Recent literature in radiology suggests that CT scanners may play an important role in the diagnosis of COVID-19.
In a recent article published in The Lancet, a team of researchers has observed that almost all of the confirmed COVID-19 cases under their care also had CT findings of pneumonia.
These medical researchers, working with coronavirus patients in Wuhan, China, have found that 97% of their 1,014 patients with RT-PCR-confirmed diagnoses also had observed lung opacities on CT— a notable manifestation of pneumonia. In their report, the medical researchers have concluded that “CT imaging has high sensitivity for diagnosis of COVID-19”.
This is particularly welcome news, especially with shortages of real-time RT-PCR (reverse transcription-polymerase chain reaction), so far one of the most effective and accurate laboratory methods for detecting, tracking, and studying the coronavirus.
Further Investigation Needed
Meanwhile, another group of researchers has had less optimistic observations.
A team that had reviewed the CT scans of 112 cases of RT-PCR-confirmed COVID-19 from the Diamond Princess cruise ship reported that only 61%– or less than two-thirds– of cases exhibited pneumonia. Furthermore, 20% of symptomatic patients had negative CTs.
So while CT scans do show promise in the diagnosis of COVID-19, these results should not be overstated, cautioned The Lancet.
“The CT findings studied (e.g., ground-glass opacity, consolidation, etc.) are not specific for COVID-19. Similar results would probably be found if CT were used during an influenza epidemic, for example.”
Bringing A.I. Into The Picture
Meanwhile, a medical devices company based in Huizhou, China is exploring the possibility of using an AI-powered imaging solution to aid in the detection of COVID-19
Huiying Medical, a member of Intel’s AI Builders program, claims to have developed the solution’s underpinning algorithms based on data from CT chest scans from over 4,000 coronavirus cases.
Huiying’s solution analyzes what’s known as ground-glass opacity (GGO) in the lungs, which indicates a partial filling of air spaces, as well as other indicators that inform a probability of suspected COVID-19 infection.
Huiying asserts that its solution should be useful in regions of the world without access to real-time RT-PCR. It only takes a day to install and only 2-3 seconds to process CT studies with 500 images.
Moreover, it has a claimed 96% novel coronavirus pneumonia (NCP) classification rate, and it’s designed to work either in the cloud or on-premises.
Through a partnership with Huawei, Huiying has already reached out to many other health professionals and institutions. The new AI-enabled imaging solution is now being used in over 20 hospitals, including those in Ecuador and in the Philippines.
Promising, But Needs More Work
The Lancet stresses that, despite its limitations, RT-PCR is still the accepted standard and only positive in patients who are infected with severe acute respiratory syndrome coronavirus 2.
While advancements in CT technology and research shows promise, the medical journal cautions using published guidelines regarding the use of CT imaging– at least for now.
CT findings in patients with COVID-19 are seen with numerous pathogens and in many non-infectious aetiologies. “Using CT diagnostically is not known to provide clinical benefit and could lead to false security if results are negative,” warns Michael Hope of The Lancet.
“If COVID-19 is suspected, patients should be isolated pending confirmation with (multiple) RT-PCR tests,” he stressed, “or until quarantine has lapsed. The results of a CT scan do not change this.”
Recommendations From The CDC and the ACR
Currently, the Center for Disease Control (CDC) does not currently recommend CXR (chest radiographs) or CT to diagnose COVID-19.
The American College of Radiology (ACR) has its own supporting recommendations for the use of computed tomography (CT) and chest radiography for suspected COVID-19 infections.
Even if radiologic findings are suggestive of COVID-19 on CT, confirmation with the viral test is still required. As such, viral testing remains the only specific method of diagnosis.
In the meantime, until more widespread COVID-19 testing is available, some medical practices are requesting chest CT to inform decisions on whether to test a patient for COVID-19, admit a patient or provide other treatment as an interim measure.
As such, facilities may consider deploying portable radiography units in ambulatory care facilities for use when CXRs are considered medically necessary. The surfaces of these machines can be easily cleaned, avoiding the need to bring patients into radiography rooms.
While locally constrained resources may be a factor in decision making, a normal CT should not dissuade a patient from being quarantined or provided other clinically indicated treatment when otherwise medically appropriate.
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For details and more information about our mobile CT scanners, give our Catalina Imaging team a call today at (844) 949-1664.
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