To investigate the value of ¹⁸F-FDG PET/CT myocardial inflammation imaging in evaluating the functional prognosis of left ventricle (LV) in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI).

Thirty-one patients (26 males, 5 females, age: (55.4±10.1) years) with acute ST-elevation myocardial infarction (STEMI) referred for PCI in Beijing Chaoyang Hospital between January 2016 and December 2016 were prospectively included. All patients underwent ¹⁸F-FDG PET/CT following ⁹⁹Tc^m-methoxyisobutylisonitrile (MIBI) rest myocardial perfusion imaging (MPI) on the fifth day after PCI. A comprehensive strategy recommended by guideline was followed to suppress myocardial uptake. ¹⁸F-FDG uptake in infarcted and remote myocardium were quantitatively analyzed by measuring SUV_max, and that in superior vena cava was quantitatively analyzed by measuring SUV_mean. Target-to-background ratios (TBRs) in infarcted and remote area were calculated. In addition, the following parameters were obtained: ¹⁸F-FDG uptake volume of LV (Vol-FDG), percentage of ¹⁸F-FDG uptake size of LV (F/LV%) , percentage of myocardial perfusion defect size of LV (def/LV%). According to the left ventricular ejection fraction (EF) at baseline and 6 months after AMI, the changing rate of EF (ΔEF) was calculated, and data of patients in improvement group (ΔEF≥10%) and no improvement group (ΔEF<10%) were compared. Independent-sample t test or Mann-Whitney U test, and Pearson correlation analysis or Spearman rank correlation analysis were used for data analysis.

TBR was significantly higher in infarcted myocardium than that in remote area (2.8±1.0 vs 1.1±0.3; t=11.03, P<0.001). F/LV% was greater than def/LV% (33.7%(25.8%, 43.3%) vs 8.8%(2.3%, 20.7%); z=-4.72, P<0.001). TBR in both infarcted and remote areas showed positive correlations with peripheral blood monocyte counts (r=0.44, P=0.014; r=0.37, P=0.042). Vol-FDG had positive correlations with the myocardial injury markers (creatine kinase (CK), CK isoenzyme (CK-MB), cardiac troponin I (cTnI); r values: 0.46, 0.41, 0.68, all P<0.05). Of the 31 patients, 26(83.9%) completed the 6-month follow-up. Vol-FDG in no improvement group (n=11) was significantly greater than that in improvement group (n=15; (104.5±47.2) vs (70.1±26.3) cm^3;t=2.38, P=0.026). There was a negative correlation between Vol-FDG and ΔEF (r_s=-0.41, P=0.038).

¹⁸F-FDG PET/CT imaging can evaluate the intensity and size of myocardial inflammation, and estimate the functional prognosis of LV in patients with AMI undergoing PCI.

Myocardial infarction; Ventricular function, left; Inflammation; Positron-emission tomography; Tomography, X-ray computed; Fluorodeoxyglucose F18