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‘Avoid CT scan for Covid diagnosis’

DGHS urges physicians not to conduct it for asymptomatic, mild cases

By M. Sai Gopal

Updated On - 8 June 2021, 12:36 AM

‘Avoid CT scan for Covid diagnosis’ — During the ongoing pandemic, the chest CT scan has been the most exploited diagnostic test prescribed by physicians.

Hyderabad: The Director General of Health Services (DGHS), MOHFW, New Delhi has advised physicians involved in treatment of Covid-19 patients to avoid prescribing frequent High-Resolution CT (HRCT) scan of the chest. The DGHS made it clear that the CT chest scan should not be conducted for asymptomatic and mild Covid-19 cases.

During the ongoing second wave and even during last year’s pandemic, the chest CT scan has been the most exploited diagnostic test prescribed by physicians. While government doctors at teaching hospitals in Telangana avoided prescribing such tests, private healthcare establishments conducted the chest scan on Covid patients frequently, irrespective of the degree of infection. To curtail unnecessary application of HRCT scan of the chest, the DGHS in a clearly worded recent advisory on clinical management of Covid-19 positive patients said that the “treating physicians should exercise caution while advising HRCT imaging of the chest.”

The HRCT scan of the chest provides better visualisation of the extent and nature of lung involvement in patients with Covid-19. However, any such additional information gained from HRCT scan of the chest often has little impact on treatment decisions. At present, treatment decisions are based almost entirely on clinical severity and physiological impairment. Therefore, treating physicians should be highly selective in ordering HRCT imaging of Chest in patients of Covid-19, MOHFW advised.

The DGHS has in its advisory said that routine HRTC imaging of the chest must be avoided because nearly two-thirds (66 per cent) of persons with asymptomatic Covid-19 have abnormalities on HRCT chest imaging which are nonspecific and most of them do not progress clinically. “HRCT imaging of the chest done in the first week of illness might often underestimate the extent of lung involvement, giving a false sense of security. Correlation between extent of lung involvement by HRCT imaging of chest and hypoxia is imperfect. Often, young individuals with extensive lung involvement will not develop hypoxia, while elderly individuals with minimal/ less extensive lung involvement are likely to develop hypoxia,” the DGHS made it clear.

The DGHS also pointed out the ill-effects of getting exposed to radiation due to repeated HRCT imaging, which is often linked to the risk of cancer later in life. “CT scan of the chest should not be done for the purpose of diagnosing or screening Covid-19 infection. The Covid diagnosis must be done only by using appropriate laboratory tests like RT-PR, which are recommended by Indian Council of Medical Research,” the DGHS in its advisory said.