18 F-fluoro-deoxy-glucose focal uptake in very small pulmonary nodules: fact or artifact? Case reports
18F-fluoro-deoxy-glucose (18 F-FDG) positron emission tomography integrated/combined with computed tomography (PET-CT) provides the best diagnostic results in the metabolic characterization of undetermined solid pulmonary nodules. The diagnostic performance of 18 F-FDG is similar for nodules measuring at least 1 cm and for larger masses, but few data exist for nodules smaller than 1 cm.
We report five cases of oncologic patients showing focal lung 18 F-FDG uptake on PET-CT in nodules smaller than 1 cm. We also discuss the most common causes of 18 F-FDG false-positive and false-negative results in the pulmonary parenchyma.
In patient 1, contrast-enhanced CT performed 10 days before PET-CT did not show any abnormality in the site of uptake; in patient 2, high-resolution CT performed 1 month after PET showed a bronchiole filled with dense material interpreted as a mucoid impaction; in patient 3, contrast-enhanced CT performed 15 days before PET-CT did not identify any nodules; in patients 4 and 5, contrast-enhanced CT revealed a nodule smaller than 1 cm which could not be characterized. The 18 F-FDG uptake at follow-up confirmed the malignant nature of pulmonary nodules smaller than 1 cm which were undetectable, misinterpreted, not recognized or undetermined at contrast-enhanced CT.
In all five oncologic patients, 18 F-FDG was able to metabolically characterize as malignant those nodules smaller than 1 cm, underlining that: 18 F-FDG uptake is not only a function of tumor size but it is strongly related to the tumor biology; functional alterations may precede morphologic abnormalities. In the oncologic population, especially in higher-risk patients, PET can be performed even when the nodules are smaller than 1 cm, because it might give an earlier characterization and, sometimes, could guide in the identification of alterations missed on CT.
- Rohren EM, Turkington TG, Coleman RE: Clinical application of PET in oncology. Radiology 2004, 231:305–332. CrossRef
- Kim SK, Allen-Auerbach M, Goldin J, Fueger BJ, Dahlbom M, Brown M, Czernin J, Schiepers C: Accuracy of PET/CT in characterization of solitary pulmonary lesions. J Nucl Med 2007, 48:214–220.
- Gould MK, Maclean CC, Kuschner WG, Rydzak CE, Owens DK: Accuracy of positron emission tomography for diagnosis of pulmonary nodules and mass lesions: a meta-analysis. JAMA 2001, 285:914–924. CrossRef
- Kagna O, Solomonov A, Keidar Z, Bar-Shalom R, Fruchter O, Yigla M, Israel O, Guralnik L: The value of FDG-PET/CT in assessing single pulmonary nodules in patients at high risk of lung cancer. Eur J Nucl Med Mol Imaging 2009, 36:997–1004. CrossRef
- Lillington GA: Management of solitary pulmonary nodules. Dis Mon 1991, 5:271–318.
- Cardinale L, Ardissone F, Novello S, Busso M, Solitro F, Longo M, Sardo D, Giors M, Fava C: The pulmonary nodule: clinical and radiological characteristics affecting a diagnosis of malignancy. Radiol Med 2009, 114:871–889. CrossRef
- Yeong JJ, Chin AY, Kyung SL: Solitary pulmonary nodules: detection, characterization, and guidance for further diagnostic workup and treatment. AJR 2007, 188:57–68. CrossRef
- Reinhardt MJ, Wiethoelter N, Matthies A, Joe AY, Strunk H, Jaeger U, Biersack H-J: PET recognition of pulmonary metastases on PET/CT imaging: impact of attenuation-corrected and non-attenuation-corrected PET images. Eur J Nucl Med Mol Imaging 2006, 33:134–139. CrossRef
- Herder GJ, Golding RP, Hoekstra OS, Comans EF, Teule GJ, Postmus PE, Smit EF: The performance of 18 F-fluorodeoxyglucose positron emission tomography in small solitary pulmonary nodules. Eur J Nucl Med Mol Imaging 2004, 31:1231–1236. CrossRef
- Divisi D, Di Tommaso S, Di Leonardo G, Brianzoni E, De Vico A, Crisci R: 18-fluorine fluorodeoxyglucose positron emission tomography with computerized tomography versus computerized tomography alone for the management of solitary lung nodules with diameters inferior to 1.5 cm. Thorac Cardiovasc Surg 2010, 58:422–426. CrossRef
- Alavi A, Gupta N, Alberini JL, Hickeson M, Adam LE, Bhargava P, Zhuang H: Positron emission tomography imaging in nonmalignant thoracic disorders. Semin Nucl Med 2002, 32:293–321. CrossRef
- Chang JM, Lee HJ, Goo JM, Lee HY, Lee JJ, Chung JK, Im JG: False positive and false negative fdg-pet scans in various thoracic diseases. Korean J Radiol 2006, 7:57–69. CrossRef
- Higashi K, Ueda Y, Seki H, Yuasa K, Oguchi M, Noguchi T, Taniguchi M, Tonami H, Okimura T, Yamamoto I: Fluorine-18-FDG PET imaging is negative in bronchioloalveolar lung carcinoma. J Nucl Med 1998, 39:1016–1020.
