Implementing CT as front-line tool for COVID-19 diagnosis requires 'urgent discussion,' radiologists say

As the coronavirus continues to tear across Europe and into the U.S., one group of U.K.-based radiologists is wondering if computed tomography chest imaging should take on an expanded role in assessing patients.

“Early diagnosis is absolutely critical to containment,” Samanjit S. Hare, a consultant chest radiologist with Royal Free London National Health Services Foundation Trust, and colleagues wrote in a recent editorial. “Radiology services have found themselves at the center of a debate on how to approach diagnosis of this novel coronavirus.”

The four physician authors—all members of the British Society of Thoracic Imaging—noted that while RT-polymerase chain reaction test kits remain sufficiently available in the UK, and labs can manage the increase in demand, CT scanning only has a “limited role” in diagnosing COVID-19. In the U.S., sluggish rollout and limited availability has hampered widespread testing, the New York Times reported.

But if these labs continue to experience 24- to 48-hour delays, or testing becomes unavailable, the experts believe “the implementation of CT imaging as a frontline diagnostic tool, as rolled-out in China, requires urgent discussion.”

Those who would push for this approach, Hare et al. noted, might draw on conclusions from a Feb. 26 study of more than 1,000 patients in Hubei who received both chest CT and lab testing. In those with an initially negative RT-PCR, but positive CT scans, 81% were reclassified as “highly likely” or “probable” to have the virus. And overall, the modality’s sensitivity was 97% compared to positive RT-PCR.

Even so, the researchers cautioned against being overly reliant on positive chest CTs, given that imaging changes from the new virus might only appear gradually.

Hare and colleagues also noted that without proper planning and infrastructure for large-scale CT imaging, these machines face potential widespread contamination. They suggested hospitals use mobile scanners and designate them as either clean or dirty, with the latter reserved for examining suspected COVID-19 cases.

“Undoubtedly, such measures would have massive consequences for staffing and routine hospital workloads,” the editorialists wrote March 12 in the BMJ.

The American College of Radiology warned of a similar impact to patient care in a statement issued Wednesday. The college also suggested that hospitals should not use CT as a first-line tool to diagnose the new virus.

The real problem is not rooted in the coronavirus pandemic, but rather a long-term lack of investment into radiology services, the BMJ authors argued. A shortage of both CT scanning machines and radiologists themselves will be the true challenge in containing this new virus, they wrote.

“In spite of limitations, radiology departments around the country remain ready as ever to answer the call and must actively prepare to deal with the COVID-19 crisis, a disease for which imaging appears to play an emerging role,” the group concluded. “A provision for more CT access—possibly with mobile CT scanners—may be a step in the right direction.”