Objective To reconstruct sparse views CT image based on defective projection data.Methods The position of bad bins in detector determined whether the linear interpolation was applied to the defective projection data.Moreover,reconstruction of air pixels in CT image was achieved rapidly and accurately.Results he experimental results showed that the proposed method could solve the problem from classical ART-TV method that the robustness was unstable due to the different positions of bad bin in CT detector.Conclusion Compared to analytical reconstruction methods,iterative methods can solve the reconstruction problems in this modality so that the radiologist is facilitated to perform image processing and quantitative analysis.

Objective To evaluate the effects on catheter related blood stream infection by different dressing frequency of peripherally inserted central catheter(PICC)with neonates. Methods A systematic review of randomized controlled trials (RCTs) from databases, Data were searched about the transparent dressing replacement frequency for neonatal PICC catheterization. The meta-analysis was performed by using RevMan 5.2 software. Results Nine RCTs were included in a total of 1 730 patients. Meta analysis showed that there was no significant difference in the incidence of PICC puncture dressing, catheter-related infections (including puncture port infection, catheter-related blood flow infection, catheter bacterial colonization) at every 3, 5, and 7 days (P> 0.05). Conclusion the dressing of PICC catheter are replaced will not increase the incidence of catheter-related infections within 7 days, throughout the more appropriate frequency of dressing replacement is once every 7 days.

Objective:To study the safety of different peripherally inserted central catheter (PICC) dressing replacement frequencies in preterm infants.Method:From June 2017 to February 2020, preterm infants were enrolled in this prospective randomized controlled study. Preterm infants with PICC were randomly assigned into 7 d, 11 d and 14 d dressing replacement groups using online randomization software. Polyurethane transparent dressing and the same dressing replacement method were used in all three groups. The incidences of catheter-related bloodstream infection (CRBSI) and positive skin bacterial culture at dressing site were compared among the three groups.Result:A total of 296 cases were enrolled, including 96 cases in the 7 d group, 108 cases in the 11 d group and 92 cases in the 14 d group. The incidences of CRBSI in three groups were 2.5/1 000 catheter day in 7 d group, 1.1/1 000 catheter day in 11 d group and 0.8/1 000 catheter day in 14 d group. The incidences of catheter pathogen colonization were 1.0% in 7 d group, 0.9% in 11 d group and 0% in 14 d group. The positive rates of skin bacterial culture at dressing site were 1.0% in 7 d group, 2.8% in 11d group and 2.2% in 14 d group. The incidences of PICC exit site infection in three groups were 1.0% in 7 d group, 0.9% in 11d group and 1.1% in 14 d group and no significant differences existed among the groups ( P>0.05). Gram-positive cocci were the main bacteria [91.7% (11/12)] of CRBSI and skin bacterial culture at dressing site and gram negative bacilli accounted for 8.3% (1/12). No fungal infection were found. Conclusion:It is safe to replace the PICC dressing in premature infants as needed within 14 days if the dressing is intact without curling, bleeding and exudation.