Shorter-time dual-phase FDG PET/CT in characterizing solid or ground-glass nodules based on surgical results ☆ Chen-Feng Chiu a,b , Yu-Yi Lin c , Wu-Huei Hsu d,e , Chih-Yi Chen f , Jun-Jun Yeh e,g, ⁎ ,1 , Chia-Hung Kao a,c,e, ⁎ ,1 a Institute of Clinical Medicine Science, China Medical University, Taichung, Taiwan b Department of Internal Medicine, Fong Yuan Hospital, Department of Health, Executive Yuan, Taiwan c Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan d Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan e School of Medicine, China Medical, University, Taichung, Taiwan f Cancer Center, China Medical University Hospital, Taichung, Taiwan g Pingtung Christian Hospital, Meiho University, Pingtung, Taiwan Received 10 September 2011; received in revised form 19 October 2011; accepted 30 November 2011 Abstract Objectives: We compared the accuracy of shorter-time dual-phase 18 F-FDG PET/CT in evaluating 94 different lung nodules classified as solid or ground-glass nodules (GGNs). Materials and Methods: Early and delayed maximum standardized uptake values (SUV max ) as well as the retention index (RI) of each nodule were determined in 75 solid nodules and 19 GGNs. Results: In solid nodules, early SUV max , delayed SUV max , and RI were higher in malignant than in benign lesions. In GGNs, these values were not significantly lower in the malignant than in the benign lesions. Conclusion: In the patient group with solid nodules, shorter-time dual-phase 18 F-FDG PET/CT could significantly differentiate the malignant from the benign ones. © 2012 Elsevier Inc. All rights reserved. Keywords: FDG PET/CT; Ground-glass nodules; Dual-phase 1. Introduction 18 F-Fluorodeoxyglucose-Positron emission tomography (FDG-PET) has played an important role in differentiating lung cancer from benign lung lesions for nearly a decade [1–4]. FDG-PET detects malignancy by high 18 F-FDG uptake which reflects increased glucose metabolic activity of cancer cells. However, there exist limitations of FDG-PET toward lesions with extreme metabolic rate, such as slow ones—bronchioloalveolar carcinoma, carcinoid tumors—and faster ones such as inflammatory lesions. The former (less glucose activity) may give false-negative FDG-PET results, while the latter (higher glucose activity) false positive. Pulmonary nodules may manifest as solid-pattern or ground-glass nodules (GGNs) in the lung window of computed tomography (CT). Lesions with a solid pattern have been evaluated by applying 18 F-FDG PET/CT and using the maximum standardized uptake value (SUV max ) to differentiate malignancy from benign lesions. A pulmonary lesion with a SUV max N2.5 is considered to be malignant. But many researchers reported that GGNs with minor metabolic activities and lower SUV max may have high malignant potential [5]. Dual-phase PET/CT was introduced as a method to improve the accuracy of evaluating pulmonary lesions with Clinical Imaging 36 (2012) 509 – 514 ☆ Conflicts of interest: All authors declare there were no actual or potential conflicts of interest in this study. ⁎ Corresponding authors. Department of Nuclear Medicine and PET Center, Medical University Hospital, No. 2, Yuh-Der Road, Taichung 404, Taiwan, China. Tel.: +886 4 22052121x7412; fax: +886 4 22336174. E-mail addresses: anvin.funlan@msa.hinet.net (J.-J. Yeh), d10040@mail.cmuh.org.tw (C.-H. Kao). 1 J.-J. Yeh and C.-H. Kao contributed equally to this work as co- corresponding authors. 0899-7071/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.clinimag.2011.11.032