Schneider Jürgen E, Cassidy Paul J, Lygate Craig, Tyler Damian J, Wiesmann Frank, Grieve Stuart M, Hulbert Karen, Clarke Kieran, Neubauer Stefan
Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom.
J Magn Reson Imaging. 2003 Dec;18(6):691-701. doi: 10.1002/jmri.10411.
To establish fast, high-resolution in vivo cine magnetic resonance imaging (cine-MRI) on a vertical 11.7-T MR system and to investigate the stability of normal and failing mouse hearts in the vertical position.
To optimize the method on a high-field system, various MR-related parameters, such as relaxation times and the need for respiratory gating, were quantitatively investigated. High-resolution cine-MRI was applied to normal mice and to a murine heart failure model. Cardiac functional parameters were compared to matched mice imaged previously on a horizontal MR system.
A T(1) of 1.10 +/- 0.27 seconds and a T(2) of 18.5 +/- 3.9 msec were measured for murine myocardial tissue. A quantitative analysis also proved respiratory gating to be essential for obtaining artifact-free cine images in the vertical position at this field strength. Cardiac functional parameters of mice, obtained within one hour, agreed well with those from previous studies of mice in the horizontal position.
This work shows that MR systems with a vertical bore design can be used to accurately measure cardiac function in both normal and chronically failing mouse hearts within one hour. The increased signal-to-noise ratio (SNR) due to the higher field strength could be exploited to obtain higher temporal and spatial resolution compared to previous studies that were performed on horizontal systems with lower field strengths.
在垂直孔径11.7-T磁共振(MR)系统上建立快速、高分辨率的活体电影磁共振成像(cine-MRI),并研究正常和衰竭小鼠心脏在垂直位的稳定性。
为在高场系统上优化该方法,对各种与MR相关的参数进行了定量研究,如弛豫时间和呼吸门控的必要性。将高分辨率cine-MRI应用于正常小鼠和小鼠心力衰竭模型。将心脏功能参数与先前在水平MR系统上成像的匹配小鼠进行比较。
测得小鼠心肌组织的T(1)为1.10±0.27秒,T(2)为18.5±3.9毫秒。定量分析还证明,在该场强下,呼吸门控对于在垂直位获得无伪影的cine图像至关重要。在一小时内获得的小鼠心脏功能参数与先前对水平位小鼠的研究结果吻合良好。
本研究表明,具有垂直孔径设计的MR系统可用于在一小时内准确测量正常和慢性衰竭小鼠心脏的功能。与先前在低场强水平系统上进行的研究相比,由于更高的场强而增加的信噪比(SNR)可用于获得更高的时间和空间分辨率。