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Objective To investigate the influence of low-tube current in combination with simultaneous iterative reconstruction algorithm on bone mineral density (BMD) of T12 and image quality with a chest phantom.Methods An adult male chest phantom was selected.CT scan of the chest was performed at tube voltage of 120 kV and five different tube currents (20,30,40,50,60 mAs) in combination with filtered back projection (FBP),iDose4 (Level 4) and iterative model reconstruction (IMR,Level 2),respectively.BMD of T12 in chest phantom and objective evaluation results on different tube currents and simultaneous iterative reconstruction techniques were compared.The subjective scoring of mediastinum and lung window imaging qualities at tube current of 20 mAs with IMR and tube current of 60 mAs with FBP were compared.The consistency between two observers was evaluated.Results There was no significant difference between BMD values nor CT values on different tube currents and simultaneous iterative reconstruction techniques of chest phantom (all P＞ 0.05),but the differences between SD values were statistically significant (P＜ 0.001).SD values obtained with IMR were lower than those of iDose4 and FBP at same tube currents (all P＜0.001).At tube current of 60 mAs with FBP,the consistency of two observers in mediastinum window was the best (Kappa=1,P＜0.001),while in lung window was medium (Kappa=0.64,P=0.002).At tube current of 20 mAs with IMR,the consistency of two observers in mediastinum window was medium (Kappa=0.64,P=0.002),while in lung window was the best (Kappa=1.00,P＜0.001).Conclusion Low-tube current in combination with simultaneous iterative reconstruction algorithm can reduce radiation dose without affecting the accuracy of BMD.
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Objective To investigate the reproducibility and accuracy of spinal BMD (bone mineral density) by low mA using adaptive statistic iterative reconstruction based on phantom model.Methods European spine phantom (ESP) was scanned with 5 different tube currents (40,60,80,100 and 120 mA) on the GE Revolution prototype.All data were transferred to the quantitative CT (QCT) PRO workstation for measuring the bone mineral density (BMD).And all data were reconstructed using different adaptive statistical iterative reconstruction veo (ASiR-V) weighting percentages from ASiR-V 0 filtered back projection(FBP) to ASiR-V 100％,at interval of 20％.Quantitative measurements of CT value,noise,and contrast noise ratio (CNR) of L1,L2 and L3 were measured in each group.The singlefactor analysis of variance (ANOVA) was used to compare the bone mineral density values of different mA and ASiR-V weighting percentages.Results Volume CT dose index(CTDIvol) and dose length product (DLP) were positively correlated with tube current(r =1).The BMD of ESP phantoms had no statistically significant differences among the multi-center lumbar spines L1,L2 and L3 at different doses under the same ASiR-V weighting percentages (P ＞ 0.05),as well as at the same dose under different ASiR-V weighting percentages(P ＞ 0.05).The error of bone density accuracy was within 6％.Conclusions Low dosage of 120 kV and 40 mA using ASiR-V without affecting the accuracy of BMD has the potential effect to reduce radiation dose without compromising image quality.
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Objective To explore the role of miR-20a on pulmonary surfactant synthesis of alveolar epithelial cells A549 and its potential mechanism.Methods Lentivirus miR-20a overexpression vector(miR-20a group) or lentivirus no-load vector(no-load group) was transfected into A549 cells,and the expression of green fluorescent protein(GFP) was observed to determinate the transfection effficiency;cell proliferation was detected by using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT);the bioinformatics software and database were applied to predict and analyze the target genes of miR-20a about lung development;expressions of miR-20a,pulmonary surfactant-associated protein A(SP-A),pulmonary surfactant-associated protein B(SP-B),pulmonary surfactant-associated protein C(SP-C) and pulmonary surfactant-associated protein D(SP-D) mRNA were detected by using quantitative real-time PCR(qPCR);the expressions of SP-A protein,SP-B protein,SP-C protein,SP-D protein and protein signal transducers and activators of transcription 3 (STAT3) were detected by using Western blot.Results Observation of GFP expression under a fluorescent microscope indicated similar transfection efficiency,and real time-PCR showed that the expression of miR-20a increased after being transfected with lentivirus miR-20a overexpression vector(3.85 ± 0.18)compared with the normal group (0.99 ± 0.04)and the no-load group (1.21 ± 0.12),and the differences were significant(t =10.85,9.64,all P ＜0.001).As a result,lentivirus miR-20a overexpression vector was constructed successfully.Online software predicted that STAT3 gene was likely to be the target gene of miR-20a.Compared