Evaluation of Pleural Disease With 18-Fluorodeoxyglucose Positron Emission Tomography Imaging* Bernard Duysinx, MD; Delphine Nguyen, MD; Renaud Louis, MD, PhD; Didier Cataldo, MD, PhD; Tarik Belhocine, MD; Pierre Bartsch, MD; and Thierry Bury, MD, PhD Study objectives: To study the ability of positron emission tomography (PET) using 18-fluorode- oxyglucose (FDG) to distinguish between benign and malignant disease in exudative pleural effusions and pleural thickening. Design: Prospective study of 98 consecutive patients presenting with either pleural thickening or an exudative pleural effusion. Setting: Department of pulmonary medicine of a university hospital. Methods: FDG-PET was performed on each subject before invasive procedures were used to determine the etiologic diagnosis. FDG-PET data were analyzed by visual interpretation. Results: Sixty-three of 98 patients were found to have malignant pleural disease after histologic analysis. Sixty-one of 63 patients with histologically confirmed malignant disease showed FDG uptake within the area of pleural thickening. Uptake was graded as intense in 51 cases and moderate in 10 cases. Only two patients with malignant pleural disease did not show increased FDG uptake. FDG-PET imaging showed an absence of FDG uptake, and correctly classified 31 of 35 benign lesions. For the remaining four lesions, intense FDG uptake was seen in one case of parapneumonic effusion, while moderate and localized uptake was observed in one parapneu- monic, one tuberculous, and one uremic pleurisy. The sensitivity of the method to identify malignancy was 96.8% with a negative predictive value of 93.9%, while its specificity was 88.5% and its positive predictive value was 93.8%. Conclusions: Our results suggest that FDG-PET is an effective tool for differentiating between benign and malignant pleural diseases. (CHEST 2004; 125:489 – 493) Key words: fluorodeoxyglucose; pleural diseases; positron emission tomography Abbreviations: CI = confidence interval; FDG = 18-fluorodeoxyglucose; PET = positron emission tomography P leural effusion or pleural thickening are the usual radiographic manifestations of pleural diseases, but accurate diagnosis is difficult without resort to invasive procedures. It is often necessary to perform thoracic CT scan; thoracocentesis with biochemical, microbiological, and cytologic analyses; blind-needle biopsies; and sometimes eventually biopsies per- formed during either pleuroscopy or open-chest surgery. Invasive procedures are justified for several reason. First, there is a lack of accepted and reliable criteria for malignancy only based on morphologic imaging (CT and MRI). Second, the sensitivity of cytologic examination of pleural fluid and blind needle biopsy is weak. 1–8 By contrast, thoracoscopy alone was found to be diagnostic in 95% of cases. 7 However, this procedure has several drawbacks. It is invasive, must be performed with caution in older patients, and requires surgical facilities and trained staff. Positron emission tomography (PET) using 18- fluorodeoxyglucose (FDG) 9 can accurately differen- tiate benign from malignant pulmonary tumors using the marked biochemical difference in glucose me- tabolism between normal and tumor cells. Studies have shown the utility of FDG-PET in the evaluation of solitary pulmonary nodules, 10 –12 and also in me- diastinal staging 13,14 and detection of extrathoracic *From the Departments of Pulmonary Medicine (Drs. Duysinx, Nguyen, Louis, Cataldo, Bartsch, and Bury) and Nuclear Medi- cine (Dr. Belhocine), CHU, Lie ` ge, Belgium. Dr. Cataldo is a postdoctoral researcher from the Belgian National Fund for Scientific Research (FNRS), Belgium. Manuscript received August 28, 2002; revision accepted Septem- ber 3, 2003. Reproduction of this article is prohibited without written permis- sion from the American College of Chest Physicians (e-mail: permissions@chestnet.org). Correspondence to: Bernard Duysinx, MD, Department of Pul- monary Medicine, CHU Sart Tilman B35, B-4000 Lie `ge, Bel- gium; e-mail: bduysinx@swing.be www.chestjournal.org CHEST / 125 / 2 / FEBRUARY, 2004 489 Downloaded From: http://journal.publications.chestnet.org/ on 01/04/2014