Marchal G, Ni Y, Herijgers P, Flameng W, Petré C, Bosmans H, Yu J, Ebert W, Hilger C S, Pfefferer D, Semmler W, Baert A L
Department of Radiology, University Hospitals K.U. Leuven, Belgium.
Eur Radiol. 1996;6(1):2-8. doi: 10.1007/BF00619942.
In previous experiments in tumors we demonstrated that metalloporphyrins are particularly avid for nonviable tumor components. This study was performed to find out whether these agents can be used as MRI contrast agents for the visualization of acute myocardial infarction (MI). A total of 44 rats, 6 normal controls and 38 with occlusive MI (2-24 h old), were used. Gadolinium mesoporphyrin (Gd-MP) or manganese tetraphenylporphyrin (Mn-TPP) was intravenously injected at doses of 0.1, 0.05, and 0.01 mmol/kg. Three to 24 h after injection, axial and coronal T1-weighted (TR/TE 300/15 ms) spin-echo MR images were obtained before and after killing the animals and correlated with triphenyl tetrazolium chloride (TTC) histochemical preparations. The Gd-MP content in infarcted and noninfarcted myocardium was measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES). MRI without contrast media could not discern the MI. However, 3-24 h after injection of either Gd-MP or Mn-TPP, the infarcted area was positively stained on MR images. This area matched well with the negatively TTC-stained area on the heart slices (r = 0.97). The contrast ratios between the infarcted necrotic myocardium and the noninfarcted regions varied from 150 to 300% depending on the type of agents and doses used. Neither false-positive nor false-negative findings were encountered. The metalloporphyrin concentration was more than 10 times higher in the infarcted than in the noninfarcted heart. Metalloporphyrins appear to be promising MRI contrast agents for detection and quantification of necrosis in MI. These preclinical results may open new perspectives in cardiac imaging.
在先前的肿瘤实验中，我们证明金属卟啉对无活力的肿瘤成分具有特别高的亲和力。本研究旨在探究这些试剂是否可用作磁共振成像（MRI）造影剂以可视化急性心肌梗死（MI）。总共使用了44只大鼠，其中6只为正常对照，38只患有闭塞性MI（发病2 - 24小时）。以0.1、0.05和0.01 mmol/kg的剂量静脉注射钆中卟啉（Gd - MP）或四苯基卟啉锰（Mn - TPP）。注射后3至24小时，在处死动物前后获取轴向和冠状面T1加权（TR/TE 300/15 ms）自旋回波MR图像，并与氯化三苯基四氮唑（TTC）组织化学制剂进行对比。使用电感耦合等离子体原子发射光谱法（ICP - AES）测量梗死心肌和非梗死心肌中的Gd - MP含量。无造影剂的MRI无法辨别MI。然而，注射Gd - MP或Mn - TPP后3至24小时，梗死区域在MR图像上呈阳性染色。该区域与心脏切片上TTC阴性染色区域匹配良好（r = 0.97）。根据所用试剂类型和剂量，梗死坏死心肌与非梗死区域之间的对比率在150%至300%之间。未出现假阳性或假阴性结果。梗死心脏中的金属卟啉浓度比非梗死心脏高10倍以上。金属卟啉似乎是用于检测和定量MI坏死的有前景的MRI造影剂。这些临床前结果可能为心脏成像开辟新的前景。
