Published Online:

Normal distribution of FDG uptake, physiologic variants in distribution, benign lesions that may be misinterpreted as malignancies, and PET/CT artifacts are discussed and illustrated with respect to pediatric oncology patients.

Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) is increasingly being used in the evaluation of pediatric oncology patients. However, the normal distribution of 18F FDG uptake in children is unique and may differ from that in adults. A number of physiologic variants are commonly encountered, including normal physiologic uptake in the head and neck, heart, breast, thymus, liver, spleen, gastrointestinal tract, genital system, urinary collecting system, bone marrow, muscles, and brown adipose tissue. Benign lesions with increased 18F FDG uptake are also frequently seen and can be misinterpreted as malignancies. In addition, the use of combined PET/computed tomographic (CT) scanners is associated with pitfalls and artifacts such as attenuation correction and misregistration. Proper interpretation of pediatric 18F FDG PET/CT studies requires knowledge of the normal distribution of 18F FDG uptake in children, as well as of the aforementioned physiologic variants, benign lesions, and PET/CT-related artifacts. Knowing these potential causes of misinterpretation can increase accuracy in PET image interpretation, decrease the number of unnecessary follow-up studies or procedures, and improve patient treatment.

© RSNA, 2009


  • 1 Hustinx R, Bénard F, Alavi A. Whole-body FDG-PET imaging in the management of patients with cancer. Semin Nucl Med 2002;32(1):35–46. Crossref, MedlineGoogle Scholar
  • 2 Gambhir SS, Czernin J, Schwimmer J, Silverman DH, Coleman RE, Phelps ME. A tabulated summary of the FDG PET literature. J Nucl Med 2001; 42(suppl):1S–93S. MedlineGoogle Scholar
  • 3 Hillner BE, Siegel BA, Liu D, et al.. Impact of positron emission tomography/computed tomography and positron emission tomography (PET) alone on expected management of patients with cancer: initial results from the National Oncologic PET Registry. J Clin Oncol 2008;26(13):2155–2161. [Published correction appears in J Clin Oncol 2008;26(25):4229.] Crossref, MedlineGoogle Scholar
  • 4 Tatsumi M, Miller JH, Wahl RL. 18F-FDG PET/CT in evaluating non-CNS pediatric malignancies. J Nucl Med 2007;48(12):1923–1931. Crossref, MedlineGoogle Scholar
  • 5 Depas G, De Barsy C, Jerusalem G, et al.. 18F-FDG PET in children with lymphomas. Eur J Nucl Med Mol Imaging 2005;32(1):31–38. Crossref, MedlineGoogle Scholar
  • 6 Shulkin BL, Mitchell DS, Ungar DR, et al.. Neoplasms in a pediatric population: 2-[F-18]-fluoro-2-deoxy-d-glucose PET studies. Radiology 1995;194 (2):495–500. LinkGoogle Scholar
  • 7 Franzius C, Schober O. Assessment of therapy response by FDG PET in pediatric patients. Q J Nucl Med 2003;47(1):41–45. MedlineGoogle Scholar
  • 8 Hudson MM, Krasin MJ, Kaste SC. PET imaging in pediatric Hodgkin’s lymphoma. Pediatr Radiol 2004;34(3):190–198. Crossref, MedlineGoogle Scholar
  • 9 O’Hara SM, Donnelly LF, Coleman RE. Pediatric body applications of FDG PET. AJR Am J Roentgenol 1999;172(4):1019–1024. Crossref, MedlineGoogle Scholar
  • 10 Abouzied MM, Crawford ES, Nabi HA. 18F-FDG imaging: pitfalls and artifacts. J Nucl Med Technol 2005;33(3):145–155. MedlineGoogle Scholar
  • 11 Pauwels EK, Ribeiro MJ, Stoot JH, McCready VR, Bourguignon M, Mazière B. FDG accumulation and tumor biology. Nucl Med Biol 1998;25(4):317–322. Crossref, MedlineGoogle Scholar
