HRCT: An efficient primary diagnostic test for COVID-19 pneumonia – An Indian perspective
RT-PCR has been the testing protocol for diagnosis of COVID-19; shortcomings include limited availability, long turn-around times, and false-negative reports indicating that sensitivity remains around 70%. Previous researchers have shown that the false-negative ratio of RT-PCR test for patients infected with COVID-19 is approximately 1 in 5. HRCT has been widely accepted for prognostication of COVID-19 pneumonia. Tests were conducted on people who were either index cases who had been recently diagnosed for COVID-19 or patients whose testing was performed and results awaited but were clinically symptomatic. HRCT was deemed “positive” for diagnosis of COVID-19 pneumonia if either one or a combination of several well-described signs were seen—including but not limited to ground-glass opacities in typical peripheral sub pleural distribution, sub pleural/interlobular interstitial thickening, atoll sign, halo and reverse halo signs, to name a few. Further, CT severity index was evaluated for the patients who had a “positive” HRCT to assess the severity in these patients.
In places where the prevalence of pandemic is high, a fast, non-invasive, accurate, and inexpensive test for screening and diagnosis is essential. The sensitivity of HRCT, when compared with RT-PCR, has been previously studied and was shown to be higher than RT-PCR. This study has proven that HRCT is a very useful tool for the initial diagnosis of patients suspected to have COVID-19 irrespective of symptoms or day of onset of CT. Considering the many overall advantages, HRCT for the chest deserves to be included in the official diagnostic guidelines for diagnosis.