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.