Ventilation-synchronous magnetic resonance microscopy of pulmonary structure and ventilation in mice
Ventilation-synchronous magnetic resonance microscopy of pulmonary structure and ventilation in mice
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DOI：
10.1002/mrm.20307
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Johnson, GA
中科院分区：
文献类型：
--
作者：
Chen, BT;Yordanov, AT;Johnson, GA
越来越多地使用转基因动物模型来治疗肺部疾病，这增加了对评估生理稳定小鼠肺部结构和功能的方法的需求。我们在这里报告使用磁共振显微镜与钆 (Gd) 标记的星爆树枝状聚合物 (G6-1B4M-Gd，MW = 192 +/- 1 kDa，R-h = 5.50 +/- 0.04 nm) 和超极化 3 氦 (He-3) 气体的集成协议，以获取显示活体小鼠 (n = 9) 肺脉管系统和通气气道的图像。 H-1 和 He-3 的配准三维图像是在 2.0 T 屏气期间使用径向采集获得的（总采集时间分别为 38 分钟和 25 分钟）。大分子Gd标记的树枝状聚合物（半衰期约为80分钟）使左心室的信噪比增加了81 +/- 30%，肺周围的信噪比增加了43 +/- 22%，胸壁的信噪比增加了-4 +/- 5%，从而增加了这些结构相对于血管较少的周围组织的对比度。为小鼠开发了恒流呼吸机，以在成像过程中输送 O-2 和 N-2（或 He-3）的各种气体混合物。为了避免低氧血症，仪器死腔被最小化，并对气体压缩导致的潮气量损失进行了修正。通过缺乏自主呼吸和维持恒定心率来评估生理支持的稳定性。使用 105 次呼吸/分钟和类似于 0.2 毫升/呼吸的通气，我们能够稳定小鼠超过 8 小时。在小鼠肺中证明了获取肺脉管系统和通气气道的可行性，面内空间分辨率为 70 x 70 mum(2)，切片厚度为 800 mum。 (C) 2004Wiley-Liss, Inc.
Increasing use of transgenic animal models for pulmonary disease has raised the need for methods to assess pulmonary structure and function in a physiologically stable mouse. We report here an integrated protocol using magnetic resonance microscopy with gadolinium (Gd)-labeled starburst dendrimer (G6-1B4M-Gd, MW = 192 +/- 1 kDa, R-h = 5.50 +/- 0.04 nm) and hyperpolarized 3 helium (He-3) gas to acquire images that demonstrate pulmonary vasculature and ventilated airways in live mice (n = 9). Registered three-dimensional images of H-1 and He-3 were acquired during breath-hold at 2.0 T using radial acquisition (total acquisition time of 38 and 25 min, respectively). The macromolecular Gd-labeled dendrimer (a half-life of similar to80 min) increased the signal-to-noise by 81 +/- 30% in the left ventricle, 43 +/- 22% in the lung periphery, and -4 +/- 5% in the chest wall, thus increasing the contrast of these structures relative to the less vascular surrounding tissues. A constant-flow ventilator was developed for the mouse to deliver varied gas mixtures of O-2 and N-2 (or He-3) during imaging. To avoid hypoxemia, instrumental dead space was minimized and corrections were made to tidal volume lost due to gas compression. The stability of the physiologic support was assessed by the lack of spontaneous breathing and maintenance of a constant heart rate. We were able to stabilize the mouse for >8 hr using ventilation of 105 breath/min and similar to0.2 mL/breath. The feasibility of acquiring both pulmonary vasculature and ventilated airways was demonstrated in the mouse lung with inplane spatial resolution of 70 x 70 mum(2) and slice thickness of 800 mum. (C) 2004Wiley-Liss, Inc.