Involvement of Iliofemoral Arteries in PET/CT Is Associated with Atherosclerotic Risk Factors in Takayasu’s Arteritis

<b>Background/Objectives</b>: Takayasu's arteritis (TAK) is an inflammatory vascular disease, but atherosclerotic mechanisms may also contribute to vascular injury in TAK. This study aimed to evaluate the clinical and imaging characteristics of TAK patients with and without iliofemoral artery involvement on FDG-PET/CT, focusing on the association with classical atherosclerotic risk factors. <b>Methods</b>: Patients fulfilling the 1990 ACR classification criteria for TAK who underwent FDG-PET/CT imaging during follow-up were retrospectively analyzed. Demographic, clinical, and laboratory data were recorded, including traditional cardiovascular risk factors: diabetes, hypertension, hyperlipidemia, smoking, obesity (BMI ≥ 30 kg/m²), and family history of cardiovascular disease. PET vascular activity score (PETVAS) and visual analysis were used to assess vascular inflammation. <b>Results</b>: PET/CT scans of 77 TAK patients (F/M = 63/14) were evaluated. The mean age was 43.0 ± 12.9 years, and the mean disease duration was 120.1 ± 88.8 months. Iliofemoral artery involvement was observed in nine (12%) patients. Compared to those without such involvement, these patients were older (52.5 ± 17.4 vs. 41.3 ± 12.1 years, <i>p</i> = 0.098), more frequently male (44% vs. 6%, <i>p</i> = 0.015), and had higher CRP levels (38.5 mg/L vs. 10.7 mg/L, <i>p</i> = 0.026). Smoking (77% vs. 40%, <i>p</i> = 0.045) and chronic kidney disease (22% vs. 4%, <i>p</i> = 0.046) were also more prevalent. PET activity according to visual analysis was higher among those with iliofemoral involvement (67% vs. 27%, <i>p</i> = 0.015). In multivariate analysis, older age (OR = 1.07, <i>p</i> = 0.044) and male sex (OR = 6.68, <i>p</i> = 0.039) were independently associated with iliofemoral artery involvement. <b>Conclusions</b>: Iliofemoral artery involvement on PET/CT in TAK patients was associated with traditional atherosclerotic risk factors-particularly older age, male sex and smoking. These findings suggest that atherosclerotic mechanisms may coexist with or amplify vascular inflammation in TAK. Aggressive management of cardiovascular risk factors should therefore be emphasized in this subgroup of TAK patients.