299 [18F]FDG-PET/CT to prevent futile surgery: a blinded, randomised controlled multicentre trial 4 Procedures All patients underwent an [18F]FDG-PET/CT of the neck, acquired by 20 PET/CT scanners at 12 EARL-accredited study sites (Table 1) using a standard acquisition and reconstruction protocol in accordance with European Association of Nuclear Medicine (EANM) guidelines [468, 469]. In summary, patients fasted for at least six hours prior to the injection of the radiopharmaceutical (activity adjusted for patient body weight, time per bed position and PET/CT scanner sensitivity). Approximately 60 minutes (range 55-70 minutes) after intravenous [18F]FDG administration, patients were scanned from the external acoustic meatus to the aortic arch in supine position, with at least two minutes per bed position. A low-dose non-contrast enhanced CT scan was performed. EARLreconstructed, pseudonymized scans were stored in a central, password-protected online database within the National Biomedical Imaging Archive environment (NBIA, National Cancer Institute, Bethesda, MD, USA). Next, scans were centrally assessed by two independent, experienced nuclear medicine physicians (LG and DV). Any focal [18F]FDG-uptake within the thyroid that was visually higher than the background [18F]FDG-uptake of the surrounding normal thyroid tissue and that corresponded to the index thyroid nodule in size and location, was considered positive. To support the visual assessment, [18F]FDG-uptake was quantified using maximum and peak (ø1-cm sphere) standardised uptake values (SUVmax, SUVpeak), using body weight for normalization. In case of a discordant assessment, a third reviewer (WO) was consulted for a consensus meeting. All image analyses were performed using OsiriX Lite DICOM-viewer (Pixmeo SARL, Bernex, Switzerland). One project team member (EK) combined patient allocation and the [18F]FDG-PET/CT result to a preformulated treatment advice. A written report containing only this advice was presented to the patient’s local physician; the patient’s allocation and [18F]FDG-PET/CT result remained concealed. If present, incidental [18F]FDG-PET/CT-findings outside the index nodule and with potential diagnostic and/or therapeutic consequences were also reported in an appendix to the report, to be evaluated by the local physician in the context of the patients’ medical history. In the [18F]FDG-PET/CT-driven group, the treatment advice was based on the [18F]FDG-PET/CT results. When the index nodule was [18F]FDG-positive, patients were advised to proceed to the scheduled diagnostic surgery. When the nodule was [18F]FDG-negative, patients were advised to refrain from surgery and undergo active surveillance of the nodule, which was defined as at least one follow-up ultrasound exam of the neck and outpatient clinic visit after one year. Any additional follow-up visits during study participation were permitted at the discretion of the local physician. The nodule was presumed benign when it remained unchanged in size and appearance on the one-year ultrasound. In case of significant growth (>50% volume change or >20% increase in at least two dimensions, excluding cystic components) or changed ultrasound appearance including newly observed suspicious characteristics, further evaluation by repeat FNAC was recommended. Suspicious ultrasound characteristics were defined as a marked hypoechoic solid
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