Reply:
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* R.M. Kwee

I thank Li and colleagues for their interest in our article “CT Scanning in Suspected Stroke or Head Trauma: Is it Worth Going the Extra Mile and Including the Chest to Screen for COVID-19 Infection?”1 Our article title is a question, which does not imply that using chest CT to screen for coronavirus disease 2019 (COVID-19) in this patient population may add value. The Fleischner Society’s position article on the use of chest imaging during the COVID-19 pandemic2 did not specifically address whether additional chest CT should be performed to detect COVID-19 in patients who undergo extrathoracic CT in regions of high COVID-19 prevalence. Our study1 provides new scientific information, and we address the possible pros and cons of performing additional chest CT for COVID-19 detection in patients who undergo head CT for suspected stroke or head trauma in a COVID-19–endemic region. We clearly stated that the data from our study may be used to weigh the potential advantages and disadvantages of performing additional chest CT. This is up to the readers of our article. However, I certainly appreciate that Li and colleagues are sharing their valuable thoughts. They relied on reverse transcription polymerase chain reaction (RT-PCR) testing for diagnosing COVID-19 infection. Unfortunately, RT-PCR is an imperfect test, with a reported pooled sensitivity of 89% (95% CI, 81%–94%).3 Even repeat RT-PCR testing may yield a false-negative result in patients with COVID-19.4 Li and colleagues did not perform chest CT. Therefore, from a scientific point of view, it remains speculative whether chest CT would truly have had a low diagnostic yield in their stroke population during the rise and peak of the COVID-19 pandemic.

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## References

1.  1.Kwee RM, Krdzalic J, Fasen BA, et al. CT scanning in suspected stroke or head trauma: is it worth going the extra mile and including the chest to screen for COVID-19 infection? AJNR Am J Neuroradiol 2020;41:1165–69 doi:10.3174/ajnr.A6607 pmid:32439651
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiI0MS83LzExNjUiO3M6NDoiYXRvbSI7czoyMDoiL2FqbnIvNDEvMTEvRTg4LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

2.  2.Rubin GD, Ryerson CJ, Haramati LB, et al. The role of chest imaging in patient management during the COVID-19 pandemic: a multinational consensus statement from the Fleischner Society. Chest 2020;158:106–16 doi:10.1016/j.chest.2020.04.003 pmid:32275978
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/j.chest.2020.04.003&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=32275978&link_type=MED&atom=%2Fajnr%2F41%2F11%2FE88.atom) 

3.  3.Li D, Wang D, Dong J, et al. False-negative results of real-time reverse-transcriptase polymerase chain reaction for severe acute respiratory syndrome coronavirus, 2: role of deep-learning-based CT diagnosis and insights from two cases. Korean J Radiol 2020;21:505–08 doi:10.3348/kjr.2020.0146 pmid:32174053
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.3348/kjr.2020.0146&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=http://www.n&link_type=MED&atom=%2Fajnr%2F41%2F11%2FE88.atom) 

4.  4.Kim H, Hong H, Yoon SH. Diagnostic performance of CT and reverse transcriptase-polymerase chain reaction for coronavirus disease 2019: a meta-analysis. Radiology 2020 Apr 17. [Epub ahead of print] doi:10.1148/radiol.2020201343 pmid:32301646
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1148/radiol.2020201343&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=32301646&link_type=MED&atom=%2Fajnr%2F41%2F11%2FE88.atom) 

*   © 2020 by American Journal of Neuroradiology