  • 12 Zhuang H, Alavi A. 18-fluorodeoxyglucose positron emission tomographic imaging in the detection and monitoring of infection and inflammation. Semin Nucl Med 2002;32(1):47–59. Crossref, MedlineGoogle Scholar
  • 13 Love C, Tomas MB, Tronco GG, Palestro CJ. FDG PET of infection and inflammation. RadioGraphics 2005;25(5):1357–1368. LinkGoogle Scholar
  • 14 Kubota R, Yamada S, Kubota K, Ishiwata K, Tamahashi N, Ido T. Intratumoral distribution of fluorine-18-fluorodeoxyglucose in vivo: high accumulation in macrophages and granulation tissues studied by microautoradiography. J Nucl Med 1992;33(11): 1972–1980. MedlineGoogle Scholar
  • 15 Rennen HJ, Boerman OC, Oyen WJ, Corstens FH. Scintigraphic imaging of inflammatory processes. Curr Med Chem 2002;1(1):63–75. Google Scholar
  • 16 Stauss J, Franzius C, Pfluger T, et al.. Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology. Eur J Nucl Med Mol Imaging 2008;35(8): 1581–1588. Crossref, MedlineGoogle Scholar
  • 17 Shulkin BL, Hutchinson RJ, Castle VP, Yanik GA, Shapiro B, Sisson JC. Neuroblastoma: positron emission tomography with 2-[fluorine-18]fluoro-2-deoxy-d-glucose compared with metaiodobenzylguanidine scintigraphy. Radiology 1996;199(3):743–750. LinkGoogle Scholar
  • 18 Barrington SF, Begent J, Lynch T, et al.. Guidelines for the use of PET-CT in children. Nucl Med Commun 2008;29(5):418–424. Crossref, MedlineGoogle Scholar
  • 19 Delbeke D, Coleman RE, Guiberteau MJ, et al.. Procedure guideline for tumor imaging with 18F-FDG PET/CT 1.0. J Nucl Med 2006;47(5):885–895. MedlineGoogle Scholar
  • 20 Jadvar H, Connolly LP, Fahey FH, Shulkin BL. PET and PET/CT in pediatric oncology. Semin Nucl Med 2007;37(5):316–331. Crossref, MedlineGoogle Scholar
  • 21 Brix G, Lechel U, Glatting G, et al.. Radiation exposure of patients undergoing whole-body dual-modality 18F-FDG PET/CT examinations. J Nucl Med 2005;46(4):608–613. MedlineGoogle Scholar
  • 22 Fahey FH, Palmer MR, Strauss KJ, Zimmerman RE, Badawi RD, Treves ST. Dosimetry and adequacy of CT-based attenuation correction for pediatric PET: phantom study. Radiology 2007;243(1):96–104. LinkGoogle Scholar
  • 23 Mawlawi O, Erasmus JJ, Munden RF, et al.. Quantifying the effect of IV contrast media on integrated PET/CT: clinical evaluation. AJR Am J Roentgenol 2006;186(2):308–319. Crossref, MedlineGoogle Scholar
  • 24 Yau YY, Chan WS, Tam YM, et al.. Application of intravenous contrast in PET-CT: does it really introduce significant attenuation correction error? J Nucl Med 2005;46(2):283–291. MedlineGoogle Scholar
  • 25 Berthelsen AK, Holm S, Loft A, Klausen TL, Andersen F, Højgaard L. PET/CT with intravenous contrast can be used for PET attenuation correction in cancer patients. Eur J Nucl Med Mol Imaging 2005;32(10):1167–1175. Crossref, MedlineGoogle Scholar
  • 26 Ak I, Stokkel MP, Pauwels EK. Positron emission tomography with 2-[18F]fluoro-2-deoxy-d-glucose in oncology. II. The clinical value in detecting and staging primary tumours. J Cancer Res Clin Oncol 2000;126(10):560–574. Crossref, MedlineGoogle Scholar
  • 27 Burrell SC, Van den Abbeele AD. 2-Deoxy-2-[F-18] fluoro-d-glucose-positron emission tomography of the head and neck: an atlas of normal uptake and variants. Mol Imaging Biol 2005;7(3):244–256. Crossref, MedlineGoogle Scholar
  • 28 Sarji SA. Physiological uptake in FDG PET simulating disease. Biomed Imaging Interv J 2006;2(4):e59. MedlineGoogle Scholar
  • 29 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(3):879–885. LinkGoogle Scholar
