CT scanning is just awful for diagnosing Covid-19

This study, in the same high-tier journal, claims that the sensitivity of CT is 98% vs a sensitivity of 70% for viral PCR. They say: “Our results support the use of chest CT for screening for COVD-19** for patients with clinical and epidemiologic features compatible with COVID-19 infection particularly when RT-PCR testing is negative.” With a statement as strong as that, surely they are saying that they have evidence that CT can be applied broadly? They even mention patients with epidemiological features of infection … that is to say, folks who have been exposed but don’t have symptoms. Here is the patient cohort diagram: We can see we are again looking at only hospitalised patients who underwent CT, so we are likely to be overestimating the sensitivity due to selection bias. But I noticed something else in this paper too – they show us the images for some cases, and some of the images are a bit weird. The image below, which was reported to contain “atypical features of Covid-19” (specifically “small peripheral linear opacities bilaterally”), was a massive red-flag for me. Well, they must be small, because that looks like a normal CT chest  Now, maybe that image was unrepresentative or included by error, but they show this one as well, with a handy arrow: According to this paper, tiny random opacities are now diagnostic of Covid-19. I’m getting snarky here, this is only 2 images out of the dozen or so in the pape...
Source: The Health Care Blog - Category: Consumer Health News Authors: Tags: Artificial Intelligence COVID-19 Health Tech Physicians Research CT Luke Oakden-Rayner Radiology Source Type: blogs