Adrenal glands uptake patterns in ¹⁸F-Fluoroethylcholine PET/CT

To find reasons of different radioactive choline adrenal uptake in prostate or renal cancer patients who underwent 18F-fluoroethylcholine positron emission tomography/computed tomography.

Forty-nine positron emission tomography/computed tomography studies with radioactive choline (96 adrenal glands) were analysed with respect to the adrenal glands shape, uptake pattern and maximum standardised uptake value. Fifteen other parameters were recorded, assessed or counted, ratios of chosen parameters were calculated, and checked for correlation with adrenal glands uptake.

Adrenal glands presented a wide range of radioactive choline uptake intensities (range 2-7.9) and different uptake patterns (diffuse, focal or mixed). Maximum uptake in the right (4.3±1.2) adrenal gland positively correlated with the thickness of the parenchyma at the point of maximal uptake (5.3mm±1.5) (p=0.000). Maximum uptake in the right and left adrenal gland, as well as mean adrenal gland uptake, correlated with maximum uptake in the pituitary gland (p=0.000, p=0.000 and p=0.001, respectively) and with maximum uptake in liver (p=0.008, p=0.000 and p=0.011, respectively). Neither hormonal treatment nor patients' age significantly correlated with standardised uptake values of adrenal glands in the studied group.

The variability of radiocholine uptake in adrenal glands depends probably on overall body metabolism and hypophyseal function expressed by statistically significant correlation with liver and pituitary gland uptake. Predominant focal or mixed with focal areas uptake patterns on positron emission tomography in normal in computed tomography adrenal glands should be assessed with caution to avoid a diagnostic mistake.