pituitary at the time point of 30min~6h after injection with unenhanced, SNR of pituitary at the time point of 1h~2h after injection with unenhanced, the differences were statistically significant(P<0.05). There were no significant differences of SER of pituitary at each time point after enhancement(P>0.05). Comparison of the SNR of ventricle and pituitary at different time point: there were significant differences at the time point of unenhanced, 5min, 6h, and 24h(P<0.05). SI of heart before injection and 5min, 30 min, 1h, 2h, 3h, 4h, 6h and 24 h after injection were 673.67±200.13, 1756.83±1038.10, 2109.83±1373.18, 2146.00±858.32, 2119.83±1183.29,1806.17±563.98,1505.67±378.32, 1781.50±786.99, 534.50±296.95 respectively, SNR were 9.63±2.24, 26.24±4.60, 28.89±9.41, 30.93±7.42, 27.15±1.31, 26.04±4.99, 23.65±9.63, 18.94±4.94, 9.47±1.80 respectively, SER at 5min~24h after injection were 1.90±0.97, 1.95±0.47, 2.37±1.10, 2.03±1.67, 1.85±0.93, 1.63±1.36, 1.15±1.03, 0.05±0.36 respectively. Heart manifested marked enhancement after injecting the contrast agent, the SI, SNR and SER reached the peak at 1h, kept stable at 30min~3h, then decreased gradually, and returned to the level unenhanced after 24 h. Comparing SI and SNR of heart at the time point of 5min~6h after injection with unenhanced, SER of heart at the time point of 5min~4h after injection with 24 h, the differences were statistically significant(P<0.05). SI of liver before injection and 5min, 30 min, 1h, 2h, 3h, 4h, 6h and 24 h after injection were 1055.00±430.20,2224.00±561.50,3040.17±450.79,2389.50±344.76, 2012.00±172.13,1715.33±318.68,1316.33±154.64,1117.17±244.66,991.50±305.45 respectively, SNR were 18.62±8.30,37.26±1.56,44.04±8.13,40.71±1.03,38.31±1.16,35.39±7.49,31.20±4.72,23.57±5.59,17.69±7.77 respectively, SER at 5min~24h after injection were 1.28±1.03,1.61±0.86,1.41±0.87,1.39±1.20,1.10±0.73,0.91±0.73,0.40±0.53,0.07±0.53 respectively. The enhancement of liver increased rapidly after injecting contrast agent, the SI, SNR and SER reached the peak at 30 min, then the enhancement began to decreased with the time but still kept marked enhancement, and decreased obviously after 2h, returned to the level unenhanced after 24 h. Comparing SI of liver at the time point of 5min~3h after injection with unenhanced, SNR of liver at the time point of 5min~4h after injection with unenhanced, SER of liver at the time point of 5min~3h after injection with 24 h, SER of liver at the time point of 30min~2h after injection with 6h, the differences were statistically significant(P<0.05). SI of renal cortex before injection and 5min, 30 min, 1h, 2h, 3h, 4h, 6h and 24 h after injection were 263.50±39.36, 692.17±201.25, 734.83±127.39, 788.00±238.75, 981.33±145.34, 801.00±129.50, 755.83±99.15, 617.67±171.03, 423.50±211.94 respectively, SNR were 4.77±0.82, 15.71±4.62, 16.81±7.22, 17.30±3.86, 23.47±5.60, 20.66±7.79, 17.59±6.18, 13.43±6.81, 10.00±5.30 respectively, SER at 5min~24h after injection were 2.46±0.94, 3.09±1.36, 3.26±2.18, 5.23±1.55, 3.12±0.87, 2.21±0.58, 1.62±0.96, 0.89±0.95 respectively. SI of renal medulla before injection and 5min, 30 min, 1h, 2h, 3h, 4h, 6h and 24 h after injection were 232.00±43.47, 642.67±183.28, 692.50±127.27, 729.83±209.58, 753.50±105.57, 781.17±152.59, 917.17±154.58, 710.00±236.08, 471.83±197.85 respectively, SNR were 4.59±0.82, 15.28±4.64, 15.89±7.30, 16.02±4.36, 18.86±6.66, 20.02±8.16, 24.28±11.93, 14.53±7.74, 10.62±6.19 respectively, SER at 5min~24h after injection were 2.34±0.94, 2.61±1.21, 2.69±2.11, 3.13±1.44, 3.39±1.80, 4.47±3.17, 2.04±1.07, 1.37±1.54 respectively. The enhancement of renal cortex and medulla were gradually increased after injecting contrast agent, the SI, SNR and SER of renal cortex reached the peak at 2h, and the renal medulla reacher the peak at 4h, the enhancement of renal cortex was higher than medulla before 4h, then lower than medulla after 4h, and the medulla manifested as a circular structure with marked enhancement, the enhancement of the renal cortex and medulla were still higher than the level unenhanced after 24 h. Comparing SI and SNR of renal cortex at the time point of 5min~6h after injection with unenhanced, SNR of renal medulla at the time point of 5min~6h after injection with unenhanced, the differences were statistically significant(P<0.05). Comparing SER of renal cortex at the time point of 2h after injection with 5min, 30 min, 1h, 3h, 4h, 6h, 24 h respectively, 24 h after injection with 5min, 30 min, 1h, 3h respectively, 6h after injection with 1h, 3h respectively, the differences were statistically significant(P<0.05). Comparing SER of renal medulla at the time point of 4h after injection with 5min, 6h, 24 h respectively, the differences were statistically significant(P<0.05). Comparison of the SI, SNR and SER of renal cortex and medulla at different time point: the SI at the time point of unenhanced~2h and 4h~24h, the SNR at the time point of unenhanced~2h, the SER at the time point of unenhanced~2h and 6h, the differences were statistically significant(P<0.05).Conclusions: The enhancement effect of manganese hexacyanoferrate potassium nanoparticle contrast agents on different organs,among them the liver was enhanced the most significant, the enhancement reached the peak at about 30 min, and the enhancement lasted for a long time, having a longer imaging window; The enhancement of heart took the second place, the kidney enhanced slowly, the enhancement of renal cortex reached the peak at 2h, the renal medulla reached the peak at 4h; The enhancement of cerebral cortex was not obvious. There was a certain specificity when the manganese hexacyanoferrate potassium nanoparticle contrast agents used on liver enhancement. |
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