Nahrendorf M, Wiesmann F, Hiller K H, Hu K, Waller C, Ruff J, Lanz T E, Neubauer S, Haase A, Ertl G, Bauer W R
Physikalisches Institut (EP5), Universität Würzburg, Germany.
J Magn Reson Imaging. 2001 Nov;14(5):547-55. doi: 10.1002/jmri.1218.
The purpose of the present study was the serial investigation of morphological and functional changes after left coronary artery ligation in the intact rat using cine-magnetic resonance imaging (MRI). MRI studies were performed 4, 8, 12, and 16 weeks after myocardial infarction (MI) with an echocardiogram (ECG)-triggered cine-fast low-angle shot (FLASH)-sequence in a 7-Tesla magnet. MI-size, left ventricular (LV) mass and volumes, cardiac index, ejection fraction (EF), and remote wall and scar thickness of 11 Wistar rats were compared to four sham-operated rats. Stress MRI with dobutamine (10 microl/kg x minute) was performed at 16 weeks. In MI groups (small MI < 30%, N = 5, large MI > 30%, N = 6), there was significant increase of LV mass (small MI + 47.8% increase, large MI + 74.1%) and wall thickness (large MI 1.21 +/- 0.03 to 1.84 +/- 0.07 mm). Scar thickness declined from four to 16 weeks (large MI 0.92 +/- 0.06 to 0.38 +/- 0.02 mm, P < 0.05). End-diastolic volume of both MI groups was significantly elevated but increased further only in animals with large MI from four to 16 weeks (657.1 +/- 38.6 to 869.7 +/- 60.7 microL, P < 0.05). Compared to sham, EF was significantly depressed in MI (large MI 31.5 +/- 2.0%). Wall thickening declined from four to 16 weeks post-MI (large MI 50.9 +/- 9.9 to 28.9 +/- 4.4%, P < 0.05). During stress, sham and MI rats increased wall thickening from 66.5 +/- 8.2 to 111.2 +/- 6.7% and from 30.8 +/- 4.3 to 47.5 +/- 5.8%, respectively (P < 0.05). Hypertrophy was found in all animals with MI throughout the entire period of observation, whereas dilatation after four weeks was only detected in animals with large MI. These morphologic changes were accompanied by an early decline of EF; myocardial function characterized by wall thickening deteriorated later.
本研究的目的是利用电影磁共振成像（MRI）对完整大鼠左冠状动脉结扎后的形态和功能变化进行系列研究。在心肌梗死（MI）后4、8、12和16周，使用超声心动图（ECG）触发的电影快速低角度激发（FLASH）序列，在7特斯拉磁体中进行MRI研究。将11只Wistar大鼠的MI大小、左心室（LV）质量和容积、心脏指数、射血分数（EF）以及远壁和瘢痕厚度与4只假手术大鼠进行比较。在16周时进行多巴酚丁胺（10微克/千克×分钟）负荷MRI检查。在MI组（小MI<30%，N = 5；大MI>30%，N = 6）中，LV质量显著增加（小MI增加47.8%，大MI增加74.1%），壁厚度增加（大MI从1.21±0.03毫米增加到1.84±0.07毫米）。瘢痕厚度从4周降至16周（大MI从0.92±0.06毫米降至0.38±0.02毫米，P<0.05）。两个MI组的舒张末期容积均显著升高，但仅在大MI动物中从4周进一步增加到16周（从657.1±38.6微升增加到869.7±60.7微升，P<0.05）。与假手术组相比，MI组的EF显著降低（大MI为31.5±2.0%）。MI后4至16周壁增厚减少（大MI从50.9±9.9%降至28.9±4.4%，P<0.05）。在负荷状态下，假手术大鼠和MI大鼠的壁增厚分别从66.5±8.2%增加到111.2±6.7%和从30.8±4.3%增加到47.5±5.8%（P<0.05）。在整个观察期内，所有MI动物均出现肥大，而4周后仅在大MI动物中检测到扩张。这些形态学变化伴随着EF的早期下降；以壁增厚为特征的心肌功能在后期恶化。
