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DOI: 10.1055/s-0043-1769942
Physiological 18F-FDG Uptake in Normal Pituitary Gland on Digital PET Scanner
dranjalinm@gmail.com
Introduction: Majority of PET/CT scanners around world are analog (cPET) scanners. Pituitary gland (PG) is usually not visualized on 18F-FDG PET scans, and its detection requires further evaluation.1,2 Recently developed digital scanners (dPET) have higher sensitivity, resolution, and image contrast, which leads to increased uptake of PG.3–6 Adequate knowledge of pituitary uptake will lead to correct interpretation of results and reduce additional imaging, saving radiation, cost, and time.
Methods: This retrospective study conducted at Sultan Qaboos Comprehensive Cancer Care and Research Centre. Muscat, between August 1, 2021, to April 30, 2022. All 18F-FDG PET CT scans done on dPET with MRI brain within 6 months were included. Suboptimal quality images with unavailability of pituitary fossa in the image and scans with PG pathology were excluded. Additionally, 20 controls done on cPET were included. All images were acquired with similar and standard protocol. PG uptake was assessed visually and quantitatively.
Focal uptake in PG was considered as positive and absence of uptake as negative. Using a 3-point color bar, the uptake was graded as mild, moderate, and severe. Quantitative assessment was made by measuring standardized uptake values (SUVs) for the pituitary, background, and mediastinum. For statistical analysis, nonparametric Mann–Whitney U test was applied to compare between digital and analog PET.
Results: In the study population of 88 patients, the mean age was 54.4 years, 25 males/63 females, while in controls the mean age was 58.1 years with 5 men and 15 women. Among the 88 patients, PG uptake was seen in 43 (48.8%). In the 43 patients, 31 (72%) showed mild uptake, 11 (26%) moderate, and 1 (2%) showed moderate to severe uptake. None of them showed severe uptake. In the control group, 3 (15%) showed mild uptake with no moderate or severe uptake.
Patients on dPET showed higher pituitary SUVmax and mean compared with cPET with p-value less than 0.05. The pituitary/background SUVmax is higher in dPET with no difference in mean compared with cPET.
Conclusion: Physiological pituitary uptake is common on dPET and mild to moderate uptake does not require further evaluation. A severe uptake should be evaluated further to exclude pituitary pathology.
Publikationsverlauf
Artikel online veröffentlicht:
25. Mai 2023
© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)
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