key: cord-0865823-oafn5y8v authors: Gayed, Isis W.; Browne, Alexandra; Kaur, Harleen title: Perfusion Lung Scans During the Pandemic: COVID-19 Experience in a Large Trauma Hospital date: 2022-05-25 journal: nan DOI: 10.1016/j.jrras.2022.05.004 sha: bba6a74f620ca74b4591d1ba4d4c6375228c2ab7 doc_id: 865823 cord_uid: oafn5y8v PURPOSE To evaluate the results of perfusion only lung scans and the frequency of necessary addition of the ventilation part of the scans to diagnose acute pulmonary embolism (PE) during Corona Virus Disease of 2019 (COVID 19) pandemic. MATERIAL AND METHODS We retrospectively reviewed perfusion lung scans’ results between April to December, 2020. The images were interpreted by two experienced nuclear medicine physicians as daily routine studies. Ventilation images were performed only if deemed necessary for accurate diagnosis of acute PE. RESULTS A total of 128 lung perfusion scans in 127 patients were included. The scans were interpreted with certainty using the modified PIOPID criteria in 122 patients (95.3%). The results included low probability for acute PE in 110 patients (85.9%), normal in 6 patients (4.7%) and high probability of acute PE in 6 patients (4.7%). Ventilation imaging were performed in 4 patients with high probability, after negative testing for COVID19. The other 2 high probability results were confirmed clinically and with radiologic imaging. Only 6 scans (4.7%) were interpreted as intermediate perfusion scans, two of which due to inability to differentiate old from new perfusion defects in patients with chronic thromboembolic disease. Thus, the true indeterminate results due to the lack of ventilation scan were encountered in only 4 intermediate probability lung scans (3.1%). Thus, the total number of requested ventilation scans was 8 scans (6.2%) when considering both the high and intermediate probability interpretations. Six scans were performed (2 in the intermediate and 4 in the high probability scans). The two ventilation scans performed in the intermediate probability changed the diagnosis to low probability and the four performed in the high probability confirmed the initial interpretation of high probability scans by perfusion only. CONCLUSION The ventilation part of lung scans is required only in a small number of patients for certain interpretation of the result. Perfusion lung scans are sufficient for evaluation of acute PE with certainty in most patients. A Surely, this was the most difficult time when many patients are presenting with shortness of breath and there was a desperate need to differentiate those suffering from COVID 19 only, acute PE or both for appropriate management of those patients. Many institutions including our large trauma hospital opted to performing perfusion only lung scans as per the recommendations of the SNMMI statement with ventilation scans performed only when necessary to ensure accurate diagnosis of acute PE. Our observation during the period of the pandemic that we rarely needed ventilation scans to confirm or rule out the diagnosis of acute PE. Therefore, we systematically evaluated and J o u r n a l P r e -p r o o f reviewed the results of our perfusion first lung scans and how it impacted our interpretations of lung scans and the patients' final diagnosis during the pandemic period. After obtaining our institution review board approval, we retrospectively collected data from all consecutive lung scans performed between April and December 2020 during the peak of the pandemic period in the USA. During this period, we performed perfusion lung scans first followed by ventilation scan only if the patient tested negative for COVID 19 and the ventilation part of the study was deemed necessary by the interpreting nuclear medicine physician when segmental or subsegmental perfusion defects were seen on the perfusion scan. Perfusion planar images in the Descriptive statistics was used to analyze the collected data and evaluate the results. This included calculation of means, medians and percentages. A total of 128 lung perfusion scans in 127 patients were performed at our institution, including 68 female and 59 male patients with average age of 61 yr. Perfusion scans were performed for 99 inpatients, 25 outpatients and 3 emergency room patients. The indications were variable and are summarized in Table 1 . The interpretation results included low probability for acute PE in 110 perfusion scans (85.9%), normal in 6 scans (4.7%), intermediate probability in 6 scans (4.7) and high probability of acute PE in 6 scans (4.7%) (Fig.1) . The scans were interpreted with certainty in 122 perfusion only scans out of 128 total perfusion scans (95.3%). These