18F-fluoride positron emission tomography for identification of ruptured and high-risk coronary atherosclerotic plaques: a prospective clinical trial
fluoride positron emission tomography for identification of ruptured and high-risk coronary atherosclerotic plaques: a prospective clinical trial ' The Lancet, vol 383, no. 9918, Summary Background The use of non-invasive imaging to identify ruptured or high-risk coronary atherosclerotic plaques would represent a major clinical advance for prevention and treatment of coronary artery disease. We used combined PET and CT to identify ruptured and high-risk atherosclerotic plaques using the
... s using the radioactive tracers ¹⁸F-sodium fl uoride (¹⁸F-NaF) and ¹⁸F-fl uorodeoxyglucose (¹⁸F-FDG). Methods In this prospective clinical trial, patients with myocardial infarction (n=40) and stable angina (n=40) underwent ¹⁸F-NaF and ¹⁸F-FDG PET-CT, and invasive coronary angiography. ¹⁸F-NaF uptake was compared with histology in carotid endarterectomy specimens from patients with symptomatic carotid disease, and with intravascular ultrasound in patients with stable angina. The primary endpoint was the comparison of ¹⁸F-fl uoride tissue-tobackground ratios of culprit and non-culprit coronary plaques of patients with acute myocardial infarction. Findings In 37 (93%) patients with myocardial infarction, the highest coronary ¹⁸F-NaF uptake was seen in the culprit plaque (median maximum tissue-to-background ratio: culprit 1·66 [IQR 1·40-2·25] vs highest non-culprit 1·24 [1·06-1·38], p<0·0001). By contrast, coronary ¹⁸F-FDG uptake was commonly obscured by myocardial uptake and where discernible, there were no diff erences between culprit and non-culprit plaques (1·71 [1·40-2·13] vs 1·58 [1·28-2·01], p=0·34). Marked ¹⁸F-NaF uptake occurred at the site of all carotid plaque ruptures and was associated with histological evidence of active calcifi cation, macrophage infi ltration, apoptosis, and necrosis. 18 (45%) patients with stable angina had plaques with focal ¹⁸F-NaF uptake (maximum tissue-to-background ratio 1·90 [IQR 1·61-2·17]) that were associated with more high-risk features on intravascular ultrasound than those without uptake: positive remodelling (remodelling index 1·12 [1·09-1·19] vs 1·01 [0·94-1·06]; p=0·0004), microcalcifi cation (73% vs 21%, p=0·002), and necrotic core (25% [21-29] vs 18% [14-22], p=0·001). Interpretation ¹⁸F-NaF PET-CT is the fi rst non-invasive imaging method to identify and localise ruptured and highrisk coronary plaque. Future studies are needed to establish whether this method can improve the management and treatment of patients with coronary artery disease. Funding Chief Scientist Offi ce Scotland and British Heart Foundation.