Measurement of Ga-DOTATOC Uptake in the Thoracic Aorta and Its Correlation with Cardiovascular Risk.

PURPOSE

Ga-labeled 1,4,7,10-tetraazacyclododecane-,',″,‴-tetraacetic acid-d-Phe-Tyr-octreotide (Ga-DOTATOC) is taken up by activated macrophages, which accumulate in active inflammatory lesions. The purpose of this study was to investigate the feasibility of Ga-DOTATOC PET/CT for assessment of vulnerable plaque, by evaluating correlation between aortic uptake of Ga-DOTATOC and cardiovascular risk factors.

METHODS

Fifty patients with neuroendocrine tumors who underwent Ga-DOTATOC PET/CT were retrospectively enrolled. The uptakes in the thoracic aorta were measured by two methods: multi-sample region-of-interest (ROI) method and single volume-of-interest (VOI) method. TBR, TBR, TBR, and TBR were defined by maximum and mean target-to-background ratio (TBR) from the multi-sample ROI method and the single VOI method, respectively.

RESULTS

Framingham risk score (FRS) exhibited significant correlations with TBR and TBR, as well as TBR ( = 0.3389-0.4593,  < 0.05 for all). TBR and TBR were significantly higher in high FRS group than in low FRS group (1.48 ± 0.21 vs. 1.70 ± 0.17,  < 0.001 for TBR and 1.90 ± 0.33 vs. 2.25 ± 0.36,  = 0.002 for TBR). TBR exhibited high correlations between the two measuring methods ( = 0.9684,  < 0.001 for TBR and TBR and  = 0.8681,  < 0.001 for TBR and TBR).

CONCLUSIONS

Ga-DOTATOC uptake in the thoracic aorta exhibited a significant correlation with cardiovascular risk factors, which suggests the feasibility of Ga-DOTATOC PET for vulnerable plaque imaging, with a simple measurement of the single VOI method that is comparable to the multi-sample ROI-based approach.