PET reversed mismatch in an experimental model of subacute myocardial infarction

Eur J Nucl Med. 2001 Apr;28(4):457-65. doi: 10.1007/s002590000471.

Abstract

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.

MeSH terms

  • Acute Disease
  • Animals
  • Coronary Circulation / physiology
  • Echocardiography
  • Female
  • Fluorodeoxyglucose F18
  • Heart / diagnostic imaging
  • Image Processing, Computer-Assisted
  • Myocardial Infarction / diagnostic imaging*
  • Myocardial Infarction / metabolism
  • Myocardial Infarction / physiopathology
  • Myocardium / metabolism
  • Radiopharmaceuticals
  • Sheep
  • Tomography, Emission-Computed
  • Ventricular Function, Left

Substances

  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18