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DOI: 10.1055/s-0039-1683537
Role of somatostatin receptor and FDG imaging in capturing plaque inflammation: a PET/CT analysis, corroborated by clinical data
Publication History
Publication Date:
27 March 2019 (online)
Ziel/Aim:
Evidence indicates that atherosclerosis-related vascular inflammation can be measured with 18F-FDG-PET. However, background uptake, patients' comorbidities, and concomitant treatments may hamper signal semi-quantification. Up-regulation of somatostatin receptor subtype-2 occurs on activated macrophages and it has been suggested that somatostatin-receptor PET imaging may also capture vascular inflammation. This study aimed to compare the vascular distribution and biological determinants of plaque inflammation, as assessed by both 68Ga-DOTATOC and 18F-FDG-PET.
Methodik/Methods:
27 patients (12 males, mean age 69.4 ± 8, range 56 – 87) underwent an 18F-FDG and a 68 Ga-DOTATOC-PET within a four-week period for clinical reasons. Cardiovascular-risk was stratified using a simplified version of the Framingham model. VOIs were drawn on the entire aorta in both the 18F-FDG and the 68-Ga DOTATOC PET/CT. In these VOIs, SUVmean and SUVmax were normalized to blood activity to obtain the aortic target-to-background ratio (TBRmean and TBRmax). Differences in mean values and linear regression analysis were tested for these values and cardiovascular risk factors.
Ergebnisse/Results:
Aortic TBRmax was significantly higher on 68Ga-DOTATOC than on 18F-FDG-PET images (5.7 ± 2.2 Vs. 2 ± 1.2, p < 0.01) while no differences were highlighted for TBRmean. Cardiovascular risk score correlated with both TBRmean (R = 0.82 and 0.81 for 18F-FDG-PET and for 68Ga-DOTATOC, respectively, p < 0.001). Finally, only TBRmax of 68Ga-DOTATOC (and not of 18F-FDG) was higher in diabetics (n = 12) with respect to the remaining patients (6 ± 0.8 Vs. 4.9 ± 0.6, p < 0.05).
Schlussfolgerungen/Conclusions:
Correlations of both tracers uptake upon ongoing biological determinants of vascular inflammation confirm that PET might provide a window on plaque pathophysiology. In this framework, 68Ga-DOTATOC vascular signal demonstrated to better capture the presence of arterial hot spots and was able to better highlight plaque inflammation in diabetic patients.
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