Evaluation of carotid artery plaque stability with ¹⁸F-FDG PET/CT and contrast-enhanced ultrasonography]

To assess the value of contrast-enhanced ultrasonography (CEUS) and fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) in evaluating the stability of carotid atherosclerosis.Seventeen patients with 21 carotid artery plaques received examinations with CEUS. According to the nature of the plaques, the patients were divided into soft and mixed plaque group and hard and calcified plaque group. The maximal enhancement intensity of the plaques (I(MAX)) and maximal plaque density (D(MAX)) were measured to quantify the neovasculature. The patients also underwent concurrent ¹⁸F-FDG PET/CT, and ¹⁸F-FDG uptake was quantified by the mean standard uptake values (SUV(mean)), an index reflecting the inflammatory activity in the plaque. The findings in CEUS and PET/CT were comparatively analyzed for these cases.The D(MAX) of the plaque in soft and mixed plaque group was significantly greater than that in hard and calcified plaque group (4.26±3.65 vs 1.41±1.47, P<0.05); the I(MAX) was also greater in the former group, but this difference was not statistically significant (26.83±19.61 vs 24.73±29.85, P=0.869). The soft and mixed plaques tended to have higher SUVmean than the hard and calcified plaques (1.70±0.45 vs 1.47±0.12, P=0.099). The values of I(MAX) and D(MAX) were not found to correlate to SUV(mean) in these patients.CEUS can sensitively show the status of neovascularization within the carotid atherosclerosis plaques, and PET/CT reflects the inflammatory activity in the plaques. The combination of these two imaging modalities allows the evaluation of plaque stability in terms of neoangiogenesis and inflammatory activity.