Detection of viable myocardium by low dose dobutamine cine MRI: experimental study in pigs
- Author:
- No author available
- Journal Title:
- CHINESE JOURNAL OF RADIOLOGY
- Issue:
- 8
- DOI:
- 10.3760/j.issn:1005-1201.2002.08.006
- Key Word:
- 磁共振成像,电影;多巴酚丁胺;心肌缺血;动物,实验
Abstract： 目的探讨负荷MR电影鉴别存活心肌的可能性.方法雄性猪10只, 全麻下穿刺股动脉行左室及冠状动脉造影,继而左侧开胸,于回旋支近心段放置外环缩环(ameroid constrictor),拟制成慢性心肌缺血模型.23～57 d后重复左室及冠状动脉造影并分别于静息及多巴酚丁胺负荷试验下(5～20 μg*kg-1*min-1)行MR电影,传统MR电影及屏气法电影相结合,左室短轴多层面(二尖瓣、乳头肌及心尖部)扫描,观察左室各节段运动变化,计算室壁运动积分.完成MR扫描后处死猪,取出心脏即刻切成厚约10 mm左右的左心室短轴切片行氯化三苯基四氮唑(TTC)染色及组织学检查.结果1 只因麻醉意外死亡;1 只左室造影无明显的运动异常,MR及组织学检查亦无明显阳性发现;1 只发生室壁瘤.其余7 只冠状动脉造影均显示左回旋支近段中、重度狭窄(70%～99%),MR电影示左室侧壁及后下壁表现为不同程度的运动障碍,相应的节段室壁运动积分(WMSI):静息缺血区(左室侧壁及后下壁)和正常区(前间隔)分别为(2.27±0.32)分、(1.00±0.00)分(χ2＝106.27,P<0.01); 而缺血区在静息状态下及小剂量多巴酚丁胺(5 μg*kg-1min*-1)时分别为(2.27±0.32)分、(1.40±0.39)分(χ2＝20.57,P<0.01); 进一步比较缺血区静息和给予10或20 μg*kg-1*min-1多巴酚丁胺时的室壁运动积分,其差异均无显著性意义(χ2=3.25 、2.33, P>0.05),后2种剂量的室壁运动积分分别为(1.70±0.76)分、(1.75±0.83)分.组织学检查显示缺血区有不同程度的存活心肌.结论小剂量多巴酚丁胺(5 μg*kg-1*min-1)能增加缺血区心肌收缩力,因此MR电影结合多巴酚丁胺负荷试验能够预测心肌缺血后的活力.
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