Characterization of viable and nonviable myocardium at MR imaging: comparison of gadolinium-based extracellular and blood pool contrast materials versus manganese-based contrast materials in a rat myocardial infarction model.

Autor:	Flacke S; Center for Cardiovascular Magnetic Resonance, Department of Medicine, Cardiovascular Division, Washington University Medical School, St Louis, MO, USA. flacke@uni-bonn.de, Allen JS, Chia JM, Wible JH, Periasamy MP, Adams MD, Adzamli IK, Lorenz CH
Jazyk:	angličtina
Zdroj:	Radiology [Radiology] 2003 Mar; Vol. 226 (3), pp. 731-8. Date of Electronic Publication: 2003 Jan 24.
DOI:	10.1148/radiol.2263020151
Abstrakt:	Purpose: To determine the contrast agent behavior of gadolinium-based (extracellular and albumin-binding) and manganese-based contrast media for late-enhancement imaging of myocardial infarction. Materials and Methods: Coronary ligation was performed in 30 rats, and they were serially imaged with segmented inversion-recovery gradient-echo magnetic resonance (MR) imaging (repetition time msec/echo time msec/inversion time msec [fixed], 5.2/2.5/430; flip angle, 15 degrees ) during 1 hour after administration of contrast media by using a 1.5-T MR unit. Serial measurements of the longitudinal relaxation were performed by using the Look-Locker approach (repetition time msec/echo time msec, 1,000/3.5; flip angle, 10 degrees ). Detection and size of infarction were evaluated at each time point and compared with end-point histologic findings. Results: For all manganese-based media, the contrast agent cleared from the blood pool rapidly. Manganese-based contrast media allowed precise labeling of viable cardiomyocytes within 30 minutes, and the labeling persisted for at least 1 hour. Accumulation of gadoversetamide in the infarct area was apparent after 5 minutes, and the peak contrast-to-noise ratio (CNR) between infarct and myocardium was comparable to the peak CNR of manganese-based contrast agents. Extracellular gadopentetate dimeglumine provided excellent infarct detection but a small imaging window for precise sizing of the infarct if a fixed inversion time of 430 msec was used. Albumin-binding gadolinium-based contrast media provided a longer imaging window, but infarct size was overestimated because of the nonspecific distribution of the unbound gadolinium agent. Conclusion: When extracellular gadolinium-based agents are used for infarct size measurement, imaging parameters and timing are important because the kinetics of both normal and irreversibly injured myocardium must be considered. Manganese-based agents are highly specific and less sensitive to timing for infarct size determination, but further studies are required to determine if they are feasible for human use.
Databáze:	MEDLINE
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