What CORADS and the CT Covid Score teach us

Structured reporting became extensively used worldwide over the last decade, as it improved reporting clarity and patient care. And yet, its acceptance in India was not as widespread and rapid as it ought to have been. Even BIRADS, PIRADS and LIRADS were not often used still. Some radiologists found it unnecessary as their free text reports ‘always covered all details’ anyway. Others felt writing a structured report took too long. Many believed that it limited the ‘art of reporting’. Few simply had too much inertia.

And then came Covid. Almost overnight, every radiologist (including those who disliked structured reports) started giving not one but two discrete standardized terminologies – CORADS and the CT Covid score. CORADS communicated the certainty of the Covid diagnosis, while the CT score conveyed the extent of lung involvement. Interestingly, CORADS and the CT Covid score were not widely adopted internationally, nor recommended by international societies. This standardization evolved organically within India itself, and at a breakneck speed. Indeed, academic radiologists who long championed the cause of structured reporting were left scratching their heads about the origin and reasons why this succeeded compared to other better established RADS! Perhaps it was because the lockdown gave many the time to read Covid-related radiology literature and then sit down and create a template which they felt would help. And the clinical impact of the template along with a bit of FOMO then helped spread the use.

As we now look back, few things are clear.

First, the adoption was radiologist-driven; we started providing CORADS rather than the physicians demanding it first.

Secondly and more importantly, the standardized reports had an enormous impact. During the 1st and 2nd waves, RT-PCR had limitations due to lack of availability and long turnaround times. This led to hospitals keeping suspect patients in ‘holding areas/triage zones’ till the RT-PCR results came back. Most hospitals however allowed admitting patients with a CORADS 5 CT report into the Covid ward/ICU, even if the RT-PCR result was not yet out. The MCGM (Municipal Corporation of Greater Mumbai) permitted this as well. Would everyone have allowed a ‘Covid needs to be ruled out’ or ‘Covid needs to be considered’ or ‘findings consistent with infectious etiology, probably Covid’ report? I am not too sure. There is just too much variability in our language in such free text impressions, making the certainty of our impression unclear to the reader. CORADS undeniably enabled doctors to overcome hospital bureaucracy and provide timely treatment to innumerable Covid patients. The CT Covid score also had a somewhat unexpectedly huge impact. Many doctors in fact used its value to decide on which patient needs hospital admission or steroid administration.

And the third and interesting take-home point is that using structure and lexicon clearly did not slow down reporting. I know so many who used to report over 50 CT chests during the second wave without breaking a sweat. If anything, it made reports faster and more specific!

The lessons are there for all to see. Covid has washed away all old arguments against structured reporting. Using a standard template and lexicon allowed everyone be on the same page regarding what is being reported. If a patient had a low CT score, the GP could treat symptomatically. If high, s/he could immediately teleconsult a specialist and get appropriate advice. This happened without the physician needing to call the radiologist for any clarification, and irrespective of whether the CT was reported by a someone with one year of experience or 21 years of experience. This was key to why CT succeeded in guiding management in India despite lack of evidence or international guidelines. To make the circle complete, the impact of CORADS and the Covid score made CT pretty much standard in most Covid patients during the second wave, driving up CT volumes as well. In short, standardized Covid CT reports helped not just the referring doctors and patients but radiologists as well! If this first-hand experience on the positive impact of structured reporting for all stakeholders doesn’t drive us to start using structured templates for other pathologies, what will? Seeing is believing after all. Let’s hope this adoption happens in 2022!

We can actually take the lessons a step further and innovate with more India-specific templates. For example, the biggest killer infection in India which truly needs imaging for diagnosis and management is not Covid, but TB. TB treatment is often started on the basis of the radiology report. The ACR is really not the body which will introduce a TB-RADS lexicon. It is we Indian radiologists who need to take a cue from our Covid experience and develop something like that. You sure it’s active TB? Call it TB-RADS 5. Not sure about TB vs some other infection? Call it TB-RADS 3. You feel it is only TB sequela and not active TB; introduce a dedicated term in the RADS for that (TB-RADS Seq or TB-RADS 2S); this will save so much headache for thousands applying for a job in India and abroad. We can define specific descriptors and findings which help classify an X-ray or CT as TB-RADS 4 vs 5. I am sure other India-specific pathologies are also ripe for introducing similar lexicon.

But we should not stop there either. The actual fact is that most Covid management in India (including the rampant CT use and the polypharmacy) was a combination of ‘experience’-based, ‘gut-feeling’ based and ‘what’s-the-harm’ based medicine; evidence-based medicine had pretty much gone for a toss. For example, despite the widespread use of CT score for Covid management, we still don’t know whether this was actually beneficial to the patients. For example, as per national and international guidelines, steroids should be started in Covid patients only once they develop hypoxia. Starting them early in mild Covid patients actually worsens outcomes, as steroids suppress the patient’s immunity. Given these facts, the logical question to ask is whether there is a subset of patients who are not hypoxic but have moderate lung involvement on CT who will benefit from steroids, or is even this practice harmful? If beneficial, at what cut-off are steorids useful – 12 or 15 or 18? Unfortunately, no trial was designed in India to answer this very important question. Moreover, the fact is that most experts both in India and abroad believe that the CT score should not be used to start steroids. But without trials, we cannot prove or disprove them. We simply must acknowledge this missed opportunity. Despite the widespread use of CT, we published barely a handful of papers on CT and Covid in high impact factor international journals (compare this with the number of papers published from say China in Radiology!). I am sure the Indian medical community can act with more scientific temperament than this in the future.

Since it’s the new year, let us have all of this on our 2022 wishlist – that we not only widely adopt established structured templates, but also work with scientific rigour to create, validate and adopt India-specific lexicon, thus positively impacting patient care. If we have truly learnt our lessons from our Covid experience, I am sure we can do this!

– Akshay Baheti (views are personal)

2 thoughts on “What CORADS and the CT Covid Score teach us

    1. The Rad wars have begun!!!
      Any specific reason for stating so? Agree that it should not really be a race, and that Rads should be introduced when needed. The broader point of the article is the need to have more structured reporting and the impact they have; using Rads is only a small part of the process.


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