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Open Access Preliminary research

68Ga-DOTATATE PET/CT for the detection of inflammation of large arteries: correlation with18F-FDG, calcium burden and risk factors

Xiang Li12, Samuel Samnick13*, Constantin Lapa1, Ina Israel1, Andreas K Buck13, Michael C Kreissl13 and Wolfgang Bauer23

Author Affiliations

1 Department of Nuclear Medicine, University of Wuerzburg, Oberdürrbacher Str. 6, Wuerzburg, D-97080, Germany

2 Department of Internal Medicine I, University of Wuerzburg, Wuerzburg, D-97080, Germany

3 Comprehensive Heart Failure Centre, University Hospital Wuerzburg, Wuerzburg, D-97080, Germany

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EJNMMI Research 2012, 2:52  doi:10.1186/2191-219X-2-52

Published: 27 September 2012

Abstract

Background

Ga-[1,4,7,10-tetraazacyclododecane-N,N′,N″,N′″-tetraacetic acid]-d-Phe1,Tyr3-octreotate (DOTATATE) positron emission tomography (PET) is commonly used for the visualization of somatostatin receptor (SSTR)-positive neuroendocrine tumors. SSTR is also known to be expressed on macrophages, which play a major role in inflammatory processes in the walls of coronary arteries and large vessels. Therefore, imaging SSTR expression has the potential to visualize vulnerable plaques. We assessed 68Ga-DOTATATE accumulation in large vessels in comparison to 18F-2-fluorodeoxyglucose (FDG) uptake, calcified plaques (CPs), and cardiovascular risk factors.

Methods

Sixteen consecutive patients with neuroendocrine tumors or thyroid cancer underwent both 68Ga-DOTATATE and 18F-FDG PET/CT for staging or restaging purposes. Detailed clinical data, including common cardiovascular risk factors, were recorded. For a separate assessment, they were divided into a high-risk and a low-risk group. In each patient, we calculated the maximum target-to-background ratio (TBR) of eight arterial segments. The correlation of the TBRmean of both tracers with risk factors including plaque burden was assessed.

Results

The mean TBR of 68Ga-DOTATATE in all large arteries correlated significantly with the presence of CPs (r = 0.52; p < 0.05), hypertension (r = 0.60; p < 0.05), age (r = 0.56; p < 0.05), and uptake of 18F-FDG (r = 0.64; p < 0.01). There was one significant correlation between 18F-FDG uptake and hypertension (0.58; p < 0.05). Out of the 37 sites with the highest focal 68Ga-DOTATATE uptake, 16 (43.2%) also had focal 18F-FDG uptake. Of 39 sites with the highest 18F-FDG uptake, only 11 (28.2%) had a colocalized 68Ga-DOTATATE accumulation.

Conclusions

In this series of cancer patients, we found a stronger association of increased 68Ga-DOTATATE uptake with known risk factors of cardiovascular disease as compared to 18F-FDG, suggesting a potential role for plaque imaging in large arteries. Strikingly, we found that focal uptake of 68Ga-DOTATATE and 18F-FDG does not colocalize in a significant number of lesions.

Keywords:
Atherosclerotic plaque; 68Ga-DOTATATE; Somatostatin receptor; Cardiovascular risk factors; Macrophage