Determinants of Extraaortic Arterial 18F-FDG Accumulation in Asymptomatic Cohorts: Sex Differences in the Association with Cardiovascular Risk Factors and Coronary Artery Stenosis

The objective of this study was to evaluate extraaortic arterial 18F-FDG accumulation in asymptomatic cohorts by sex and to clarify the association between extraaortic arterial 18 F-FDG accumulation and cardiovascular risk factors (CRFs) and coronary artery stenosis (CAS). Methods: Five hundred twenty-one asymptomatic individuals (351 men and 170 women) who underwent cancer and CAS screening were enrolled. We evaluated extraaortic arterial 18 F-FDG accumulation in the carotid artery (CA) and iliofemoral artery (IFA) and classified the accumulation patterns into 3 types. Type 1 patients had no extraaortic arterial 18F-FDG accumulation, type 2 had accumulation in either the CA or the IFA, and type 3 had accumulation in both the CA and IFA. CRFs (age, low-density lipoprotein [LDL] and high-density lipoprotein [HDL] cholesterol, triglyceride concentration, visceral abdominal fat, hypertension, diabetes, and smoking) and significant CAS were examined in relation to each accumulation type. Results: The men showed more extensive extraaortic arterial 18 F-FDG accumulation than the women. Type 3 accumulation (60.4% vs. 37.1%, P , 0.0001) was more frequently observed in men, whereas type 2 (34.2% vs. 44.7%, P 5 0.02) and type 1 (5.4% vs. 18.2%, P , 0.0001) accumulation were more frequent in women. The CRFs other than smoking tended to be worse with extensive extraaortic arterial 18F-FDG accumulation. A multivariate logistic regression analysis showed that hypertension, age, LDL cholesterol, triglyceride, and visceral abdominal fat were significantly associated with type 3 accumulation in men, and LDL cholesterol and HDL cholesterol (inversely) were significantly associated with type 3 accumulation in women. CAS was found in 4.2% (9/212) of male patients and in 1.6% (1/63) of female patients with type 3 accumulation, whereas no CAS was found in the other 2 types. Conclusion: The men showed more extensive extraaortic arterial 18 F-FDG accumulation than the women. LDL cholesterol was associated with extensive extraaortic arterial 18F-FDG accumulation in both sexes, but the other CRFs associated with extensive extraaortic 18 F-FDG arterial accumulation differed between the sexes. The type 3 accumulation was considered to pose a risk of CAS, especially in male patients, whereas non–type 3 accumulation presented little risk.