The optimal velocity encoding of phase-contrast magnetic resonance angiography （PC MRA） in measuring cerebral blood flow volume （BFV） ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional （2D） PC ...The optimal velocity encoding of phase-contrast magnetic resonance angiography （PC MRA） in measuring cerebral blood flow volume （BFV） ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional （2D） PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encoding was set to 80 cm/s. Results of the measurements showed that the error rate was 7.0±6.0% in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateral common carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery ＋ external carotid artery and ipsilateral common carotid artery. In addition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore, after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accurate in the determination of BFV in the carotid arteries.展开更多
Objective:To systematic evaluation by the dorsalis pedis artery puncture for bed patients blood gas analysis of application effect of impact.Methods:A randomized controlled trial of the effect of arterial blood extrac...Objective:To systematic evaluation by the dorsalis pedis artery puncture for bed patients blood gas analysis of application effect of impact.Methods:A randomized controlled trial of the effect of arterial blood extraction on blood gas analysis in PubMed,CNKI,Wanfang database and VIP database.After selecting the literature,extracting the data and evaluating the quality of the literature.Meta- analysis was carried out by RevMan 5.3 software.Results:Twelve randomized controlled trials were included and 1696 patients were enrolled.After meta-analysis,the arterial puncture can effectively improve the success of arterial puncture in patients with bed [Z = 5.78,95%CI(1.90,3.66),P<0.001],reduce the occurrence of hematoma [Z = 4.27,95%CI(0.19,0.54),P<0.001],reduce the mistaken into the vein [Z = 4.60,95%CI(0.08,0.36),P<0.001],reduce cyanosis [Z = 2.84,95%CI(0.23,0.81),P<0.008],the difference was statistically significant.Conclusion:Dorsalis pedis artery puncture can improve the success rate of blood gas analysis in bedridden patients,reduce the incidence of hematoma and the incidence of venous leakage,and can be widely used in clinical practice.展开更多
This paper presents the development of the blood flow simulation in two dimensions over the real geometry of the femoral artery. The Navier-Stokes equations are solved using the finite element method, to obtain the di...This paper presents the development of the blood flow simulation in two dimensions over the real geometry of the femoral artery. The Navier-Stokes equations are solved using the finite element method, to obtain the distributions of the blood pressure and flow velocity in multiple instants of time and different places of the femoral artery and thus determine the current condition of the blood vessels. The velocity field shows a laminar behavior,where, the velocity is higher in the center of the artery and decreases as the blood flow approaches artery walls. In spite of all artery and blood flow properties not being considered, the values of pressure and velocity obtained are within the normal ranges. Finally the model is used to verify if there exist irregularities in the blood flow in both healthy subjects and sick patients.展开更多
基金the Medical Program of Scientific & Technical Foundation in Xiamen in 2008, No. 3502Z20084028
文摘The optimal velocity encoding of phase-contrast magnetic resonance angiography （PC MRA） in measuring cerebral blood flow volume （BFV） ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional （2D） PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encoding was set to 80 cm/s. Results of the measurements showed that the error rate was 7.0±6.0% in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateral common carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery ＋ external carotid artery and ipsilateral common carotid artery. In addition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore, after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accurate in the determination of BFV in the carotid arteries.
文摘Objective:To systematic evaluation by the dorsalis pedis artery puncture for bed patients blood gas analysis of application effect of impact.Methods:A randomized controlled trial of the effect of arterial blood extraction on blood gas analysis in PubMed,CNKI,Wanfang database and VIP database.After selecting the literature,extracting the data and evaluating the quality of the literature.Meta- analysis was carried out by RevMan 5.3 software.Results:Twelve randomized controlled trials were included and 1696 patients were enrolled.After meta-analysis,the arterial puncture can effectively improve the success of arterial puncture in patients with bed [Z = 5.78,95%CI(1.90,3.66),P<0.001],reduce the occurrence of hematoma [Z = 4.27,95%CI(0.19,0.54),P<0.001],reduce the mistaken into the vein [Z = 4.60,95%CI(0.08,0.36),P<0.001],reduce cyanosis [Z = 2.84,95%CI(0.23,0.81),P<0.008],the difference was statistically significant.Conclusion:Dorsalis pedis artery puncture can improve the success rate of blood gas analysis in bedridden patients,reduce the incidence of hematoma and the incidence of venous leakage,and can be widely used in clinical practice.
文摘This paper presents the development of the blood flow simulation in two dimensions over the real geometry of the femoral artery. The Navier-Stokes equations are solved using the finite element method, to obtain the distributions of the blood pressure and flow velocity in multiple instants of time and different places of the femoral artery and thus determine the current condition of the blood vessels. The velocity field shows a laminar behavior,where, the velocity is higher in the center of the artery and decreases as the blood flow approaches artery walls. In spite of all artery and blood flow properties not being considered, the values of pressure and velocity obtained are within the normal ranges. Finally the model is used to verify if there exist irregularities in the blood flow in both healthy subjects and sick patients.
