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

Li X, Samnick S, Lapa C, Israel I, Buck AK, Kreissl MC, Bauer W - EJNMMI Res (2012)

Bottom Line: There was one significant correlation between 18F-FDG uptake and hypertension (0.58; p < 0.05).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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear Medicine, University of Wuerzburg, Oberdürrbacher Str, 6, Wuerzburg, D-97080, Germany. Samnick_S@klinik.uni--wuerzburg.de.

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.

No MeSH data available.


Related in: MedlinePlus

Colocalization of focal 68Ga-DOTATATE and 18F-FDG uptake. Comparison of 37 foci of increased 68Ga-DOTATATE uptake (left) and 39 foci of increased 18F-FDG uptake (right) with respect to colocalized focal uptake of the other radiotracer and calcification. Imaging findings were characterized as concordant when there was agreement in positive detection with both tracers, and as discordant in cases of discrepancy between the two tracers' uptake.
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Figure 4: Colocalization of focal 68Ga-DOTATATE and 18F-FDG uptake. Comparison of 37 foci of increased 68Ga-DOTATATE uptake (left) and 39 foci of increased 18F-FDG uptake (right) with respect to colocalized focal uptake of the other radiotracer and calcification. Imaging findings were characterized as concordant when there was agreement in positive detection with both tracers, and as discordant in cases of discrepancy between the two tracers' uptake.

Mentions: When assessing the PET/CT image data, we found colocalized uptake of both tracers (Figure 1) as well as foci of increased uptake of only one of the tracers (Figures 2 and3). On evaluation of the 37 sites with the highest 68Ga-DOTATATE TBR value, a colocalized focal increase of 18F-FDG uptake was observed in 43.2% (16 sites, 10 sites with calcification, and 6 sites without calcification), while 56.8% of the sites (21 sites, 6 sites with calcification, and 15 sites without calcification) were negative. Of 39 sites with the highest 18F-FDG uptake, only 28.2% had an increased uptake of 68Ga-DOTATATE (11 sites, 4 sites with calcification, and 7 sites without calcification), while 71.8% of the sites (28 sites, 6 sites with calcification, and 22 sites without calcification) were recorded as negative (Figure 4). In total, 12 patients were examined to have focal increased uptakes of 68Ga-DOTATATE, while 10 patients were found to have 18F-FDG focal increased uptakes. As previously recommended, we also used the mean TBR, which was calculated as the mean value of TBRs from eight arterial segments, for statistical analyses.


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

Li X, Samnick S, Lapa C, Israel I, Buck AK, Kreissl MC, Bauer W - EJNMMI Res (2012)

Colocalization of focal 68Ga-DOTATATE and 18F-FDG uptake. Comparison of 37 foci of increased 68Ga-DOTATATE uptake (left) and 39 foci of increased 18F-FDG uptake (right) with respect to colocalized focal uptake of the other radiotracer and calcification. Imaging findings were characterized as concordant when there was agreement in positive detection with both tracers, and as discordant in cases of discrepancy between the two tracers' uptake.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475087&req=5

Figure 4: Colocalization of focal 68Ga-DOTATATE and 18F-FDG uptake. Comparison of 37 foci of increased 68Ga-DOTATATE uptake (left) and 39 foci of increased 18F-FDG uptake (right) with respect to colocalized focal uptake of the other radiotracer and calcification. Imaging findings were characterized as concordant when there was agreement in positive detection with both tracers, and as discordant in cases of discrepancy between the two tracers' uptake.
Mentions: When assessing the PET/CT image data, we found colocalized uptake of both tracers (Figure 1) as well as foci of increased uptake of only one of the tracers (Figures 2 and3). On evaluation of the 37 sites with the highest 68Ga-DOTATATE TBR value, a colocalized focal increase of 18F-FDG uptake was observed in 43.2% (16 sites, 10 sites with calcification, and 6 sites without calcification), while 56.8% of the sites (21 sites, 6 sites with calcification, and 15 sites without calcification) were negative. Of 39 sites with the highest 18F-FDG uptake, only 28.2% had an increased uptake of 68Ga-DOTATATE (11 sites, 4 sites with calcification, and 7 sites without calcification), while 71.8% of the sites (28 sites, 6 sites with calcification, and 22 sites without calcification) were recorded as negative (Figure 4). In total, 12 patients were examined to have focal increased uptakes of 68Ga-DOTATATE, while 10 patients were found to have 18F-FDG focal increased uptakes. As previously recommended, we also used the mean TBR, which was calculated as the mean value of TBRs from eight arterial segments, for statistical analyses.

Bottom Line: There was one significant correlation between 18F-FDG uptake and hypertension (0.58; p < 0.05).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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear Medicine, University of Wuerzburg, Oberdürrbacher Str, 6, Wuerzburg, D-97080, Germany. Samnick_S@klinik.uni--wuerzburg.de.

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.

No MeSH data available.


Related in: MedlinePlus