Objective To investigate the application value of time-spatial labeling inversion pulse (T-SLIP) in renal corticomedullary differentiaton and the best black blood inversion time (BBTI) value.Methods Totally 60 volunteers were included,who underwent abdominal MR scan with noncontrast-enhanced SSFP sequence combined with T-SLIP.All subjects were scanned with different BBTI (800,1 000,1 200,1 400,1 600,1 800 ms) using coronary T-SLIP SSFP sequence.The images quality was evaluated using a four-point scale method.The region of renal cortex and medulla was devised automatically based on the image training algorithm.The signal intensity ratio with the different BBTI was calculated through measuring the signal intensity of the renal cortex and medulla.And the best BBTI values were analyzed.Results When BBTI was 1 200 ms,the image score was the highest.The signal intensity ratio (SIR) had statistical difference among different BBTI groups (all P＜0.05),when BBTI was 1 200 ms,the SIR was the highest,and the contrast between the renal cortex and medulla was obvious.Conclusion T-SLIP technology can improve the visibility of renal corticomedullary without contrast agents.The optimal BBTI for the best corticomedullary differentiation is 1 200 ms.

Objective To prepare the coating of dexamethasone-eluting intravascular stent and observe the features of its delayed release in vitro.Methods Spray painting and dipping coating were used respectively to prepare stent coating,and then high performance liquid chromatography(HPLC)was used to detect the drug loading.The stents prepared by dipping coating were set in a flow of 50 ml PBS buffer at a velocity of 20 ml/min,and 0.5 ml buffer was collected at 6 h and 1,2,4,6,8,10,12,15 d respectively with another 0.5 ml fresh PBS being added immediately.The drug content of the 0.5 ml buffer was detected by HPLC for drug sustained release in vitro.Results The drug loading of stents prepared by spray painting was(24.26?5.23)?g,while that stents prepared by dipping coating for 4 d was(93.15?7.83)?g.Drugs were released slowly and the release rate reached 84% at 15 d.Conclusion The dipping coating-prepared stents have evident effect of sustained release.