Multimodality imaging of atherosclerotic plaque activity and composition using FDG-PET/CT and MRI in carotid and femoral arteries.
OBJECTIVE
To evaluate the relationship between atherosclerotic plaque inflammation, as assessed by FDG-positron emission tomography/computed tomography (FDG-PET/CT), and plaque morphology and composition, as assessed by magnetic resonance imaging (MRI), in the carotid and femoral arteries.


METHODS
Sixteen patients underwent FDG-PET/CT and MRI (T2-weighted (T2W) and proton density weighted (PDW)) of the carotid and femoral arteries. For every image slice, two observers determined the corresponding regions of the FDG-PET/CT and MRI image sets by matching CT and T2W axial images. Each plaque was then classified into one of three groups according to the CT appearance and T2W/PDW signal: (1) collagen, (2) lipid-necrotic core and (3) calcium. Arterial FDG uptake was measured for each plaque and normalized to vein FDG activity to produce a blood-normalized artery activity called the target to background ratio (TBR). The vessel wall thickness (VWT), the vessel wall area and the total vessel wall area were measured from the T2W MR images.


RESULTS
The TBR value was higher in the lipid-necrotic core group compared to the collagen and calcium groups, (p<0.001). The lipid-necrotic core group demonstrated a significant TBR variation according to the median of the VWT (TBR=1.26+/-0.25 vs. 1.50+/-0.12). There was no correlation with other morphological MR parameters.


CONCLUSIONS
This study demonstrates the complementary value of non-invasive FDG-PET/CT and MR imaging for the evaluation of atherosclerotic plaque composition and activity. Lipid-rich plaques are more inflamed than either calcified or collagen-rich plaques.
Silvera
Stephane S
SS
Sinai Translational and Molecular Imaging Institute and Imaging Science Laboratories, Mount Sinai School of Medicine, One Gustave L Levy Place, New York, NY 10029, USA.
Aidi
Hamza El
HE
Rudd
James H F
JH
Mani
Venkatesh
V
Yang
Lingde
L
Farkouh
Michael
M
Fuster
Valentin
V
Fayad
Zahi A
ZA
D000368:Aged; D050197:Atherosclerosis / Q000175:diagnosis* / Q000378:metabolism; D002118:Calcium / Q000032:analysis; D002340:Carotid Artery Diseases / Q000175:diagnosis* / Q000378:metabolism; D003094:Collagen / Q000032:analysis; D005260:Female; D005263:Femoral Artery / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007249:Inflammation / Q000175:diagnosis* / Q000378:metabolism; D008055:Lipids / Q000032:analysis; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
D008055:Lipids; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D003094:Collagen; D002118:Calcium