An apparent unidirectional influx constant for manganese as a measure of myocardial calcium channel activity
An apparent unidirectional influx constant for manganese as a measure of myocardial calcium channel activity
复制标题
DOI：
10.1002/jmri.20736
复制
发表时间：
2006-11-01
影响因子：
4.4
通讯作者：
Larsson, Henrik B. W.
中科院分区：
文献类型：
--
作者：
Skjold, Arne;Kristoffersen, Anders;Larsson, Henrik B. W.
目的：建立一种通过定量二磷酸二吡哆基锰（MnDPDP）输注后表观单向锰内流常数来评估心肌钙通道活性的体内磁共振方法。材料与方法：将10名健康志愿者分为两组，分别在1.5特斯拉扫描仪上静脉注射5 μ mol / kg体重的MnDPDP，时间为5分钟或30分钟。快速反演恢复梯度回波序列用于估计对比前和对比后的R值，并测量注射后的信号变化。假设造影剂在所有组织间室的纵向松弛度（r(1)）相等，血液和心肌组织的信号变化分别得到时间输入和组织造影剂浓度。通过双组织室模型，估计心肌锰积累的表观单向内流常数（K-i）。结果：左室壁K-i值一致，平均值为5.96 mL/100 g/min （SD = 0.49; N = 10）。两组患者K-i水平差异无统计学意义。结论：由于单向锰积累依赖于完整的肌细胞膜和功能正常的钙通道，使用单向锰内流速率可能是心肌疾病中肌细胞功能体内研究的一种有价值的研究工具。
Purpose: To develop an in vivo MR method for evaluation of myocardial calcium channel activity through quantification of apparent unidirectional manganese influx constants following manganese dipyridoxyl-diphosphate (MnDPDP) infusions.Materials and Methods: A total of 10 healthy volunteers were divided in two groups, and received 5 mu mol of MnDPDP per kg of body weight intravenously in a 1.5 Tesla scanner over five or 30 minutes, respectively. A fast inversion recovery gradient echo sequence was used to estimate pre- and postcontrast R, values and, to measure signal changes following infusions. By assuming equal longitudinal relaxivity (r(1)) of the contrast in all tissue compartments, signal changes in blood and myocardial tissue yielded temporal input and tissue contrast concentrations respectively. Through a two-tissue compartment model, apparent unidirectional influx constants (K-i) for myocardial manganese accumulation were estimated.Results: Consistent values for K-i in left ventricular wall were found, with a mean value of 5.96 mL/100 g/minute (SD = 0.49; N = 10). No statistical significant differences in K-i were found between the two infusion groups.Conclusion: Since unidirectional manganese accumulation depends upon intact myocyte membranes with functioning calcium channels, the use of unidirectional manganese influx rates may be a valuable research tool for in vivo studies of myocyte functioning in myocardial disease.