Spectrum of 18 F-FDG Uptake in Bilateral Lung Parenchymal Diseases on PET/CT Meghana Prabhu, DNB, Shobhana Raju, MD, Dhritiman Chakraborty, MD, Saurabh Arora, MD, and Rakesh Kumar, MD, PhD Abstract: Bilateral lung parenchymal involvement is seen in infective as well as noninfective conditions, appearing as focal or diffuse lung disease. PET/CT with FDG helps in characterization (increased glucose utilization is seen by both inflammatory and neoplastic cells). In this article, we de- scribe the spectrum of patterns of FDG uptake and associated CT changes involving bilateral lung parenchyma. Benign conditions described are aspira- tion pneumonia; pulmonary toxicity by bleomycin; infections, namely, sar- coidosis, miliary pulmonary tuberculosis, and pulmonary nocardiosis; and inflammatory conditions such as pulmonary Langerhans cell histiocytosis and pulmonary alveolar proteinosis. Neoplastic conditions described are bi- lateral pulmonary metastases and lymphangitic carcinomatosis. Key Words: bilateral lung parenchymal disease, 18 F-FDG uptake PET/CT (Clin Nucl Med 2020;45: e15–e19) REFERENCES 1. Franquet T , Giménez A, Rosón N, et al. Aspiration diseases: findings, pitfalls, and differential diagnosis. Radiographics. 20:673–685. 2. Rossi SE, Erasmus JJ, Mcadams HP, et al. Pulmonary drug toxicity: radiologic and pathologic manifestations. Radiographics. 2000;20:1245–1259. 3. Sobic-Saranovic D, Artiko V, Obradovic V. FDG PET imaging in sarcoidosis. Semin Nucl Med. 2013;43:404–411. 4. Harkirat S, Anana SS, Indrajit LK, et al. Pictorial essay: PET/CT in tuberculo- sis. Indian J Radiol Imaging. 2008;18:141–147. 5. Yang M, Xu M, Wei W, et al. Clinical findings of 40 patientswith nocardiosis. Exp Ther Med. 2014;8:25–30. 6. Albano D, Bosio G, Giubbini R, et al. Role of 18 F-FDG PET/CT in patients affected by Langerhans cell histiocytosis. Jpn J Radiol. 2017;35:574–583. 7. Hsu CW , Liu FY, Wang CW, et al. F-18 FDG PET/CT in pulmonary alveolar proteinosis. Clin Nucl Med. 2009;34:103–104. 8. Naidich DP , Srichai MB, Krinsky GA. Computed Tomography and Magnetic Resonance of the Thorax . Lippincott Williams & Wilkins; 2007. ISBN:0781757657. 9. Johkoh T , Ikezoe J, Tomiyama N, et al. CT findings in lymphangitic carcino- matosis of the lung: correlation with histologic findings and pulmonary function tests. AJR Am J Roentgenol. 1992;158:1217–1222. Received for publication March 11, 2019; revision accepted July 1, 2019. From the Department of Nuclear Medicine, AIIMS, New Delhi, India. Conflicts of interest and sources of funding: none declared. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent: The institutional review board of our institute approved this retrospective study, and the requirement to obtain informed consent was waived. Correspondence to: Rakesh Kumar, MD, PhD, Department of Nuclear Medicine, AIIMS Campus, E-81, Ansari Nagar (East), New Delhi 110029, India. E-mail: rkphulia@yahoo.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/20/4501–0e15 DOI: 10.1097/RLU.0000000000002758 INTERESTING IMAGE Clinical Nuclear Medicine • Volume 45, Number 1, January 2020 www.nuclearmed.com e15 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.