Dulce M C, Duerinckx A J, Hartiala J, Caputo G R, O'Sullivan M, Cheitlin M D, Higgins C B
Department of Radiology, University of California, Medical School, San Francisco 94134.
AJR Am J Roentgenol. 1993 May;160(5):963-70. doi: 10.2214/ajr.160.5.8470611.
Gadodiamide injection (Omniscan, Sanofi Winthrop Pharmaceuticals, New York) is a new nonionic MR contrast medium that has been shown in animal studies to provide persistent differential enhancement of myocardial infarction. Because differential enhancement of normal and infarcted myocardium may be useful for the diagnosis and sizing of myocardial infarctions, we assessed the effectiveness of gadodiamide injection in enhancing signal-intensity differences between infarcted and normal myocardium on spin-echo T1-weighted images.
Signal intensity of normal and infarcted myocardium, contrast ratio, contrast-to-noise ratio, and signal-to-noise ratio were measured in 12 patients with subacute myocardial infarction (mean, 16 days after diagnosis) before and after injection of contrast medium. Precontrast T1-weighted and T2-weighted images were obtained with a 1.5-T MR imager. T1-weighted images were acquired 5, 15, and 30 min after gadodiamide injection (0.2 mmol/kg) and T1-weighted images with fat saturation were acquired 10 min after gadodiamide injection.
Gadodiamide injection significantly increased signal intensity of normal (34 +/- %) and infarcted (90 +/- %) myocardium compared with their signal intensities on precontrast T1-weighted images. The contrast ratio was significantly increased, and the augmented ratios persisted throughout the 45-min observation period. The contrast ratio on T2-weighted images was comparable to that on contrast-enhanced T1-weighted images (with or without the use of fat saturation). However, the signal-to-noise and contrast-to-noise ratios of T2-weighted images were significantly lower than those of contrast-enhanced T1-weighted images. The maximum contrast-to-noise ratio for visualizing myocardial infarction was achieved on contrast-enhanced T1-weighted images with fat saturation.
Improved and persistent contrast between infarcted and normal myocardium can be produced on MR images by injecting gadodiamide at a dose of 0.2 mmol/kg, which provides prolonged delineation of myocardial infarctions. Maximum contrast-to-noise ratios for detecting myocardial infarction can be produced by using fat-saturated T1-weighted imaging after a high dose of this nonionic contrast medium has been administered.
钆喷酸葡胺注射液（欧乃影，赛诺菲·温思罗普制药公司，纽约）是一种新型非离子型磁共振造影剂，动物研究表明其可使心肌梗死呈现持续的差异强化。鉴于正常心肌与梗死心肌的差异强化可能有助于心肌梗死的诊断及大小评估，我们评估了钆喷酸葡胺注射液在自旋回波T1加权图像上增强梗死心肌与正常心肌信号强度差异的效果。
对12例亚急性心肌梗死患者（诊断后平均16天）注射造影剂前后的正常心肌与梗死心肌信号强度、对比率、对比噪声比及信噪比进行测量。使用1.5-T磁共振成像仪获取注射造影剂前的T1加权和T2加权图像。注射钆喷酸葡胺（0.2 mmol/kg）后5、15和30分钟获取T1加权图像，注射钆喷酸葡胺10分钟后获取脂肪饱和T1加权图像。
与注射造影剂前T1加权图像上的信号强度相比，钆喷酸葡胺注射液显著提高了正常心肌（34±%）和梗死心肌（90±%）的信号强度。对比率显著增加，且在整个45分钟观察期内增强比率持续存在。T2加权图像上的对比率与对比增强T1加权图像（使用或不使用脂肪饱和）相当。然而，T2加权图像的信噪比和对比噪声比显著低于对比增强T1加权图像。在脂肪饱和的对比增强T1加权图像上可实现观察心肌梗死的最大对比噪声比。
以0.2 mmol/kg的剂量注射钆喷酸葡胺可在磁共振图像上产生梗死心肌与正常心肌之间改善且持续的对比，从而对心肌梗死进行长时间的描绘。在给予这种高剂量非离子型造影剂后使用脂肪饱和T1加权成像可产生检测心肌梗死的最大对比噪声比。