  • 30 Cook GJ, Wegner EA, Fogelman I. Pitfalls and artifacts in 18FDG PET and PET/CT oncologic imaging. Semin Nucl Med 2004;34(2):122–133. Crossref, MedlineGoogle Scholar
  • 31 Brink I, Reinhardt MJ, Hoegerle S, Altehoefer C, Moser E, Nitzsche EU. Increased metabolic activity in the thymus studied with FDG PET: age dependency and frequency after chemotherapy. J Nucl Med 2001;42(4):591–595. MedlineGoogle Scholar
  • 32 Fujii H, Ide M, Yasuda S, Takahashi W, Shohtsu A, Kubo A. Increased FDG uptake in the wall of the right atrium in people who participated in a cancer screening program with whole-body PET. Ann Nucl Med 1999;13(1):55–59. Crossref, MedlineGoogle Scholar
  • 33 Fan CM, Fischman AJ, Kwek BH, Abbara S, Aquino SL. Lipomatous hypertrophy of the interatrial septum: increased uptake on FDG PET. AJR Am J Roentgenol 2005;184(1):339–342. Crossref, MedlineGoogle Scholar
  • 34 Lin CY, Ding HJ, Liu CS, Chen YK, Lin CC, Kao CH. Correlation between the intensity of breast FDG uptake and menstrual cycle. Acad Radiol 2007;14(8):940–944. Crossref, MedlineGoogle Scholar
  • 35 Hicks RJ, Binns D, Stabin MG. Pattern of uptake and excretion of 18F-FDG in the lactating breast. J Nucl Med 2001;42(8):1238–1242. MedlineGoogle Scholar
  • 36 Shreve PD, Anzai Y, Wahl RL. Pitfalls in oncologic diagnosis with FDG PET imaging: physiologic and benign variants. RadioGraphics 1999;19(1):61–77. LinkGoogle Scholar
  • 37 Cook GJ, Fogelman I, Maisey MN. Normal physiological and benign pathological variants of 18-fluoro-2-deoxyglucose positron-emission tomography scanning: potential for error in interpretation. Semin Nucl Med 1996;26(4):308–314. Crossref, MedlineGoogle Scholar
  • 38 Löffler M, Weckesser M, Franzius C, Schober O, Zimmer KP. High diagnostic value of 18F-FDG-PET in pediatric patients with chronic inflammatory bowel disease. Ann N Y Acad Sci 2006;1072: 379–385. Crossref, MedlineGoogle Scholar
  • 39 Subhas N, Patel PV, Pannu HK, Jacene HA, Fishman EK, Wahl RL. Imaging of pelvic malignancies with in-line FDG PET-CT: case examples and common pitfalls of FDG PET. RadioGraphics 2005;25 (4):1031–1043. LinkGoogle Scholar
  • 40 Kitajima K, Nakamoto Y, Senda M, Onishi Y, Okizuka H, Sugimura K. Normal uptake of 18F-FDG in the testis: an assessment by PET/CT. Ann Nucl Med 2007;21(7):405–410. Crossref, MedlineGoogle Scholar
  • 41 Lerman H, Metser U, Grisaru D, Fishman A, Lievshitz G, Even-Sapir E. Normal and abnormal 18F-FDG endometrial and ovarian uptake in pre- and postmenopausal patients: assessment by PET/CT. J Nucl Med 2004;45(2):266–271. MedlineGoogle Scholar
  • 42 Ames J, Blodgett T, Meltzer C. 18F-FDG uptake in an ovary containing a hemorrhagic corpus luteal cyst: false-positive PET/CT in a patient with cervical carcinoma. AJR Am J Roentgenol 2005;185(4): 1057–1059. Crossref, MedlineGoogle Scholar
  • 43 Jackson RS, Schlarman TC, Hubble WL, Osman MM. Prevalence and patterns of physiologic muscle uptake detected with whole-body 18F-FDG PET. J Nucl Med Technol 2006;34(1):29–33. MedlineGoogle Scholar
  • 44 Barrington SF, Maisey MN. Skeletal muscle uptake of fluorine-18-FDG: effect of oral diazepam. J Nucl Med 1996;37(7):1127–1129. MedlineGoogle Scholar
  • 45 Yeung HW, Grewal RK, Gonen M, Schoder H, Larsen SM. Patterns of (18)F-FDG uptake in adipose tissue and muscle: a potential source of false-positives for PET. J Nucl Med 2003;44(11):1789–1796. MedlineGoogle Scholar
