Observation of flow distribution pattern in the hemodialyzers is significant as it is a valuable in-dication of the performance of these modules. Therefore, in this study, a feasible non-destructive Magnetic Resonance...Observation of flow distribution pattern in the hemodialyzers is significant as it is a valuable in-dication of the performance of these modules. Therefore, in this study, a feasible non-destructive Magnetic Resonance Imaging (MRI) technique is proposed to characterize the flow distribution in the blood compartment of hemodialyzers using Gd-DTPA MRI contrast agent. The distribution of flow is qualitatively observed in two commercial clinical dialyzers through an in-vitro experiment. The contrast enhanced T1 weighted images are acquired along the dialyzer length using Spin Echo (SE) pulse sequence after an injection of 0.5 mmol/L Gd-DTPA solution into the blood compartment. Although relatively uniform flow distribution pattern over the spatial volume of transverse images, close the dialyzer inlet is observed, the heterogeneity of flow distribution can be identified towards the blood outlet port. Furthermore, the signal intensity profiles formed by the injected Gd-DTPA are gradually decreased towards the outlet port. These results of the study suggest that although no advanced techniques and protocols available, MRI and Gd-DTPA contrast agent can be utilized to characterize the flow distribution within a dialyzer qualitatively.展开更多
The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_...The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_ i =10.90,8.50,4.55,2.92,2.20) and the stability constant for GdL 2- (lg K _ GdL 2- =22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA,respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).展开更多
文摘Observation of flow distribution pattern in the hemodialyzers is significant as it is a valuable in-dication of the performance of these modules. Therefore, in this study, a feasible non-destructive Magnetic Resonance Imaging (MRI) technique is proposed to characterize the flow distribution in the blood compartment of hemodialyzers using Gd-DTPA MRI contrast agent. The distribution of flow is qualitatively observed in two commercial clinical dialyzers through an in-vitro experiment. The contrast enhanced T1 weighted images are acquired along the dialyzer length using Spin Echo (SE) pulse sequence after an injection of 0.5 mmol/L Gd-DTPA solution into the blood compartment. Although relatively uniform flow distribution pattern over the spatial volume of transverse images, close the dialyzer inlet is observed, the heterogeneity of flow distribution can be identified towards the blood outlet port. Furthermore, the signal intensity profiles formed by the injected Gd-DTPA are gradually decreased towards the outlet port. These results of the study suggest that although no advanced techniques and protocols available, MRI and Gd-DTPA contrast agent can be utilized to characterize the flow distribution within a dialyzer qualitatively.
文摘The present paper covers the synthesis and the characterization of ligand 2-decyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid,H_5L,and its Gd(Ⅲ) chelate. The protonation constants for H_5L(lg K H_ i =10.90,8.50,4.55,2.92,2.20) and the stability constant for GdL 2- (lg K _ GdL 2- =22.80) were determined by means of potentiometric titration. They are similar to the corresponding values of DTPA and Gd-DTPA,respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after the introduction of a linear chain decyl group into the terminal acetic acid residue of DTPA. The Gd(Ⅲ) chelate may be a potential contrast agent with liver-specificity for magnetic resonance imaging(MRI).
