Atherosclerosis inflammation imaging with 18F-FDG PET: carotid, iliac, and femoral uptake reproducibility, quantification methods, and recommendations.
Atherosclerosis imaging with 18F-FDG PET is useful for tracking inflammation within plaque and monitoring the response to drug therapy. Short-term reproducibility of this technique in peripheral artery disease has not been assessed, and the optimal method of 18F-FDG quantification is still debated. We imaged 20 patients with vascular disease using 18F-FDG PET twice, 14 d apart, and used these data to assess reproducibility measures and compare 2 methods of 18F-FDG uptake measurement. We also reviewed the literature on quantification methods to determine the optimal measures of arterial 18F-FDG uptake for future studies.


METHODS
Twenty patients with vascular disease underwent PET/CT of the iliac, femoral, and carotid arteries 90 min after 18F-FDG administration. In 19 patients, repeat testing was performed at 2 wk. Coregistration and attenuation correction were performed with CT. Vessel 18F-FDG uptake was measured as both the mean and maximum blood-normalized standardized uptake value (SUV), known as the target-to-background ratio (TBR). We assessed interscan, interobserver, and intraobserver agreement.


RESULTS
Nineteen patients completed both imaging sessions. The carotid and peripheral arteries all have excellent short-term reproducibility of the 18F-FDG signal, with intraclass correlation coefficients all greater than 0.8 for all measures of reproducibility. Both mean and maximum TBR measurements for quantifying 18F-FDG uptake are equally reproducible. 18F-FDG uptake was significantly higher in the carotid arteries than in both iliac and femoral vessels (P < 0.001 for both).


CONCLUSIONS
We found that both mean and maximum TBR in the carotid, iliac, and femoral arteries were highly reproducible. We suggest the mean TBR be used for tracking systemic arterial therapies, whereas the maximum TBR is optimal for detecting and monitoring local, plaque-based therapy.
Rudd
James H F
JH
Imaging Science Laboratories, Mount Sinai School of Medicine, New York, New York, USA. jhfr2@cam.ac.uk
Myers
Kelly S
KS
Bansilal
Sameer
S
Machac
Josef
J
Pinto
Cathy Anne
CA
Tong
Christopher
C
Rafique
Ash
A
Hargeaves
Richard
R
Farkouh
Michael
M
Fuster
Valentin
V
Fayad
Zahi A
ZA
D001167:Arteritis / Q000000981:diagnostic imaging* / Q000378:metabolism; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000378:metabolism; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging* / Q000378:metabolism; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging* / Q000378:metabolism; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18