Pulmonary embolism on ventilation/perfusion scintigraphy during the COVID-19 pandemic

ABSTRACT

Aim/Introduction: In March 2020, the World Health Organization (WHO) declared the coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) a pandemic. One complication associated with COVID-19 disease is a thrombotic event, including pulmonary embolism. The most commonly used imaging modality in nuclear medicine for diagnosing pulmonary embolism is ventilation/perfusion singlephoton emission computed tomography (V/Q-SPECT), especially in patients who are contraindicated to iodinated contrast agents and are not suitable for computed tomographic pulmonary angiography (CTPA). However, the true impact of these increased thromboembolic events on pulmonary scintigraphy results has not yet been investigated. Therefore, we investigated the value of ventilation/perfusion scintigraphy for diagnosing pulmonary embolism during the COVID-19 pandemic. Material(s) and Method(s) We retrospectively reviewed medical records of patients examined with 81mKr or 133Xe ventilation/ 99mTc-MAA perfusion scintigraphy between January 2019 and May 2021. Patients only examined with perfusions scintigraphy were excluded. The lung scintigraphy findings before (January 01, 2019 to March 15, 2020) and during (March 16, 2020 to May 31, 2021) the pandemic were compared. The number of examinations performed in the two periods were compared using Poisson regression, whereas Pearson's chisquare test was used for severity parameters. Result(s) The study population contained 1.127 patients, 538 before and 589 during the COVID-19 pandemic. The mean age was 68 years (standard deviation 17, range 17-99 years). No difference in the prevalence of positive lung scintigraphy was found before [144 (27 %)] and during the pandemic [179 (29%)] (p=0.433). During the pandemic the percentage of patients exhibiting central or segmental pulmonary embolisms slightly increased [3 (0.6%) vs. 9 (1.5%) and 21 (3.9%) vs. 29 (4.9%)] compared to before, whereas. subsegmental pulmonary embolisms were equally frequent [120 (22%) vs. 132 (22%)] (overall p=0.345). The number of multiple (>4) emboli was increased [32 (5.9%) vs. 45 (7.6%), p=0.314]. Conclusion(s) During the COVID-19 pandemic, pulmonary ventilation/perfusion scintigraphy is also a reliable examination method for detecting pulmonary emboli. Although increased thromboembolic events were described with COVID-19 infections, no significant increase in the number or severity of detected pulmonary emboli could be observed in our population.