PET reversed mismatch in an experimental model of subacute myocardial infarction.
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.
Mesotten
L
L
Department of Nuclear Medicine, UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium.
Dispersyn
G D
GD
Maes
A
A
Zietkiewicz
M
M
Nuyts
J
J
Bormans
G
G
de Groot
T
T
Borgers
M
M
Mortelmans
L
L
Flameng
W
W
D000208:Acute Disease; D000818:Animals; D003326:Coronary Circulation / Q000502:physiology; D004452:Echocardiography; D005260:Female; D019788:Fluorodeoxyglucose F18; D006321:Heart / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism; D019275:Radiopharmaceuticals; D012756:Sheep; D014055:Tomography, Emission-Computed; D016277:Ventricular Function, Left
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18