Purpose: This study aimed to compare the clinical significance of two parameters, division of standardized uptake value (SUV) of target arterial activity by background venous blood pool activity ( ­SUVA/V ) and subtraction of background venous blood pool activity from SUV of target arterial activity ­(SUVA‑V ) of carotid arteries with atherosclerotic plaques using 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT). Methods: Patients aged 50 years or more who were diagnosed with carotid artery stenosis of 50% or more with carotid Doppler ultrasonography and had torso 18F-FDG PET/CT were enrolled retrospectively and classified patients who developed cerebrovascular events (CVEs) within 5 years after 18F-FDG PET/CT scan as the active group and patients who did not experience the CVE within 5 years as an inactive group. We calculated SUVA/V and ­SUVA‑V using measurements of ­SUVmax Results: SUVA‑V ­ SUVA‑V_high , and ­SUVA‑V_low were significantly higher in the active group than in the inactive group, but neithe SUVA/V ­ SUVA‑V_high , nor ­­SUVA‑V_low showed significant differences between the active and inactive groups. Thedifference in rank between groups of SUVA‑V_high and ­SUVA‑V_low was greater than the difference in rank between groups of SUVA‑V_high and ­­SUVA‑V_low . The CVE incidence differed between SUVA‑V_high and ­­SUVA‑V_low of high carotid FDG uptake, but the CVE incidence did not differ between SUVA‑V_high and ­­SUVA‑V_low of high carotid FDG uptake. Conclusion SUVA‑V may be a more rational solution than ­SUVA/V for evaluating atherosclerotic plaque inflammation on 18F-FDG PET/CT.