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18F-FDG uptake in the normal appendix in adults: PET/CT evaluation

  • Christopher SilmanEmail author
  • Shunro Matsumoto
  • Asami Ono
  • Maki Kiyonaga
  • Kenichiro Otsuka
Original Article

Abstract

Objective

This study aimed to determine the level of 18F fluorodeoxyglucose (18F-FDG) activity in the normal adult appendix using positron emission tomography/computed tomography (PET/CT).

Materials and methods

We performed a retrospective review of PET/CT images using 18F-FDG in 563 consecutive asymptomatic adult patients without appendiceal pathology. We excluded 257 patients for an undetected or obscured appendix and three patients for appendicitis found on CT imaging. FDG uptake in the appendix was qualitatively and quantitatively assessed. The maximum standardized uptake value (SUVmax) was calculated for quantitative analysis with SUVmax of the normal liver for comparison. A total of 303 patients (200 males, 103 females, mean age of 66 years) were included in this study. Medical charts and histories were evaluated for patients who showed positive FDG accumulation. Pearson’s correlations between appendiceal SUVmax and age, body mass index, and blood glucose levels were analyzed.

Results

The mean appendiceal SUVmax was 1.14 (range 0.52–5.12) with an appendix-to-liver SUVmax ratio of 0.34 (range 0.06–1.28). Three patients qualitatively showed a positive FDG accumulation with appendiceal SUVmax greater than 3.00. There were no correlations between appendiceal SUVmax and age, body mass index, or blood glucose levels.

Conclusions

FDG in the normal adult appendix shows a low activity level and is lower compared with normal liver. However, the normal appendix can rarely show high FDG accumulation. In such cases, differentiation from appendiceal pathology solely by PET/CT images would be difficult.

Keywords

Appendix Adult PET/CT Normal variants 

Notes

Acknowledgements

The authors would like to express special thanks to Mr Naoto Kunitake, medical student in our university, and we also thank Ellen Knapp, PhD, and Gillian Campbell, PhD, from Edanz Group (http://www.edanzediting.com/ac), for editing the draft of the manuscript. The authors declare they have no conflict of interest.

Funding

No funding was received for this work.

Compliance with ethical standards

Ethical considerations

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation and with the Helsinki Declaration of 1975 (revised in 2008). This retrospective study was approved by our institutional review boards.

