Marco Spadafora*, Laura Evangelista, Salvatore Fiordoro, Francesco Porcaro, Marilena Sicignano and Luigi Mansi Pages 243 - 248 ( 6 )
Purpose: The Italian Tailored Assessment of Lung Indeterminate Accidental Nodule (ITALIAN) trial is a trial drawn to determine the performance of 18F-FDG-PET/CT in patients with solitary pulmonary nodules (SPN), stratified for a different kind of risk. An additional end-point was to compare the diagnostic information and estimated dosimetry, provided by a segmental PET/CT (s-PET/CT) acquisition instead of a whole body PET/CT (wb-PET/CT), in order to evaluate if segmental thoracic PET/CT can be used in patients with SPN.
Methods: 18F-FDG PET/CT of 502 patients, stratified for pre-test cancer risk, was retrospectively analyzed. FDG uptake in SPN was assessed by a 4-point scoring (4PS) system and a semiquantitative analysis using the ratio between SUVmax in SPN and SUVmean in mediastinal blood pool (BP), and between SUVmax in SPN and SUVmean in the liver (L). Histopathology and/or follow-up data were used as a standard of reference. Data obtained on the thoracic part of wb-PET/CT, defined as s - PET/CT, were compared with those deriving from wb-PET/CT.
Results: SPNs were malignant in 180 patients (36%), benign in 175 (35%), and indeterminate in 147 (29%). The 355 patients diagnosed with a definitive SPN nature (malignant or benign) were considered for the analysis of PET performance. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, and accuracy were 85.6%, 85.7%, 86%, 85.2%, and 85.6%, respectively. Sensitivity and PPV were higher in intermediate and high-risk patients.
18F-FDG uptake indicative of thoracic and extra-thoracic lesions was detectable in 13% and 3% of the patients. Compared to wb-PET/CT, s-PET/CT could save about 2/3 of 18F-FDG dose, radiation exposure or scan-time, without affecting the clinical impact of PET/CT.
Conclusion: In patients with SPN, the pre-test likelihood of malignancy stratification allows to better define PET clinical setting and its diagnostic power. In subjects with low-intermediate pre-test likelihood of malignancy, s-PET/CT might be planned in advance. The adoption of this segmental strategy could reduce radiation exposure, scan-time, and might allow individually targeted protocols.
Lung cancer, single pulmonary nodules, likelihood, FDG, PET/CT.
Nuclear Medicine Unit, Ospedale del Mare, Naples, Nuclear Medicine Unit, Veneto Institute of Oncology IOV - IRCCS, Padua, Nuclear Medicine Unit, Ospedale del Mare, Naples, Nuclear Medicine Unit, Ospedale del Mare, Naples, Nuclear Medicine Unit, Ospedale del Mare, Naples, Section Health and Development, Interuniversity Research Center for Sustainability (CIRPS), Naples