Incidental detection of a lung perfusion defect suspicious of pulmonary embolism on labelled white blood cell quality control imaging—case report

BACKGROUND: Incidental findings could be a very important observation in various nuclear medicine studies. There have been few cases of incidental findings of perfusion abnormalities on early quality control images of the lungs during radiolabeled white blood cell studies. This study is the first to detect perfusion defects on the early quality control images of the lungs during a labelled white blood cell study suspicious of pulmonary embolism in an unknown but treated COVID-19 patient. CASE PRESENTATION: We present a 40-year-old male who was referred to our department for a nuclear medicine (99m)Tc HMPAO-labelled white blood cell study to rule out osteomyelitis of his right foot. Early 5-min quality control images of his lungs revealed two perfusion defects in the right lung. A suspicion of pulmonary embolism was made, and a perfusion only SPECT/CT study the next day confirmed the suspicion of pulmonary embolism in one of the defects, with a possible fissure sign as a differential. CONCLUSION: There has been an increase in the incidence of lung perfusion abnormalities and pulmonary embolism during the COVID-19 pandemic. Some of these may be detected as incidental findings on early lung quality control images of radiolabeled white blood cell studies.