Originally published February 10, 2021
In March and September 2020, SNMMI released a statement to address concerns about the inherent risk of COVID-19 spread to patients and staff related to the ventilation portion of ventilation perfusion (V/Q) scans. Understanding the importance of the complete V/Q study to accurate diagnoses, SNMMI has since updated their statement to emphasize the increasing safety in performing lung ventilation scans.
In the spring of 2020, as the virus spread rapidly throughout the U.S., the infection risk to healthcare workers and patients became a serious concern. While information about the virus and its transmission was limited, SNMMI issued a safety statement that included a recommendation to eliminate the ventilation portion of standard V/Q studies until more was known about the risks. Some institutions chose to follow this recommendation despite the loss of important information about airway physiology.
At the time of SNMMI’s initial statement, COVID-19 testing and access to personal protective equipment (PPE) was limited, vaccines were not yet available, and it was believed following a perfusion-only V/Q protocol would be safer in the short term. If the perfusion images showed no abnormalities, there was a high degree of confidence that there were no pulmonary emoli present. However, perfusion-only scans removed significant information needed to accurately diagnose this population.
SNMMI Updates Safety Statement on V/Q Scans
In September 2020, SNMMI issued their first update to the original safety statement. Recognizing the potential risks of anticoagulation in this population and the importance of diagnostic accuracy, SNMMI stated that there are cases where perfusion-only images are not definitive and a ventilation study is needed.
“[V]entilation images provide important information about airway patency and obstructive lung disease that may help to explain symptoms,” the statement reads.
SNMMI added that while uncertainties remained about potential COVID-19 transmission through the use of ventilation systems, a ventilation study may be performed when deemed medically appropriate provided adequate access to COVID-19 testing and other safety measures are in place.
Increasing Safety in Ventilation Studies
Citing the active and widespread distribution of vaccines and increased testing availability as signicant developments regarding COVID-19 since the September 2020 statement, SNMMI issued a second update to their safety statement in March 2021. “SNMMI believes that ventilation scans can be increasingly incorporated as a routine part of the work-up of suspected pulmonary embolism,” the statement reads.
Stressing that local and institutional COVID-19 policies for these types of procedures should be the primary source of guidance, SNMMI issued these six safety items to consider prior to ventilation studies:
- Patients should have documentation of a negative COVID-19 test.
- Technologists should wear appropriate PPE, per local policies.
- Airflow in the room in which the ventilation studies are performed should be evaluated.
- The selection of the appropriate agent for a veltilation agents should be considered.
- Local infection control groups should be engaged for guidance and to help evaluate facilities.
- The approach to performing a ventilation scan in relation to a perfusion scan should be considered on a case-by-case basis.
Full details on these recommendations can be found on SNMMI’s website.
Growing Support for V/Q Scans as Critical for Patients
By now, many medical institutions have safety precautions in place to help them provide proper care to patients while limiting risk of viral transmission. While the pandemic has posed challenges to the practice of ventilation scans,there are numerous cases where the benefits outweigh the risk.
Studies have shown V/Q scintigraphy to be preferred over CT angiography for potentially fatal chronic thromboembolic pulmonary hypertension. Clinicians have also considered the possibility of long-lasting pulmonary fibrotic damage as well as the component of post-thrombotic sequelae in post-COVID patients.
For COVID survivors in particular, proper analysis of lung health may prove to be critical. One article calls for imaging departments and nuclear medicine to be supported to adapt and manage these risks in order to provide optimal care to COVID-19 survivors:
“[I]nternational guidance on the aerosol-generating potential of radio-nebulisers varies and uncertainties remain, but risks can be safely managed in the post-COVID-19 cohort.”
When You’re Ready, Source for Lung Ventilation Supplies
While regional health care facility policies and guidelines should always govern safety in patient care relating to COVID-19, recent literature and recommendations suggest that complete V/Q scans not only a viable imaging practice. They are at times essential to life-saving diagnoses, and are becoming increasingly safer to perform, as SNMMI attests.
If you are currently performing lung ventilation studies, or are beginning to resume these scans using the recommended safety guidelines, Biodex is ready to assist with cost-saving purchase options for lung ventilation systems and accessories. Please contact Biodex for more information.
Manager, Content Strategy
SNMMI.org. COVID-19 and Ventilation/Perfusion (V/Q) Lung Studies. March 19, 2020.
SNMMI.org. Updated Statement: COVID-19 and Ventilation/Perfusion (V/Q) Lung Studies. September 3, 2020
J. Anthony Parker, MD, PhD, and Kevin J. Donohoe, MD. Lung Scintigraphy in the Era of COVID-19 and Chronic Thromboembolic Pulmonary Hypertension. SNMMI Uptake. May 2020.
Ranju T. Dhawan, et al. Beyond the clot: perfusion imaging of the pulmonary vasculature after COVID-19. The Lancet Respiratory Medicine. Available online 17 November 2020.