included the scans interpreted as normal (6), low (110) and high probability (6) four patients, underwent a ventilation scan following the perfusion scan and confirmed the high probability for acute PE (Fig. 2) . One patient had a clear change of his perfusion lung scan in onemonth interval which confirm the incidence of acute PE (Fig. 3) . The remaining patient with high probability interpretation was confirmed with pulmonary CTA and clinical suspicion. Thus, a total The results of our study indicate that ventilation scans are needed in a small percentage (6.2%) of all lung scans to confirm the diagnosis of acute PE. Despite the fact that a change of our imaging protocol to perfusion only lung scans and ventilation when needed was a necessary change during the pandemic, it was also an eye opener to a possible permanent and more practical approach to lung imaging for acute PE in the field of nuclear medicine. This can become a permanent change in lung imaging and would be beneficial and welcomed in the field to facilitate easier and faster diagnosis of acute PE. It would also be less demanding for the patients who are frequently short of breath and have difficulty in complying with the ventilation part of the study. Additionally, it would also be welcomed in many institutions to decrease the demand on performing pulmonary Robinson, 1996) . In the high probability scans, the segmental pattern of the perfusion defects was convincing of the presence of acute PE (Fig. 1) Limitations of our study is the retrospective nature of the study with less control on the variables of the study. However, our study is a good reflection of the daily routine performance of perfusion only lung scans during the pandemic time. We consider it as an unexpected opportunity for evaluation of perfusion first lung scintigraphy on a daily routine basis. Another limitation is the lack of assessment of interobserver or intra-observer agreement for the interpretation of the scans which is an inherent deficiency in the retrospective nature of this study. However, we consider the large number of patients evaluated in this study during the pandemic is a strength of our study. Additionally, the fact that we continued to perform lung scintigraphy during the pandemic time was an important contribution to patient management during this precedent time. We have also contributed to the care of COVID 19 patients who are at increased Pneumonia of unknown cause -China. WHO website Unity studies: Early investigation protocols. WHO website Mapping Covid-19 SNMMI statement: Covid-19 and ventilation/perfusion (V/Q) lung studies. SNMMI Acute pulmonary embolism: Sensitivity and specificity of ventilation-perfusion scintigraphy in PIOPED II study Acute pulmonary embolism: Sensitivity and specificity of ventilation-perfusion scintigraphy in PIOPED II study 2014 ESC guidelines on the diagnosis and management of Acute Pulmonary embolism The feasibility of performing 133XE ventilation imaging following the perfusion study Enhancement of Xe-133 ventilation lung scan image acquired after Tc-99m perfusion scan The accuracy of V/Q SPECT in the diagnosis of pulmonary embolism: A meta-analysis EANM guidelines for ventilation/perfusion scintigraphy: part 1. Pulmonary imaging with ventilation/ perfusion single photon emission tomography Clinicians' interpretation of the indeterminate ventilation-perfusion scan report A decision analysis approach to the treatment of patients with suspected pulmonary emboli and an intermediate probability lung scan Predictors of an intermediate ventilation/perfusion lung scan in patients with suspected acute pulmonary embolism Computed tomography scan versus ventilation-perfusion lung scan in the detection of pulmonary embolism Imaging of acute pulmonary thromboembolism: should spiral computed tomography replace the ventilation-perfusion scan? Ventilation-perfusion lung scanning and spiral computed tomography of the lungs: competing or complementary modalities? Systematic review and meta-analysis of strategies for the diagnosis of suspected pulmonary embolism Ventilationperfusion lung scanning and the diagnosis of pulmonary embolism: improvement of observer agreement by the use of a lung segment reference chart The use of Xenon-133 ventilation scan performed immediately after Tc-99m MAA perfusion scan Pulmonary embolism in patients with covid-19 pneumonia Lille ICU Haemostasis COVID-19 Group Pulmonary Embolism in Patients With COVID-19: Awareness of an Increased Prevalence Pulmonary embolism and deep vein thrombosis in covid-19: A systematic review and meta-analysis Pulmonary embolism in patients with COVID-19 pneumonia: When we have to search for it