- Fischer BM, Olsen MWB, Ley CD, Klausen TL, Mortensen J, Højgaard L, Kristjansen PEG: How few cancer cells can be detected by positron emission tomography? A frequent question addressed by an in vitro study. Eur J Nucl Med Mol Imaging 2006, 33:697–702. CrossRef
- Wahl RL, Jacene H, Kasamon Y, Lodge MA: From RECIST to PERCIST: evolving considerations for pet response criteria in solid tumors. J Nucl Med 2009, 50:122S-150S. CrossRef
- Nehmeh SA, Erdi YE, Ling CC, Rosenzweig KE, Schoder H, Larson SM, Macapinlac HA, Squire OD, Humm JL: Effect of respiratory gating on quantifying pet images of lung cancer. J Nucl Med 2002, 43:876–881.
- Karantanis D, Subramaniam RM, Mullan BP, Peller PJ, Wiseman GA: Focal F-18 fluoro-deoxy-glucose accumulation in the lung parenchyma in the absence of CT Abnormality in PET/CT. J Comput Assist Tomogr 2007, 31:800–805. CrossRef
- Shim SS, Lee KS, Kim BT, Choi JY, Chung MJ, Lee EJ: Focal parenchymal lung lesions showing a potential of false-positive and false-negative interpretations on integrated PET/CT. AJR 2006, 186:639–648. CrossRef
- Bakheet SM, Powe J: Benign causes of 18-fdg uptake on whole body imaging. Semin Nucl Med 1998, XXVIII:352–358.
- Kamel EM, Mckee TA, Calcagni ML, Schmidt S, Markl S, Castaldo S, Bischof Delaloye A: Occult lung infarction may induce false interpretation of18 F-FDG PET in primary staging of pulmonary malignancies. Eur J Nucl Med Mol Imaging 2005, 32:641–646. CrossRef
- Farsad M, Ambrosini V, Nanni C, Castellucci P, Boschi S, Rubello D, Fabbri M, Franchi R, Fanti S: Focal lung uptake of 18 F-fluorodeoxyglucose (18 F-FDG) without computed tomography findings. Nucl Med Commun 2005, 26:827–830. CrossRef
- Ha JM, Jeong SY, Seo YS, Kwon SY, Chong A, Oh JR, Song HC, Bom HS, Min JJ: Incidental focal F-18 FDG accumulation in lung parenchyma without abnormal CT findings. Ann Nucl Med 2009, 23:599–603. CrossRef
- Hany TF, Heuberger J, von Schulthess GK: Iatrogenic FDG foci in the lungs: a pitfall of PET image interpretation. Eur Radiol 2003, 13:2122–2127. CrossRef
- Juweid ME, Cheson BD: Positron-emission tomography and assessment of cancer therapy. N Engl J Med 2006, 354:496–507. CrossRef
- Wormanns D, Diederich S: Characterization of small pulmonary nodules by CT. Eur Radiol 2004, 14:1380–1391.
- Libby DM, Smith JP, Altorki NK, Pasmantier MW, Yankelevitz D, Henschke CI: Managing the small pulmonary nodule discovered by CT. Chest 2004, 125:1522–1529. CrossRef
- Edey AJ, Hansell DM: Incidentally detected small pulmonary nodules on CT. Clin Radiol 2009, 64:872–884. CrossRef
- Girvin F, Ko JP: Pulmonary nodules: detection, assessment, and CAD. AJR 2008, 191:1057–1069. CrossRef
- Feine U, Lietzenmayer R, Hanke JP, Held J, Wohrle H, Muller-Schauenburg W: Fluorine-18-FDG and iodine-131-iodide uptake in thyroid cancer. J Nucl Med 1996, 37:1468–1472.
- 18 F-fluoro-deoxy-glucose focal uptake in very small pulmonary nodules: fact or artifact? Case reports
- Open Access
- Available under Open Access This content is freely available online to anyone, anywhere at any time.
World Journal of Surgical Oncology
- Online Date
- April 2012
- Online ISSN
- BioMed Central
- Additional Links
- 18 F-FDG focal uptake
- Small pulmonary nodules
- Author Affiliations
- 1. Institute of Nuclear Medicine, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168, Rome, Italy
- 2. Institute of Radiology, Università Cattolica del Sacro Cuore, Rome, Italy