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The Indian Radiological and Imaging Association (IRIA) on Wednesday quashed AIIMS Director Dr Randeep Gulerias claims that one CT Scan was equivalent to 300-400 X-Rays. The IRIA called Dr Gulerias claims unscientific and irresponsible.

Nagpur based radiologist Dr Abhishek Neral shares a detailed rebuttal against the recent claims of CT Scan being harmful and tells why it is the ‘Gold Standard’ in detecting the severity among COVID-19 infected patients.

A CT Scan of the chest gives detailed information on evidence of COVID-19 infection and shows condition of lungs in early stages of the COVID-19 infection. CT Scan (of the chest) helps to identify the severity of the infection in asymptomatic and symptomatic patients.

It helps them decide whether the patient requires home isolation or hospitalisation.
CT Scan helps in identifying whether the infection is mild, moderate or severe; it helps in clinical management and also the progression of disease can be monitored in deteriorating patients. As CT Scan is much more sensitive in detecting lung damage than pulse oximetry, initiating steroid medication can halt lung damage and save lives.

Delay in RT-PCR reports and false negative reporting 

CT Scan gives quick and detailed information of the disease whereas, there are delays in results of RT-PCR reports. Plus, we have observed that there have been a lot of false negative RT-PCR reports, which might be because of inadequate sample collection by the technicians or incapability of laboratory machines. In such cases also, CT Scans give accuracy.‘

Also read: 1 CT scan equivalent to 400 X-rays! AIIMS Chief warns against risk of cancer

A predictive model and scoring system CO-RADS (Corona virus disease 2019 Reporting and Data System) provided by Indian Council of Medical Research (ICMR), provides a CT Severity Score (CTSS 0-25).

Combining both. clinical and CT features are developed to enable high diagnostic efficiency for COVID-19 that helps the physician to decide the line of treatment. Patients can avoid or start with steroids and antiviremia according to the severity of the disease.

1 CT Scan is not equivalent to 400 X-Rays!

The above mentioned statement is absolutely incorrect and outdated. IRIA is of the belief that one CT Scan being equal to the radiation exposure of 300-400 X-Rays is a thing of the past (at least 30-40 years ago). Modern ultra low dose CT Scanners coupled with the advancement in softwares ensures a low dose of chest CT Scan is about 1.5 mSv, which almost equivalent to just two to three chest X-Rays.

It emits radiation, which is not comparable 300-400 X-Rays. IRIA also added that the chest CT Scan helps diagnose symptoms early and prevents them from being super-spreaders. It also compared how quick the chest CT Scan was, as opposed to the RT-PCR, which takes at least a few hours to deliver results. 

Radiologists world over use the ALARA Principle (As Low As Reasonably Achievable) and give the minimal rendition possible during the process. Also, the statement that CT Scan can cause cancer is alarming, as the radiation from a single CT Scan is almost equivalent to the radiation (which one normal person is exposed to without undergoing a scan) received by any person over a year. Moreover, radiology body calls Gulerias remark unscientific and irresponsible.  

COVID-19 suspected and positive patients should not rely on X-Rays     

CT Scans are highly sensitive; they give a detailed view unlike X-Rays, which can only be used for monitoring patients with severe COVID-19 pneumonia. Chest X-Ray provides 2D image while CT Scan provides a 3D image.

X-Ray is built to examine dense tissues where as CT Scan is better able to capture bones, soft tissues, blood vessels, etc. An X-Ray cannot provide the CT severity score, through which reporting for COVID-19 cases are done  something that is approved by ICMR.