Performance of sodium iodide based¹⁸F-fluorodeoxyglucose positron emission tomography in the characterization of indeterminate pulmonary nodules or masses

Abstract

The purpose of this study was to document the accuracy of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) with sodium iodide detectors in characterizing indeterminate lung nodules or masses and in identifying additional extra-lesional findings. 50 consecutive patients without a confident diagnosis of malignancy on CT underwent (18)FDG PET with and without attenuation correction. The diagnosis of malignancy was made using visual diagnostic criteria, and tumour-to-blood pool ratios were calculated. The final diagnosis was established by surgery, biopsy or long-term follow-up. Any additional findings made at PET were recorded and similarly verified. Using blinded visual diagnostic criteria for the differentiation of malignant from benign nodules, sodium iodide PET achieved a sensitivity of 91% (30 of 33 cases), a specificity of 88% (15 of 17 cases), a positive predictive value for malignancy of 94% (30 of 32 cases) and a negative predictive value of 83% (15 of 18 cases). False positives occurred with active tuberculosis and sarcoidosis. False negatives were a 3 cm bronchoalveolar carcinoma, a 1.3 cm sarcoma metastasis and a 1 cm carcinoma. Use of tumour-to-blood pool ratios did not improve performance. PET suggested the presence of nodal or distant metastases in 13 of 33 patients with a malignant pulmonary lesion. These PET findings were confirmed in 11 patients. These results indicate that sodium iodide PET is an accurate tool for the characterization of indeterminate pulmonary masses or nodules and simultaneously provides non-invasive staging information that can alter patient management in up to one-third of such patients. Performance of sodium iodide PET is comparable with reported results for PET scanners using other detector materials.

PET/CT Imaging of Lung Cancer

“…Lastly, certain cancers, such as bronchoalveolar carcinomas and carcinoid tumors, may not be evaluable by FDG imaging, because they have a low metabolic activity that may not reflect their biologic behavior and ultimate prognosis. [9][10][11] Despite these shortcomings of evaluating the primary tumor with FDG imaging, there are important contributions from FDG imaging to the CT evaluation of the primary tumor. FDG-PET imaging is of potential use in assessing the metabolic activity of the primary lung cancer, which reflects cell turnover rate [12][13][14] and may indicate the biologic aggressiveness of the cancer.…”

Mediastinal hibernoma simulates a malignant lesion on dual time point FDG imaging

“…Infection, inflammation, and granulomatous lesions including sarcoidosis [2], tuberculosis [3], and aspergillosis [4] exhibits high FDG uptake. Conversely, bronchoalveolar carcinoma and carcinoid tumors may not show significantly increased FDG activity [5]. Despite these exceptions, FDG PET provides critical information that impacts patient management.…”

Tuberculosis spine: Therapeutically refractory disease

“…But FDG PET also shows increased uptake in neoplastic as well as other granulomatous diseases like sarcoidosis, histoplasmosis, aspergillosis, and coccidioidomycosis. PET cannot be used to differentiate between neoplastic and nonneoplastic causes of increased uptake 2526. Hence in patients with ambiguous MRI findings or enhancing areas on MRI after full clinical resolution of the symptoms and completion of ATT increased uptake on FDG PET corroborates presence of active infection.…”