with the normal group (24 h,48 h,72 h:0.23 ± 0.01,0.39 ± 0.01,0.56 ± 0.03) and the no-load group (24 h,48 h,72 h:0.25 ± 0.01,0.44 ± 0.05,0.59 ± 0.01),miR-20a did not change the cell proliferation at different time points(24 h,48 h,72 h:0.26 ± 0.01,0.41 ± 0.02,0.58 ± 0.02) (all P ＞ 0.05).Compared with the normal group (1.00 ± 0.05,1.24 ± 0.20,1.31 ± 0.09,0.89 ± 0.12) and the no-load group (0.76 ± 0.10,1.31 ± 0.13,1.50 ± 0.11,1.01 ± 0.11),miR-20a up-regulated the mRNA expressions of SP-A,SP-B,SP-C and SP-D (2.05 ± 0.17,2.14 ± 0.10,2.84 ± 0.09,1.66 ± 0.08),and the differences were significant (all P ＜ 0.05).Compared with the normal group (0.46 ± 0.01,0.27 ± 0.03,0.69 ± 0.01,0.43 ± 0.01) and no-load group (0.43 ± 0.01,0.21 ± 0.01,0.79 ± 0.02,0.44 ± 0.02),miR-20a also increased the protein expressions of SP-A,SP-B,SP-C and SP-D (0.55 ±0.01,0.47 ±0.05,0.96 ±0.02,0.59 ±0.03),the diffe-rences were statistically significant (all P ＜0.05).The expression of STAT3 in miR-20a group(0.37 ±0.05) was significantly lower than that in the normal group(0.60 ±0.04) and the no-load group (0.68 ±0.06),and the differences were statstically significant (all P ＜ 0.05) in A549.Conclusions STAT3 is a downstream target gene of miR-20a.miR-20a can promote pulmonary surfactant synthesis of alveolar epithelial cells A549 by inhibiting STAT3.
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Objective To study the roles of miR-20a in lipopolysaccharide induced inflammation of A549 cells and the possible mechanisms.Method The miR-20a mimic/inhibitor were transfected into A549 cells, and the cells were stimulated using lipopolysaccharide for 24 h.Interleukin-6 ( IL-6) and IL-8 were detected at mRNA level and protein level using real-time PCR and ELISA method , respectively.Protein expression of apoptosis signal regulating kinase 1 (ASK1)、P38、P-P38、JNK and P-JNK were detected using Western blot. Result Compared to mimic negative control group , the levels of mRNA and protein expression of IL-6 and IL-8 in the mimic group were all significantly decreased ( P<0.05).Compared to inhibitor negative control group , the levels of mRNA and protein expression of IL-6 and IL-8 in the inhibitor group were all significantly increased (P<0.05).The levels of ASK1, P-P38 and P-JNK protein in the mimic group were significantly lower than the mimic negative control group (P<0.05);the level of protein expression of ASK1, P-P38 and P-JNK in the inhibitor group were all higher than the inhibitor negative control group (P<0.05).Conclusion The regulation of ASK1 by miR-20a may play an important role in the inflammation process of acute respiratory distress syndrome .
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Objective To investigate the effectiveness of organ dose modulation (ODM) technology with respect to dose reduction and image quality of the sensitive organs during CTA of craniocervical arteries. Methods Ninety one patients suspected of arterial vascular disease and evaluated by CTA of craniocervical arterires were enrolled in this study. Patients were divided into group A (n=46) and group B (n=45) according to the order of examination. All patients hadCTA examination of craniocervical arteries. The ODM technique was used only in plain phase in group A and was used both in the plain phase and enhanced phase in group B. The tube current in the four direction (anterior,posterior,left,right) of thyroid and orbital area and radiation dose were recorded. The image quality of group A and group B was evaluated by objective indicators [CT attenuation values and contrast-to-noise ratio (CNR) of vessels in the thyroid area and orbital region ]and the subjective score. The independent samples t test was used for the statistical analysis of the objective indicators and nonparametric rank sum Mann-Whitney U test were used for subjective score. Results For A group, There were significant differences for the tube current at all directions of the thyroid gland and orbital area between the plain phase and the enhanced phase except the current at the posterior of the thyroid gland area(P value all0.05). Conclusion ODM technique can provide protective effect on the sensitive organs during craniocervical CTA examination without compromising the image quality.
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This paper presents the preliminary design of data acquisition system of a portable uroflowmeter. The system uses double-hole cantilever pressure sensor. The signal is transferred to ATmega644PA microprogrammed control unit (MCU), converted by A/D (analog to digital) convertor. Then the further data are processed and get the corresponding relationship of weight-time and two curves of urine flow and urinary flow rate. In the measurement accuracy of the device about urine flow, two factors about the placement and height of the data acquisition are analyzed to show the accuracy of the equipment through the Origin 8.0 data analysis software. The design is characterized by low cost and high speed of data collection, real-time, high accuracy.