ARRS 2022 Abstracts

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E2021. Impact of COVID-19 on V/Q Scan: Comparative Analysis of Pre-COVID Era V/Q Scan to the Current COVID Era Perfusion Scan
Authors
  1. Pokhraj Suthar; Rush University Medical Center
  2. Mohammed Alagha; Rush University Medical Center
  3. Sumeet Virmani; Rush University Medical Center
Objective:
Worldwide rapid emergence of the COVID-19 pandemic has altered the practice of medicine. To prevent contamination and spread of COVID-19, nuclear medicine ventilation/perfusion scintigraphy (V/Q) was modified to lung perfusion scintigraphy only. The ventilation portion of the study was completely eliminated, thereby minimizing potential for aerosolization and patient-to-patient cross-contamination related to the use of inhalation system. This study provides a comparative analysis of lung perfusion scans performed during the COVID-19 pandemic to V/Q scans performed during the immediate prior pre-COVID era.

Materials and Methods:
This retrospective study includes comparison of lung perfusion scintigraphy during the COVID-19 pandemic (April 2020 to July 2021, 16 months) to the V/Q scans performed during immediate pre-COVID era (December 2018 to March 2020, 16 months) in a large tertiary care teaching hospital. Ten patients who underwent quantitative lung perfusion were excluded from the study. A total of 511 patients in pre-COVID era and 357 patients in COVID era are included in study. We compared the probability of scintigraphy scans in terms of low, intermediate, and high probability based on modified PIOPED II and perfusion-only modified PIOPED II criteria. Chest radiographs or CT scans performed within 24 hours were used instead of the ventilation scan to correlate the lung perfusion findings during the COVID era.

Results:
As expected, there was 30% decline (154 less lung scans, 357 total) in the overall number of lung scans performed during the COVID-19 pandemic, as compared to the pre-COVID era where 511 V/Q scans were performed. Out of 511 patients who underwent a V/Q scan during pre-COVID era, 349 (68.3%) had low, 142 (27.8%) had intermediate, and 20 (3.9%) had a high probability scan for pulmonary embolism (PE). Out of 347 patients who underwent lung perfusion scintigraphy during COVID era, 199 (57.3%) had low, 114 (32.9%) had indeterminate scans, and 34 (9.8%) had high probability scans for PE. Out of 347 patients in COVID 19 era, 287 underwent either rapid antigen or RT-PCR COVID19 testing; 45 were COVID-19 positive and 243 COVID-19 negative. From 243 COVID-19 negative patients, 143 (58.9%) had low, 75 (30.9%) had intermediate, and 25 (10.3%) had high probability scans. From 45 documented COVID-19 positive patients, 18 (40%) had low, 22 (48.9%) had intermediate, and 5 (11.1%) had high probability scans.

Conclusion:
The perfusion part of the lung scan is sufficient for evaluation of acute PE in most patients. Eliminating the ventilation part of the V/Q scan had only a minimal impact on the interpretation of the study. A 5.1% rise in indeterminate probability or nondiagnostic scans using perfusion-only modified PIOPED II criteria during COVID-19 era is thought to be due to underlying lung parenchymal involvement seen on chest radiographs for most patients who tested positive for COVID-19. Another 5.9% rise in high probability scan as compared to the pre-COVID era is due to known hypercoagulability and vascular complications in patients with COVID-19.