[FDG-PET in the diagnosis of pulmonary lesions]

To evaluate the ability of ¹⁸FDG-PET to differentiate benign from malignant pulmonary lesions.

Twenty-seven patients who had abnormal chest roentgenograms underwent ¹⁸FDG-PET. PET scan interpretation was based on visual qualitative analysis of images. Ratio of ¹⁸FDG uptake in the lesion and normal lung tissue assessed visually was used as criteria for differentiation between benign and malignant lesions. Malignant lesions should have lesion/lung ratio larger than 1. 5, while benign lesions should have ratio less than 1. 5. PET results were compared with pathological results, which were the gold standard.

Out of the 27 pulmonary lesions, there were 21 malignant ( 8 cases of adenocarcinoma, 7 squamous cell carcinoma, 2 small cell lung cancer, 1 large cell carcinoma, 3 metastatic carcinoma) and 6 benign lesions. There were 20 cases whose lesion/lung ratio was larger than 1. 5 and 7 cases less than 1. 5, with an accuracy, sensitivity, specificity, positive predictive value and negative predictive value of 96. 3%, 95. 2%, 100. 0%, 100. 0%and 85. 7% respectively, for detecting malignant pulmonary lesions.

¹⁸FDG-PET imaging accurately differentiates malignant from benign pulmonary lesions. PET can be a useful noninvasive test to evaluate indeterminate pulmonary lesions, which will provide us with more accurate and valuable diagnostic information.