Complementarity between¹⁸F-FDG PET/CT and Ultrasonography or Angiography in Carotid Plaque Characterization

Abstract

F-fluorodeoxyglucose (FDG) positron emission tomography (PET) versus angiography and ultrasonography in carotid plaque characterization.MethodszzWe characterized two groups of patients with recently (<1 month) symptomatic (n=14; age=71.8±8.6 years, mean±SD) or chronic (n=13, age=68.9±9.0 years) carotid stenosis using a battery of imaging tests: diffusion magnetic resonance (MR) imaging, MR or transfemoral angiography, duplex ultrasonography (DUS), and carotid FDG-PET/computed tomography.ResultszzThe degree of angiographic stenosis was greater in patients with recently symptomatic carotid plaques (67.5±21.5%) than in patients with chronic carotid plaques (32.4±26.8%, p=0.001). Despite the significant difference in the degree of stenosis, lesional maximum standardized uptake values (maxSUVs) on the carotid FDG-PET did not differ between the recently symptomatic (1.56±0.53) and chronic (1.56±0.34, p=0.65) stenosis groups. However, lesional-tocontralesional maxSUV ratios were higher in the recently symptomatic stenosis group (113±17%) than in the chronic stenosis group (98±10%, p=0.017). The grayscale median value of the lesional DUS echodensities was lower in the recently symptomatic stenosis group (28.2±10.0, n=9) than in the chronic stenosis group (53.9±14.0, n=8; p=0.001). Overall, there were no significant correlations between angiographic stenosis, DUS echodensity, and FDG-PET maxSUV. Case/subgroup analyses suggested complementarity between imaging modalities.ConclusionszzThere were both correspondences and discrepancies between the carotid FDG-PET images and DUS or angiography data. Further studies are required to determine whether FDG-PET could improve the clinical management of carotid stenosis.

Molecular imaging of carotid artery atherosclerosis with PET: a systematic review

“…In patients with atherosclerosis, smoking [12,21,40,44], previous anti-coagulant or statin therapy [12,21,40,44], impaired lipid profile [12,21,44], male gender [21,44], hypertension [12,21,44], old age [21,44], diabetes [12,44], history of cardiovascular diseases [21], high body mass index [21], and metabolic syndrome [40] appeared not to be associated with a higher FDG uptake. In contrast, some studies showed significant correlation between FDG uptake and male gender [40,42], age [42], lipid profile [40], and history of cerebrovascular disease [42] in atherosclerotic patients.…”

“…FDG uptake was higher in carotid artery specimens of patients with more severe disease (stroke vs. transient ischemic attack; maximum standardized uptake value (SUVmax), i.e. FDG uptake corrected by the background mean uptake by micro-PET, 5.3 vs 3.7, p<0.05) [13] or with an 'acute' cerebrovascular event (<90 days vs. >90 days: SUVmax 3.1 vs. 2.5, p=0.01) [12]. Kim et al showed in a recent study that patients with high carotid FDG uptake are more prone to early recurrence of ischemic stroke [19], although a prior study by Arauz et al was unable to demonstrate this prognostic trend [20].…”

“…Kim et al showed in a recent study that patients with high carotid FDG uptake are more prone to early recurrence of ischemic stroke [19], although a prior study by Arauz et al was unable to demonstrate this prognostic trend [20]. In patients with symptomatic atherosclerosis, ipsilateral carotid FDG uptake correlated with the contralateral carotid FDG uptake [21,22], and such that the ipsilateral was higher than contralateral FDG uptake [12,[22][23][24][25]. In contrast, studies performed early after a cerebrovascular event (less than 10 days) showed no difference between ipsilateral and contralateral FDG uptake [26,27].…”

“…Carotid FDG uptake in patients with atherosclerosis was mostly compared to that of subjects without atherosclerosis. Uptake of FDG [11][12][13][14][15][16][17] was more pronounced in atherosclerotic patients with than without symptoms except that in one study this difference was not present [18]. FDG uptake was higher in carotid artery specimens of patients with more severe disease (stroke vs. transient ischemic attack; maximum standardized uptake value (SUVmax), i.e.…”

“…Based on the immunohistochemical studies, FDG uptake correlated with CD68 [12,23,24,44,49,[52][53][54][55][56], Cathepsin K [53,54,56], CD45 [12], MMP-9 [52], IL-18 [53], GLUT-1 [56], and VEGF expression [24]. However, some studies reported that FDG does not correlate with CD68 [26], MMP-9 [54] and VEGF [54].…”