Short-Term Changes in Carotid Artery Inflammation Measured by Positron Emission Tomography are Associated With Long Term Atherosclerosis Progression Measured by Magnetic Resonance Imaging

Introduction: It is unknown whether short-term changes arterial wall inflammation are associated with changes in the rate of structural progression of atherosclerosis. Hypothesis: We assessed arterial inflammation, using positron emission tomography (PET) imaging and 18F-fluorodeoxyglucose (FDG) to test the hypothesis that short term changes in arterial inflammation predict long term atherosclerosis progression, measured by magnetic resonance imaging( MRI). Methods: Forty-two participants enrolled in the dal-PLAQUE study , who underwent both PET and MRI imaging of the carotid arteries were evaluated. Short-term change in arterial inflammation was measured as change in the carotid FDG target to background ratio [TBR] by PET between baseline and 6 months. The long-term rate of atherosclerotic plaque progression was assessed using MRI, as percent change in carotid mean wall area [MWA] and mean wall thickness [MWT] between baseline and 24 months. Results: The mean age of the population was 62.5 years, and 12 (28.6 %) were male. In participants with (vs. without) any increase in arterial inflammation over 6 months, long-term rate of change in MWT was significantly higher (% change MWT: 17.49% vs. 1.74%, p=0.038) and long-term rate of change in MWA was significantly higher (% change MWA: 25.50% vs. 3.59%, p = 0.027). Results remained significant after adjusting for clinical and biochemical covariates. Individuals with no increase in arterial inflammation over 6 months had no significant structural progression of atherosclerosis over 24 months, measured as MWT (p=0.616) or MWA (p=0.373). Conclusions: Short-term changes in arterial inflammation predict long-term atherosclerosis progression. In those with no increase in arterial inflammation, no significant changes in atherosclerosis progression were observed.