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Letter to the Editor: “CT and COVID-19: Chinese experience and recommendations concerning detection, staging and follow-up”

by Ercan Kocakoç (ercankocakoc@yahoo.com)

CT and COVID-19: Chinese experience and recommendations concerning detection, staging and follow-up

Dear Editor,

I read the recent recent European Radiology article “CT and COVID-19: Chinese experience and recommendations concerning detection, staging and follow-up.” with great interest [1]. I fully agree with the authors for using CT for diagnosis of possible Covid-19 cases; in spite of some contrary statement and meta-analysis [2-4]. In one meta-analysis authors suggested that chest CT should not be used as a screening test for coronavirus disease 2019 (COVID-19) in countries where the disease prevalence is low due to low positive predictive value of CT examination [2]. This statement might be true at the initial stage of the pandemic where most COVID-19 cases were in China. However, the virus rapidly caused global pandemic affecting 585 individuals per million world population as of May 15th 2020 [5]. The prevalence is much higher in some countries such as Spain (% 0.58) and USA (% 0.44) [5]. Delayed diagnosis and incomplete isolation likely lead to higher transmission and mortality rates.

In our country, early CT is preferred in patients suspected to have Covid-19 suggesting symptoms i.e. fever, dry cough etc. First Reverse Transcriptase-Polymerase Chain Reaction test (RT-PCR test) results are negative in many of the patients (about 40% percent of patients; unpublished data).  However, chest CT usually shows bilateral multifocal and multilobar peripheral ground glass opacity suggesting COVID-19 infections. Patients with starting early supportive treatment is found to have a better outcome and shorter hospital stay than patients with started late treatment on the basis of early experience in Turkey. In early phase, chest radiography usually is normal and chest CT is required for detecting minimal and early findings such as peripheral ground glass opacities or crazy-paving pattern on middle phase of the disease. Early employment of chest CT is one of the important measures keeping the case fatality rate relatively low in Turkey (2.8%) compared to 6.7% global mortality [5].

I am aware of professional organization guidelines against using CT as a “screening” test for Covid-19 [3, 4]. However, given the high sensitivity of chest CT in the face of global pandemic, I believe that each country should prepare its own practice guideline considering the availability and accessibility of resources, and the prevalence of the disease. The major concern of CT radiation dose can be also reduced down to submillisievert levels [6]. Therefore, the early employment of CT in patients with suspected COVID-19 not only contributes to early treatment and saves lives but also prevents the dissemination due to early containment of the patients.