  • 46 Kawashita NH, Brito MN, Brito SR, et al.. Glucose uptake, glucose transporter GLUT4, and glycolytic enzymes in brown adipose tissue from rats adapted to a high-protein diet. Metabolism 2002;51(11): 1501–1505. Crossref, MedlineGoogle Scholar
  • 47 Truong MT, Erasmus JJ, Munden RF, et al.. Focal FDG uptake in mediastinal brown fat mimicking malignancy: a potential pitfall resolved on PET/CT. AJR Am J Roentgenol 2004;183(4):1127–1132. Crossref, MedlineGoogle Scholar
  • 48 Gelfand MJ, O’Hara SM, Curtwright LA, Maclean JR. Pre-medication to block [(18)F]FDG uptake in the brown adipose tissue of pediatric and adolescent patients. Pediatr Radiol 2005;35(10):984–990. Crossref, MedlineGoogle Scholar
  • 49 Parysow O, Mollerach AM, Jager V, Racioppi S, San Roman J, Gerbaudo VH. Low-dose oral propranolol could reduce brown adipose tissue F-18 FDG uptake in patients undergoing PET scans. Clin Nucl Med 2007;32(5):351–357. Crossref, MedlineGoogle Scholar
  • 50 Kazama T, Swanston N, Podoloff DA, Macapinlac HA. Effect of colony-stimulating factor and conventional- or high-dose chemotherapy on FDG uptake in bone marrow. Eur J Nucl Med Mol Imaging 2005;32(12):1406–1411. Crossref, MedlineGoogle Scholar
  • 51 Sugawara Y, Zasadny KR, Kison PV, Baker LH, Wahl RL. Splenic fluorodeoxyglucose uptake increased by granulocyte colony-stimulating factor therapy: PET imaging results. J Nucl Med 1999;40 (9):1456–1462. MedlineGoogle Scholar
  • 52 Alavi A, Gupta N, Alberini JL, et al.. Positron emission tomography imaging in nonmalignant thoracic disorders. Semin Nucl Med 2002;32(4):293–321. Crossref, MedlineGoogle Scholar
  • 53 Goodin GS, Shulkin BL, Kaufman RA, McCarville MB. PET/CT characterization of fibroosseous defects in children: 18F-FDG uptake can mimic meta-static disease. AJR Am J Roentgenol 2006;187(4): 1124–1128. Crossref, MedlineGoogle Scholar
  • 54 Aoki J, Watanabe H, Shinozaki T, et al.. FDG PET of primary benign and malignant bone tumors: standardized uptake value in 52 lesions. Radiology 2001; 219(3):774–777. LinkGoogle Scholar
  • 55 Schulte M, Brecht-Krauss D, Heymer B, et al.. Grading of tumors and tumorlike lesions of bone: evaluation by FDG PET. J Nucl Med 2000;41(10): 1695–1701. MedlineGoogle Scholar
  • 56 Kapucu LO, Meltzer CC, Townsend DW, Keenan RJ, Luketich JD. Fluorine-18-fluorodeoxyglucose uptake in pneumonia. J Nucl Med 1998;39(7):1267–1269. MedlineGoogle Scholar
  • 57 Prosch H, Mirzaei S, Oschatz E, Strasser G, Huber M, Mostbeck G. Gluteal injection site granulomas: false positive finding on FDG-PET in patients with non-small cell lung cancer. Br J Radiol 2005;78 (932):758–761. Crossref, MedlineGoogle Scholar
  • 58 Funt SA, Hidalgo A, Panicek DM. Subcutaneous nodules at the injection site of low-molecular-weight heparin: a mimic of metastatic disease at CT. J Comput Assist Tomogr 2002;26(4):520–523. Crossref, MedlineGoogle Scholar
  • 59 Kobayashi Y, Ishii K, Oda K, et al.. Aortic wall inflammation due to Takayasu arteritis imaged with 18F-FDG PET coregistered with enhanced CT. J Nucl Med 2005;46(6):917–922. MedlineGoogle Scholar
  • 60 Sureshbabu W, Mawlawi O. PET/CT imaging artifacts. J Nucl Med Technol 2005;33(3):156–164. MedlineGoogle Scholar
  • 61 Yeung HW, Sanches A, Squire OD, Macapinlac HA, Larson SM, Erdi YE. Standardized uptake value in pediatric patients: an investigation to determine the optimum measurement parameter. Eur J Nucl Med Mol Imaging 2002;29(1):61–66. Crossref, MedlineGoogle Scholar

Article History

Received: Dec 22 2008
Revision received: Feb 25 2009
Revision received: Mar 30 2009
Accepted: Apr 7 2009
Published in print: Sept 2009