References

  1. 1.
    Toriihara A, Yoshida K, Umehara I, Shibuya H. Normal variants of bowel FDG uptake in dual-time-point PET/CT imaging. Ann Nucl Med. 2011;25(3):173–8.CrossRefGoogle Scholar
  2. 2.
    Reavey HE, Adina L, Alazraki, Simoneaux SF. Normal patterns of 18F-FDG appendiceal uptake in children. Pediatr Radiol. 2014;44:398–402.CrossRefGoogle Scholar
  3. 3.
    Purandare NC, Gandhi A, Puranik AD, Agrawal A, Shah S, Patil A, et al. Use of FDG/PET CT to diagnose malignancy as the cause of mucocele of the appendix. Indian J Gastroenterol. 2014;33(1):79–81.CrossRefGoogle Scholar
  4. 4.
    Ogawa S, Itabashi M, Kameoka S. Significance of FD-PET in identification of diseases of the appendix- based on experience of two cases falsely positive for FDG accumulation. Case Rep Gastroenterol. 2009;3(1):125–30.CrossRefGoogle Scholar
  5. 5.
    Koff SG, Sterbis JR, Davison JM, Montilla-Soler JL. A unique presentation of appendicitis: F-18 FDG PET/CT. Clin Nucl Med. 2006;31(11):704–6.CrossRefGoogle Scholar
  6. 6.
    Sprinz C. Effects of blood glucose level on 18F-FDG uptake for PET/CT in normal organs: a systematic review. PLoS One. 2018;13(2):e0193140.CrossRefGoogle Scholar
  7. 7.
    Mahmud MH, Nordin AJ, Saad FFA, Azman AZ. Impacts of biological and procedural factors on semiquantification uptake value of liver in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography imaging. Quant Imaging Med Surg. 2015;5(5):700–7.Google Scholar
  8. 8.
    Kersah S, Partovi S, Traughber BJ, Muzic RF, Schluchter MD, O’Donnel JK, et al. Comparison of standardized uptake values in normal structures between PET/CT and PET/MRI in an oncology patient population. Mol Imaging Biol. 2013;15(6):776–85.CrossRefGoogle Scholar
  9. 9.
    Cook GJ, Maisey MN, Fogelman I. Normal variants, artefacts and interpretative pitfalls in PET imaging with 18-fluoro-2-deoxyglucose and carbon-11 methionine. Eur J Nucl Med. 1999;26(10):1363–78.CrossRefGoogle Scholar
  10. 10.
    Sarji AS. Physiological uptake in FDG PET simulating disease. Biomed Imaging Interv J. 2006;2(4):59.Google Scholar
  11. 11.
    Sprinz C, Altmayer S, Zanon M, Watte G, Irion K, Marchiori E, et al. Effect of blood glucose level on 18F-FDG uptake for PET/CT in normal organs: a systematic review. PloS One 13(2): e0193140.Google Scholar
  12. 12.
    Sprinz C, Zanon M, Altmayer S, Watte G, Irion K, Marchiori E, et al. Effects of blood glucose level on 18F fluorodeoxyglucose (18F-FDG) uptake for PET/CT in normal organs: an analysis on 5623 patients. Sci Rep. 2018;8:21–6.CrossRefGoogle Scholar
  13. 13.
    Curtin KR, Fitzgerald SW, Nemcek AA, Hoff FL, Vogelzang RL. CT Diagnosis of acute appendicitis: imaging findings. AJR. 1995;164:905–9.CrossRefGoogle Scholar
  14. 14.
    Athanasios N, Chalazonitis, Tzovara I, Sammouti E, Ptohis N, Sotiropoulou E, et al. CT in appendicitis. Diagn Interv Radiol. 2008;13:19–25.Google Scholar
  15. 15.
    Nakamoto Y, Tatsumi M, Hammoud D, Cohade C, Osman MM, Wahl RL. Normal FDG distribution patterns in the head and neck: PET/CT evaluation. Radiology. 2005;234:879–85.CrossRefGoogle Scholar
  16. 16.
    Ganz ML, Wintfeld N, Li Q, Alas V, Langer J, Hammer M. The association of body mass index with the risk of type 2 diabetes: a case-control study nested in an electronic health records system in the United States. Diabetol Metab Synd. 2014;6:50.CrossRefGoogle Scholar
  17. 17.
    Razi M, Bashir H, Hassan A, Niazi IK. False positive finding of F18-FDG in non-Hodgkin’s lymphoma; an inflamed appendix. J Pak Med Assoc. 2018;68(6):971.Google Scholar
  18. 18.
    Kaim AH, Weber B, Kurrer MO, Westera G, Schweitzer A, Gottschalk J, et al. 18F-FDG and 18F-FET uptake in experimental soft tissue infection. Eur J Nucl Med. 2002;29:648–54.CrossRefGoogle Scholar
  19. 19.
    Lin CY, Ding HJ, Lin CC, Chen CC, Sun SS, Kao CH. Impact of age on FDG uptake in the liver on PET scan. Clin Imaging. 2010;34:348–50.CrossRefGoogle Scholar
  20. 20.
    Büsing KA, Schönberg SO, Brade J, Wasser K. Impact of blood glucose, diabetes, insulin, and obesity on standardized uptake values in tumors and healthy organs on 18F-FDG PET/CT. Nucl Med Biol. 2013;40:206–13.CrossRefGoogle Scholar

Copyright information

© The Japanese Society of Nuclear Medicine 2019

Authors and Affiliations

  1. 1.Department of RadiologyOita University Faculty of MedicineYufu CityJapan

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