Apr 16, 2020
StatNews.com – To safely relax the chokehold that policies to control Covid-19 have on the economy, most experts agree that the U.S. will need a four-pronged strategy:
- aggressive diagnostic testing for the disease,
- isolation of known cases,
- tracing of their contacts, and
- quarantining of anyone who might have been exposed until they are clearly uninfected.
Many public health officials have focused on the challenge of contact tracing, saying it will require “an army” of new workers.
In fact, however, the re-opening effort is in danger of failing spectacularly because the U.S. hasn’t gotten the first and last steps right — which both rely on accurate diagnostic testing. The current swab tests for the novel coronavirus are missing up to 30% of infected people.
In a scramble to fix that before it’s too late, a growing number of doctors are calling for use of another method to detect Covid-19, one that would miss fewer cases than molecular testing of swabs does: chest CT scans.
CT scans are far more expensive, they expose patients to a low dose of radiation, and the Centers for Disease Control and Prevention and some medical groups recommend against using them to diagnose Covid-19.
But they were widely used in China to identify cases, and their reliability there is fueling growing interest in adding chest CT to the diagnostic arsenal in the U.S.
The scans detect hazy, patchy, “ground glass” white spots in the lung, a telltale sign of Covid-19.
In one recent study of 1,014 patients, published in the journal Radiology, scientists in China reported that chest CT found 97% of Covid-19 infections.
In comparison, the study found that 48% of patients who had negative results on the swab test, which detect the coronavirus’s genome, in fact had the disease.
“Once you’re a couple of days into infection, chest CT scans don’t miss,” said an emergency medicine physician … Read more.