Clinical Study Of ¹⁸F-NaF PET/CT Combined With HR-VWI For The Evaluation Of Vulnerable Carotid Plaque

Part Ⅰ The correlation between ¹⁸F-NaF uptake and vulnerability characteristics of carotid plaqueObjective:Patients with atherosclerosis at carotid bifurcation underwent ¹⁸F-sodium fluoride positron emission tomography/computed tomography(¹⁸F-NaF PET/CT)and high-resolution vessel wall imaging（HR-VWI）simultaneously.To explore the correlation between plaque ¹⁸F-NaF uptake and plaque vulnerability characteristics in order to evaluate the efficacy of ¹⁸F-NaF PET/CT in identifying unstable plaques.Methods:Patients of Carotid endarterectomy（CEA）diagnosed with atherosclerosis at Carotid artery bifurcations admitted to the Neurosurgery Department of The Affiliated Hospital of Inner Mongolia Medical University from the beginning of December 2020 to the end of December 2021 were selected for HR-VWI examination.The vulnerability characteristics of plaque were quantitatively analyzed by MR-VPD software,including the volume and fraction of plaque components,rupture of fibrous cap,plaque load and vascular stenosis rate.¹⁸F-NaF PET/CT examination was performed within one week.According to the amount of ¹⁸F-NaF uptake by carotid plaque,patients were divided into ¹⁸F-NaF positive group and¹⁸F-NaF negative group.The difference of plaque vulnerability between groups was analyzed for statistical significance.Results:A total of 31 patients were included in this study,including 23 patients with bilateral carotid artery plaque at bifurcation,and the remaining 8 patients with unilateral carotid artery plaque.Among 54 carotid arteries with atherosclerosis,33carotid arteries were ¹⁸F-NaF positive and 21 carotid arteries were ¹⁸F-NaF negative.The statistical results are as follows:1.The volume and percentage of lipid-rich necrotic core（LRNC）and intraplaque hemorrhage（IPH）in ¹⁸F-NaF positive plaques were larger than those in ¹⁸F-NaF negative plaques,P<0.05.2.the proportion of fiber cap rupture（FCR）in ¹⁸F-NaF positive plaques was higher than that in ¹⁸F-NaF negative plaques,P<0.05.3.the plaques with positive ¹⁸F-NaF uptake were more loaded than those with negative ¹⁸F-NaF uptake,P<0.05.4.There was no significant difference in the volume and percentage of calcification（CA）and loose matrix（LM）between ¹⁸F-NaF positive plaque and ¹⁸F-NaF negative plaque,P>0.05.5.There was no significant difference in the rate of vascular stenosis between ¹⁸F-NaF positive plaque and ¹⁸F-NaF negative plaque,P>0.05.Conclusions:The plaques with positive ¹⁸F-NaF uptake are more vulnerable than the plaques with negative ¹⁸F-NaF uptake,and the plaques with positive ¹⁸F-NaF uptake are more unstable.¹⁸F-NaF PET/CT is feasible for the stability detection of carotid plaque,and is expected to be an effective new method for the detection of carotid atherosclerotic plaque.Part Ⅱ Comparative analysis of ¹⁸F-NaF PET/CT and HR-VWI in identifying vulnerable plaques and pathologyObjective: ¹⁸F-sodium fluoride positron emission tomography /computed tomography(¹⁸F-NaF PET/CT)and high-resolution vessel wall imaging（HR-VWI）were performed simultaneously in patients with atherosclerosis at carotid bifurcation before carotid endarterectomy.The identification of vulnerable plaques by the two tests was compared with the "gold standard" pathological findings.To explore the ability of both to identify vulnerable plaques and the ability of both to identify vulnerable plaques.Methods: Patients admitted to the Neurosurgery Department of The Affiliated Hospital of Inner Mongolia Medical University from early December 2020 to the end of December 2021 who were diagnosed with atherosclerosis at carotid artery branch before CEA were selected and underwent ¹⁸F-NaF PET/CT examination and HR-VWI examination within one week.The sensitivity（SE）,specificity（SP）,positive predictive value（PV+）,negative predictive value（PV-）,and diagnosis coincidence rate of the two imaging methods were compared with pathological gold standard.Results: 1.The SE、SP、PV+、PV-and diagnostic coincidence rate of 18 F-NaF PET/CT in identifying vulnerable plaques were 73.08% 80.00% 95.00% 36.36% 74.19% and the AUC was 0.765.2.HR-VWI in diagnosing vulnerable plaques was 84.62%、60%、88%、50%、80.65%（same order as above）.AUC is 0.723.3.The results of the combined diagnosis of vulnerable plaque were 92.31%、80%、96%、66.67%、90.03%（same order as above）.AUC was 0.774.Conclusion: 1.The diagnostic coincidence rate of HR-VWI was higher than that of¹⁸F-NaF PET/CT.2.¹⁸F-NaF PET/CT had higher specificity and positive predictive value.3.The coincidence rate and AUC of HR-VWI and ¹⁸F-NaF PET/CT combined diagnosis are higher than HR-VWI and ¹⁸F-NaF PET/CT alone.4.¹⁸F-NaF PET/CT and HR-VWI are both effective imaging methods for vulnerable plaques.The combination of the two has the potential to be an ideal noninvasive imaging protocol for the detection of vulnerable plaques in the future.