PET reversed mismatch in an experimental model of subacute myocardial infarction

• Published in: European Journal of Nuclear Medicine 2001-04, Vol.28 (4), p.457-465
• Main Authors: MESOTTEN, Liesbet, DISPERSYN, Gerrit D, MAES, Alex, ZIETKIEWICZ, Mirek, NUYTS, Johan, BORMANS, Guy, DE GROOT, Tjibbe, BORGERS, Marcel, MORTELMANS, Luc, FLAMENG, Willem
• Format: Article
• Language: English
• Subjects: Acute Disease; Animals; Biological and medical sciences; Cardiology. Vascular system; Coronary Circulation - physiology; Coronary heart disease; Echocardiography; Female; Fluorodeoxyglucose F18; Heart; Heart - diagnostic imaging; Image Processing, Computer-Assisted; Medical sciences; Myocardial Infarction - diagnostic imaging; Myocardial Infarction - metabolism; Myocardial Infarction - physiopathology; Myocardium - metabolism; Radiopharmaceuticals; Sheep; Tomography, Emission-Computed; Ventricular Function, Left
• ISSN: 0340-6997; 1619-7070; 1619-7089
• DOI: 10.1007/s002590000471

The aim of this study was to evaluate the relationship between flow/metabolism, histology and functional follow-up in a sheep model of subacute myocardial infarction. In eight juvenile sheep, a myocardial infarction was induced by intracoronary injection of macrobeads. Left ventricular function was evaluated using echocardiography. 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG)/nitrogen-13-labelled ammonia (13NH3) positron emission tomography (PET) was performed at 6 weeks and 16 weeks after embolization. In five sheep, a dynamic carbon-11 acetate study was performed. In each animal, two regions of interest were defined on the polar map, corresponding to the embolized and the non-embolized region. After the final measurements, the hearts were processed for histological evaluation. PET revealed a moderately decreased flow and oxidative metabolism in the embolized region at 6 weeks, without significant changes at follow-up. At 6 weeks, 18F-FDG uptake in the embolized area was more severely decreased as compared to the flow index in the embolized area (P < 0.05). At 16 weeks, 18F-FDG metabolism had significantly recovered (P < 0.05). Serial echocardiography showed a persistent decrease in global and regional left ventricular function. Histology revealed a mix of micro-infarcted and viable tissue in the embolized region. In this model of subacute myocardial infarction, a PET "reversed mismatch" pattern was observed, with partial recovery of 18F-FDG uptake at follow-up. The histological counterpart of this PET pattern appears to be patchy necrosis.