Association of vascular 18F-FDG uptake with vascular calcification.
Both calcification and FDG uptake have been advocated as indicators of atheroma. Atheromas calcify as cells in the lesion undergo apoptosis and necrosis during evolution of the lesion and at the end stage of the lesion. FDG concentrates in lesions due to the relatively dense cellularity in regions of inflammation of active atheromas. This investigation examines the geographic relationship of focal vascular (18)F-FDG uptake, as a marker of atherosclerotic inflammation, to arterial calcification detected by contemporaneous CT.


METHODS
We reviewed PET/CT images from 78 patients who were referred for tumor staging for the presence of vascular (18)F-FDG uptake and vascular calcification. Arterial wall (18)F-FDG accumulation greater than adjacent blood-pool activity was considered inflammation. Arterial attenuation of >130 Hounsfield units was considered calcification. Sites in the ascending and descending aorta, the carotid and iliac arteries, and the coronary territories were examined on the emission, CT, and fusion images on a point-by-point basis. When lesions were seen, we evaluated whether they were overlapping or discrete.


RESULTS
The (18)F-FDG arterial distribution was consistent with established atherosclerotic topography, with increased uptake in the thoracic aorta, at the carotid bifurcation, and in the proximal coronary vessels. Arteries typically displayed a patchwork of normal vessel, focal inflammation, or calcification; inflammation and calcification overlapped in <2% of cases. Arterial inflammation preceded calcification, in terms of mean patient age. Coronary inflammation was more prevalent in patients with more cardiovascular risk factors.


CONCLUSIONS
Vascular calcification and vascular metabolic activity rarely overlap, suggesting these findings represent different stages in the evolution of atheroma.
Dunphy
Mark P S
MP
Nuclear Medicine Service, Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. dunphym@mskcc.org
Freiman
Alvin
A
Larson
Steven M
SM
Strauss
H William
HW
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001161:Arteriosclerosis / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002648:Child; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014652:Vascular Diseases / Q000000981:diagnostic imaging / Q000378:metabolism
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18