Referrals from the Nuclear Medicine department to the Emergency department of our hospital for incidental findings in PET-CT studies in two years of the COVID-19 pandemic

ABSTRACT

Aim/Introduction: PET-CT with diagnostic CT with intravenous administration of iodinated contrast allows increasing the diagnostic efficacy of the studies by combining in a single exploration the anatomical information of CT and the metabolic information of PET. A small percentage of these patients will show incidental findings that require urgent management of the patient, taking into account that most of them are oncologic patients. Otherwise, SARSCoV-2 has caused the coronavirus disease 2019 (COVID-19) throughout the world turning into a public health emergency. PET-CT studies of some asymptomatic cancer patients showed lung involvement suggestive of COVID-19 pneumonia. Our aim is to retrospectively analyze patients who required urgent medical attention when they attended for a PET-CT scan during the years 2020 and 2021. Material(s) and Method(s) We did a retrospective review of the reports of 9057 PET-CT scans performed in our hospital during the years 2020 and 2021 (8884 with18F-FDG, 5068Ga-DOTATOC, 10618F-Fluorocholine, 1418F-DCFPyL and 318F-FDOPA). From those, 8499 (93,8%) were oncologic patients. Patients who were referred to the Emergency Department from Nuclear Medicine due to hyperglycemia or incidental findings in the PET-CT scan requiring urgent medical attention were selected. The studies were acquired after intravenous injection of radiotracer, in a PET-CT camera (multidetector CT). Most studies were performed with intravenous (i.v.) iodinated contrast, acquiring a chest sequence in inspiration and arterial phase and another full body sequence in portal phase. Each study was evaluated by an expert nuclear medicine physician and a radiologist. A single report was subsequently drawn up. Result(s) 143 patients (1.57%) with an incidental finding requiring urgent attention were identified. Twelve of these patients (8,39%) were referred to the Emergency Department for the presence of hyperglycemia greater than 350mg/dl so that PET-CT scan could not be performed. The most frequent incidental findings in PETCT images were pulmonary thromboembolism (34 patients;23.8%), venous thrombosis (25;17.5%) and pulmonary infiltrates suggestive of COVID 19 disease (15;10.5%). The most frequent pathologies among the patients studied were lung cancer (30 patients), breast cancer (28 patients) and head and neck cancers (15 patients). Conclusion(s) PET-CT has proven to be useful in the incidental finding of medical pathologies that require urgent medical attention. Likewise, the performance of a directed chest CT with iodinated contrast within the PET-CT protocol has contributed to the diagnosis of pulmonary thromboembolism, a relatively frequent finding in oncologic patients.