Clinical Value of Coincidence Detection Emission Tomography Using Fluoine-18-2-Fluoro-2-Deoxy-D-Glucose in the Diagnosis of Solitary Pulmonary Nodules: Correlation with Computed Tomography Findings

Solitary Pulmonary Nodules (size 40 mm) is the most frequent indication of coincidence detection emission tomography (CDET) with fluorine-18 fluoro-2-deoxy-D-glucose (18FDG). The aim of the present study was to establish the efficacy of this system with and without attenuation correction (AC) in correlation with computed tomography (CT) findings for the distinction between benign and malignant pulmonary nodules. Material and methods: Sixty-eight patients were included in this study. All patients presented with suspected pulmonary nodules on thoracic CT. In addition, they had CDET scan using a dual-head coincidence gamma-camera with and without measured attenuation using caesium-137 source. Corrected images were independently interpreted from non-attenuation corrected images in a blinded manner of any clinical data. 18FDG-CDET findings were evaluated by histology when it was available. Otherwise, the final clinical outcome has been considered in data analysis. Results: A total of 71 suspected nodules were observed by CT. Malignant pulmonary disease was found in 38 of these nodules whereas 33 pulmonary nodules were proved to be benign. In addition, one malignant nodule was confirmed with negative CT findings. 18FDG-CDET imaging without AC demonstrated 48 suspected pulmonary lesions included 4 nodules with negative CT findings (sensitivity, 92%; specificity, 68.4%) Versus 43 lesions identified with AC (sensitivity, 92%; specificity, 81.5%). All of the malignant nodules >20 mm in diameter by 18FDG-CDET. In 5 patients (8% of cases), uncorrected images were spotting benign nodules which were considered as negative on corrected images. So lower specificity rate was obtained by non AC mode in comparison with AC mode (68.4% versus 81.5% respectively). Both modalities techniques failed to detect malignancy in 3 patients. In general, the diagnostic accuracy of 18FDG-CDET without AC was relatively comparable to that found with AC (82.6% to 87%, respectively).