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EDUCATION EXHIBIT - Continuing Medical Education

PET-CT Fusion Imaging in Differentiating Physiologic from Pathologic FDG Uptake

Published Online:Sep 1 2004https://doi.org/10.1148/rg.245035725

Abstract

Interpretation of positron emission tomographic (PET) scans in the absence of correlative anatomic information can be challenging. PET–computed tomography (CT) fusion imaging is a novel multimodality technology that allows the correlation of findings from two concurrent imaging modalities in a comprehensive examination. CT demonstrates exquisite anatomic detail but does not provide functional information, whereas 2-[fluorine 18]fluoro-2-deoxy-d-glucose (FDG) PET reveals aspects of tumor function and allows metabolic measurements. Subtle findings at FDG PET that might otherwise be disregarded or interpreted as physiologic variants may lead to detection of a malignant process after being correlated with simultaneously acquired CT findings. Alternatively, equivocal CT findings, which could represent malignant tumor, reactive changes, or fibrosis, can be clarified with the help of the additional metabolic information provided by concurrent FDG PET. Accurate interpretation of FDG PET scans requires a thorough knowledge of the normal physiologic distribution of FDG and of normal variants that may reduce the accuracy of PET studies, thereby significantly affecting patient treatment. Although in rare instances PET-CT cannot help resolve the diagnostic dilemma, it is enjoying widespread acceptance in the medical imaging community, usually allowing differentiation of physiologic variants from juxtaposed or mimetic neoplastic lesions and more accurate tumor localization.

