Abstract
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Purpose: Malignant pleural effusion (MPE) is common and represents advanced malignant diseases. An efficacious procedure that can establish a definite diagnosis as early as possible with a minimum of risk and discomfort would be highly desirable. This study was designed to investigate the diagnostic value of 18F-fluorodeoxyglucose (18F-FDG) panoramic positron emission tomography/computed tomography (PET/CT) combined with thoracic positron emission tomography/magnetic resonance imaging (PET/MRI) for diagnosing malignant pleural effusion (MPE).
Methods: In this prospective study, we studied 36 patients with suspected MPE who underwent thoracic PET/MRI subsequently to panoramic PET/CT (interval time: 60‒120 min). All suspected malignant lesions and characteristics of pleural were analyzed with PET/CT and PET/MRI, including pleural diffusion, thickening, diffused weighted imaging (DWI) hyperintensity and maximum standardized uptake values (SUVmax). Compared to the gold diagnosis criteria, the results of PET/CT and PET/MRI were evaluated in the diagnosis of MPE.
Results: 28 patients were finally confirmed to be MPE and the remaining 8 had benign pleural effusions (BPE: 5 parapneumonic effusion, PE; 3 tuberculosis pleural effusion, TPE). The SUVmax of pleural lesions was significantly different among these 3 groups (MPE, 8.1 ± 0.8; PE, 3.8 ± 1.0; TPE, 16.5 ± 1.0), while the difference between MPE and BPE was not significant (8.1 ± 0.8 and 8.6 ± 1.2, P=0.858). Among all characteristics of pleural lesion, DWI hyperintensity showed highest sensitivity (96.4%) and negative predictive rate (66.7%). Pleural nodules showed highest specificity (87.5%) and positive predictive rate (93.3%). In MPE group, panoramic PET/CT successfully identified 14 patients with distant metastasis. Overall, panoramic PET/CT combined with thoracic PET/MRI correctly diagnosed 35 of 36 patients with suspected MPE (diagnostic accuracy, 97.2%; 95% confidence interval [CI],91.6 to 102.9 ). Moreover, the area under the curve (AUC) of the synthetical diagnosis for MPE was 0.938 (95% CI, 0.804 to 0.991), higher than that of single characteristic. Conclusion: Our preliminary results support that panoramic PET/CT combined with thoracic PET/MRI has the potential to be an accurate, comprehensive and reliable noninvasive procedure for diagnosing of MPE.