Nuclear Medicine Blog

In March 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 updated that statement with recommendations for performing lung ventilation scans safely.

In the spring, 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 statement¹ 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.²

At the time of SNMMI’s initial statement, COVID-19 testing and access to personal protective equipment (PPE) was limited, 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.² 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 an update³ to their 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 goes on to say that while uncertainties remain 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.

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:

1. Patients should have documentation of a negative COVID-19 test.
2. Technologists should wear appropriate PPE, per local policies.
3. Airflow in the room in which the ventilation studies are performed should be evaluated.
4. The availability and feasibility of administering ventilation agents should be considered.
5. Local infection control groups should be engaged for guidance and to help evaluate facilities.
6. 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, the benefits may outweigh the risk.

Studies have shown V/Q scintigraphy to be preferred over CT angiography for potentially fatal chronic thromboembolic pulmonary hypertension.² 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 the COVID survivors, 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 survivors⁴:

“[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 are a viable and potentially life-saving imaging practice, and may be performed safely with precautions in place.

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.

¹ SNMMI.org. COVID-19 and Ventilation/Perfusion (V/Q) Lung Studies. March 19, 2020.
² 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.
³ SNMMI.org. Updated Statement: COVID-19 and Ventilation/Perfusion (V/Q) Lung Studies. September 3, 2020.
⁴ 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.

Author:

	Stephanie Viola   Manager, Content Strategy