© RSNA, 2004

References

  • 1 Wahl RL. Targeting glucose transporters for tumor imaging: “sweet” idea, “sour” result. J Nucl Med 1996; 37:1038-1041.
    Medline Google Scholar
  • 2 Kostakoglu L, Agress H, Goldsmith SJ. Clinical role of FDG PET in evaluation of cancer patients. RadioGraphics 2003; 23:315-339.
    Google Scholar
  • 3 Shreve PD, Anzai Y, Wahl RL. Pitfalls in oncologic diagnosis with FDG PET imaging: physiologic and benign variants. RadioGraphics 1999; 19:61-77.
    Google Scholar
  • 4 Goerres GW, von Schulthess GK, Hany TH. Positron emission tomography and PET CT of the head and neck: FDG uptake in normal anatomy, in benign lesions and in changes resulting from treatment. AJR Am J Roentgenol 2002; 179:1337-1343.
    Medline Google Scholar
  • 5 Kluetz PG, Meltzer CC, Villemenagne VL, et al. Combined PET/CT imaging in oncology: impact on patient management. Clin Positron Imaging 2000; 3:223-230.
    Medline Google Scholar
  • 6 Abdel-Dayem HM, Rosen G, El-Zeftawy H, et al. Fluorine-18 fluorodeoxyglucose splenic uptake from extramedullary hematopoiesis after granulocyte colony-stimulating factor stimulation. Clin Nucl Med 1999; 24:319-322.
    Medline Google Scholar
  • 7 Gordon BA, Flanagan FL, Dehdashti F. Whole-body positron emission tomography: normal variations, pitfalls, and technical considerations. AJR Am J Roentgenol 1997; 169:1675-1680.
    Medline Google Scholar
  • 8 Kostakoglu L, Wong JC, Barrington SF, Cronin BF, Dynes AM, Maisey MN. Speech-related visualization of laryngeal muscles with fluorine-18-FDG. J Nucl Med 1996; 37:1771-1773.
    Medline Google Scholar
  • 9 Zhu Z, Chou C, Yen TC, Cui R. Elevated F-18 FDG uptake in laryngeal muscles mimicking thyroid cancer metastases. Clin Nucl Med 2001; 26:689-691.
    Medline Google Scholar
  • 10 Stahl A, Dzewas B, Schwaiger M, Weber WA. Excretion of FDG into saliva and its significance for PET imaging. Nuklearmedizin 2002; 41:214-216.
    Medline Google Scholar
  • 11 Wang GJ, Cai L. Relatively low-dose cyclophosphamide is likely to induce apoptotic cell death in rat thymus through Fas/Fas ligand pathway. Mutat Res 1999; 427:125-133.
    Medline Google Scholar
  • 12 Hughes FM, Cidlowski JA. Glucocorticoid-induced thymocyte apoptosis: protease-dependent activation of cell shrinkage and DNA degradation. J Steroid Biochem Mol Biol 1998; 65:207-217.
    Medline Google Scholar
  • 13 Hany TF, Gharehpapagh E, Kamel EM, Buck A, Himms-Hagen J, von Schulthess GK. Brown adipose tissue: a factor to consider in symmetrical tracer uptake in the neck and upper chest region. Eur J Nucl Med Mol Imaging 2002; 29:1393- 1398.
    Medline Google Scholar
  • 14 Cohade C, Osman M, Pannu HK, Wahl RL. Uptake in supraclavicular area fat (“USA-Fat”): description on 18F-FDG PET/CT. J Nucl Med 2003; 44:170-176.
    Medline Google Scholar
  • 15 Himms-Hagen J. Brown adipose tissue thermogenesis: interdisciplinary studies. FASEB J 1990; 4:2890-2898.
    Medline Google Scholar
  • 16 Barrington SF, Maisey MN. Skeletal muscle uptake of fluorine-18-FDG: effect of oral diazepam. J Nucl Med 1996; 37:1127-1129.
    Medline Google Scholar
  • 17 Poole DC, Kindig CA, Behnke BJ. Effects of emphysema on diaphragm microvascular oxygen pressure. Am J Respir Crit Care Med 2001; 163:1081-1086.
    Medline Google Scholar
  • 18 Stahl A, Ott K, Weber WA, et al. FDG PET imaging of locally advanced gastric carcinomas: correlation with endoscopic and histopathological findings. Eur J Nucl Med Mol Imaging 2003; 30:288-295.
    Medline Google Scholar
  • 19 Tatlidil R, Jadvar H, Bading JR, Conti PS. Incidental colonic fluorodeoxyglucose uptake: correlation with colonoscopic and histopathologic findings. Radiology 2002; 224:783-787.
    Google Scholar
  • 20 Guan L, Dadparvar S, Reich P, et al. Unrecognized renal transplants as a potential source of false-positive interpretation of FDG PET. Clin Nucl Med 2003; 28:655-657.
    Medline Google Scholar
  • 21 Chander S, Meltzer CC, McCook BM. Physiologic uterine uptake of FDG during menstruation demonstrated with serial combined positron emission tomography and computed tomography. Clin Nucl Med 2002; 27:22-24.
    Medline Google Scholar
  • 22 Townsend DW, Beyer T. A combined PET/CT scanner: the path to true image fusion. Br J Radiol 2002; 75:S24-S30.
    Medline Google Scholar
  • 23 Bar-Shalom R, Yefremov N, Guralnik L, et al. Clinical performance of PET/CT in evaluation of cancer: additional value for diagnostic imaging and patient management. J Nucl Med 2003; 44:1200-1209.
    Medline Google Scholar
  • 24 Charron M, Beyer T, Bohnen NN, et al. Image analysis in patients with cancer studied with a combined PET and CT scanner. Clin Nucl Med 2000; 25:905-910.
    Medline Google Scholar
  • 25 Goerres GW, Kamel E, Heidelberg TN, Schwitter MR, Burger C, von Schulthess GK. PET/CT image co-registration in the thorax: influence of respiration. Eur J Nucl Med Mol Imaging 2002; 29:351-360.
    Medline Google Scholar
  • 26 Beyer T, Antoch G, Blodgett T, Freudenberg LF, Akhurst T, Mueller S. Dual-modality PET/CT imaging: the effect of respiratory motion on combined image quality in clinical oncology. Eur J Nucl Med Mol Imaging 2003; 30:588-596.
    Medline Google Scholar
  • 27 Wahl RL, Townsend DW, Meltzer CC, Von Schulthess GK, Fishman EK. CT/PET fusion imaging (abstr). Radiology 2002; 225(P):42.
    Google Scholar

Article History

Published in print: Sept 2004