1.Effects from Side Branch Diameter of Intracranial Aneurysm on Hemodynamic Parameters after Flow Diverter Implantation
Hui GAO ; Yunzhang CHENG ; Xiangkun LIU ; Bin BAI ; Linjing PENG
Journal of Medical Biomechanics 2020;35(4):E403-E409
Objective To comprehensively consider the effect of low diverter (FD) implantation on aneurysmal sac and its branches, so as to provide references for making a more reasonable surgical strategy for intracranial aneurysm embolization in clinical practice. Methods Based on computational fluid dynamics (CFD) method, the FD implantation procedure was simulated by using porous media model innovatively. Changes in hemodynamic parameters of aneurysmal sac and side branch with different diameters before and after FD implantation were compared and analyzed, such as blood flow field, velocity, wall pressure and wall shear stress (WSS). Results FD changed the hemodynamic characteristics of aneurysms. The blood flow velocity decreased significantly. The WSS on aneurysmal neck increased, while the difference of WSS between proximal and distal cervical area reduced conversely. Different side branch diameters of vessels had different effects on hemodynamic characteristic changes. The larger diameter would cause the greater blood flow reduction in side branch after FD implantation, but the decrease in velocity of aneurysmal sac and pressure on aneurysmal roof became smaller simultaneously. Meanwhile, the increase of WSS on aneurysmal neck was inversely proportional to the diameter of side branch. Conclusions The larger branch diameter of vessels would cause the worse effect of FD embolization therapy for intracranial aneurysm, worse atherosclerosis improvements and greater possibilities of branch occlusion or other ischemic complications. Doctors should pay more attention to such cases in FD interventional intravascular embolization in clinic.
2.Sensitivity Analysis of Flow Diverter Treatment of Intracranial Aneurysm Using Porous Media Model
Bin BAI ; Yunzhang CHENG ; Hui GAO ; Nan LÜ ; Linjing PENG
Journal of Medical Biomechanics 2020;35(6):E718-E724
Objective To simulate the hemodynamic effects of different flow diverters (FD) parameters by using computational fluid dynamics (CFD) technology, so as to develop a more reasonable FD embolization strategy before operation. Methods The porous media model was used to simulate the process of FD implantation into aneurysms, and the initial values of its own unique porous media momentum source parameters (permeability and inertial resistance) were calculated for a specific FD (Tubridge).The changes of hemodynamic parameters such as blood flow velocity, wall shear stress (WSS), volume flow and pressure of aneurysm-roof were compared under different situations (initial values of 80%, 90%, 100%, 110% and 120%), and the sensitivity analysis on hemodynamic parameters of patient-specific intracranial aneurysms (IA) for the porous media model was further conducted. Results The sensitivity of IA hemodynamic parameters to the permeability of porous media model was as follows: WSSparent-artery>WSSaneurysm>paneurysmal-roof, but the sensitivity to inertia resistance was relatively lower. Conclusions By using the porous media model, different metal coverages (MC) of FD could be simulated by choosing different permeability parameters, so it is necessary to adjust specific permeability settings during modeling of FD with different MC.
3.Study on Optimization of Formulation and Technology of Citronellol Submicroemulsion
Jiajia YANG ; Wanrong LI ; Jianqing PENG ; Ting XIAO ; Linjing WU ; Xue ZHOU ; Zengqiu YANG ; Feng JIANG ; Yang DING ; Xiangchun SHEN ; Ling TAO
China Pharmacy 2020;31(14):1704-1710
OBJECTIVE:To optimize the p reparation technology of citronellol submicroemulsion. METHODS :The content of citronellol in Citronellol submicroemulsion was determined by HPLC. Citronellol submicroemulsion by high-speed shearing dispersion-high pressure homogenization method ,with centrifugation stability constant (ke) and particle size were used as evaluation indexes. Its formulation and preparation technology were optimized and validated. Drug-loading amount and encapsulation rate of the preparation were detected. RESULTS :The linear range of citronellol were 4-64 μg/mL(R 2=0.999 9). RSDs of precision ,stability(24 h)and reproducibility tests were all lower than 3%. The recoveries were 97.64%-101.97%(RSD= 2.28%,n=3),97.71%-99.50%(RSD=1.29%,n=3),96.87%-101.48%(RSD=2.86%,n=3). The optimal formulation included that total weight of soybean oil and medium chain triglycerides (1 ∶ 1,g/g)was 3.75 g,1.2% soybean phospholipid was 0.6 g, cholesterol was 0.06 g,citronellol was 1.25 g,0.6 % sodium oleate was 0.3 g,15-hydroxystearic acid polyethylene glycol ester was 0.75 g,poloxamer 188 was 0.75 g,water added to 50 mL. After prepared by optimal technology at 4 ℃ which contained shearing speed of 13 000 r/min,lasting for 5 min, primary emulsion was adjusted to pH 7 with dilute hydro- chloric acid ,and homogenized with 600 Bar high pressure for 1434412440@qq.com 5 min. The parameters of Citronellol submicroemulsion accor- ding to optimal formulation and technology contained mean particle size of (91.05±0.26)nm,PDI of (0.20±0.01), Zeta-potential of (-30.86±0.39)mV,average content of 649511230@qq.com citronellol(100.21±0.01)%,the drug-loading amount was (2.481 7 ± 0.000 7) mg/mL,the encapsulation rate was (99.27 ± 0.03)% . CONCLUSIONS :The optimal formulation and technology is stable and feasible.