A 65-year-old man with an occluded popliteal artery aneurysm and calf claudication underwent PET/CT imaging with F-NaF to assess the status of active microcalcification in the aneurysm site and additional lower extremity arteries. CT imaging revealed macrocalcification of the aneurysm that colocalized with elevated retention of F-NaF on PET images. PET/CT detected additional distal arterial sites with focal uptake of F-NaF that did not coincide with CT-detectable macrocalcification. This report highlights a case of active microcalcification in an occlusive peripheral aneurysm using PET/CT. PET/CT may provide molecular insight into the remodeling of lower extremity aneurysms and atherosclerotic lesions.