Diagnostic accuracy of thoracic imaging modalities for the detection of COVID-19

TO THE EDITOR

We appreciate Kumar

[1]consideration of our study in their paper on the discrepancies in the clinical and radiological profiles of coronavirus disease 2019(COVID-19)[1].In this paper,the use of chest computed tomography(CT),chest X-ray(CXR),and lung ultrasound(LUS)as possible diagnostic tools for the COVID-19 is discussed.The authors cite the findings from two versions of the Cochrane Review titled “Thoracic imaging tests for the diagnosis of COVID-19.” As more information becomes available,this systematic review has aimed to keep pace with the new data.The most recent version of the review,published in March 2021,has shown differences in the sensitivities and specificities of these three image modalities compared to the findings in prior versions reported in the article by Kumar

[1].

Firstly,the authors cited the initial review by Salameh

[2],which determined that CXR had a pooled sensitivity of CXR is 82.1%(95%CI:62.5-92.7)[1,2]in patients who had COVID-19.The second version of the review,by Islam

[3],determined that CXR had a sensitivity ranging from 56.9% to 89.0% and specificity ranging from 11.1% to 88.9%[1,3]in patients with COVID-19.As opposed to the first two versions,in the third and most recent version,there was a sufficient number of studies,evaluating the diagnostic accuracy of CXR,to perform a meta-analysis.The updated version of the review conducted a meta-analysis with 9 studies and 3694 participants for CXR.The following imaging modality had sensitivity and specificity of 80.6%(95%CI:69.1-88.6)and 71.5%(95%CI:59.8-80.8)[4],respectively.These findings demonstrate that CXR is moderately sensitive and moderately specific to COVID-19,and may have the potential to be used as a secondary method for diagnosis,however,due to the limited number of studies,accuracy estimates must be carefully interpreted[4].In the upcoming fourth version of the systematic review,additional studies evaluating CXR have been included.In this review,additional analyses have been done to support our conclusion,and potential sources of variabilities in CXR accuracy estimates will be discussed.

Secondly,the article by Kumar

[1]states that chest CT may not be capable of discriminating COIVD-19 from other respiratory diseases[1].The review by Salameh

[2]obtained a pooled specificity of 18.1%(95%CI:3.71-55.8)[2]for chest CT,in cases where CT scans were used as the primary diagnostic test,which was subsequently updated to 61.1%(95%CI:42.3-77.1)in the subsequent edition[3].The third and most recent version identified that the specificity of chest CT has increased substantially to 80.0%(95%CI:74.9-84.3),based on 41 studies with 16133 patients[4].The improved specificity could be due to the stricter inclusion criteria for this version.In the most recent version,studies that published index test findings without clearly defining the images as positive or negative[4]for COVID-19,were excluded.An alternate explanation for the improved specificity could be the increase in studies that use well-developed definitions for index test positivity(

Co-RADS)[4].Furthermore,studies from the later stage of the pandemic were included with each review version which affected our specificity values through improved knowledge about the indications of COVID-19 in imaging results[4].

Lastly,the most recent version of the ‘Living’ Cochrane Systematic Review observed that in patients suspected of having COVID-19,LUS had a sensitivity and specificity rate of 86.4%(95%CI:72.7-93.9)and 54.6%(95%CI:35.3-72.6)[4],respectively.The accuracy estimates were produced through a metaanalysis including 5 studies with 446 patients[4].These findings differ from the second review version cited by Kumar

[1],which reported a sensitivity of 96.8% and sensitivity of 62.3% for LUS[1,3].The second version of the review was based off of one study,therefore a meta-analysis was not completed[1,3].The increase in studies in the most recent version reduced the role of chance in our results,and provided a better picture of the diagnostic accuracy of LUS;however,the number of studies remains small and all data should be carefully interpreted.

We would if we were taught to put the fish back when we were young. For we would have learned the truth. The decision to do right lives fresh and fragrant10 in our memory. It is a story we will proudly tell our friends and grandchildren. Not about how we had a chance to beat the system and took it, but about how we did the right thing and were forever strengthened.

In summary,the most recent version of the ‘Living’ Cochrane Systematic Review was able to perform further analyses on the diagnostic accuracy of CXR and LUS.The data demonstrates that CXR is moderately specific and moderately sensitive,while LUS is sensitive,but not specific for the diagnosis of COVID-19.Additionally,the review demonstrated that chest CT is moderately specific for the diagnosis of COVID-19.We hope that future studies will be more rigorous and transparent when designing and reporting the findings of their study.We admire the continued interest in our systematic review and will update our review as more information on the diagnostic accuracy of these imaging modalities becomes available.

All authors contributed to writing and editing this work.

FOOTNOTES

Little Vasilissa grieved greatly for her mother, and her sorrow was so deep that when the dark night came, she lay in her bed and wept and did not sleep. At length she be thought herself of the tiny doll, so she rose and took it from the pocket of her gown and finding a piece of wheat bread and a cup of kvass,7 she set them before it, and said: There, my little doll, take it. Eat a little, and drink a little, and listen to my grief. My dear mother is dead and I am lonely for her.

So they took a sad farewell of each other, and the Princess stuck the rag in front of her dress, mounted her horse, and set forth5 on the journey to her bridegroom s kingdom. After they had ridden for about an hour the Princess began to feel very thirsty,15 and said to her waiting- maid: Pray get down and fetch me some water in my golden cup out of yonder stream: I would like a drink. 16

There was no conflict of interest present in the production of this letter.

This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers.It is distributed in accordance with the Creative Commons Attribution NonCommercial(CC BYNC 4.0)license,which permits others to distribute,remix,adapt,build upon this work non-commercially,and license their derivative works on different terms,provided the original work is properly cited and the use is noncommercial.See:https://creativecommons.org/Licenses/by-nc/4.0/

47 But when the third child48 was taken away, and the Queen was again accused, and could not utter a word in her own defence, the King was obliged to give her over to the law, which decreed that she must be burnt to death

Canada

Haben Dawit 0000-0002-8052-4124;Marissa Absi 0000-0003-4581-9629;Nayaar Islam 0000-0002-1159-7629;Sanam Ebrahimzadeh 0000-0003-3890-1683;Matthew D F McInnes 0000-0001-8404-4075.

Fan JR

A

Fan JR

1 Kumar H,Fernandez CJ,Kolpattil S,Munavvar M,Pappachan JM.Discrepancies in the clinical and radiological profiles of COVID-19:A case-based discussion and review of literature.

2021;13:75-93[PMID:33968311 DOI:10.4329/wjr.v13.i4.75]

2 Salameh JP,Leeflang MM,Hooft L,Islam N,McGrath TA,van der Pol CB,Frank RA,Prager R,Hare SS,Dennie C,Spijker R,Deeks JJ,Dinnes J,Jenniskens K,Korevaar DA,Cohen JF,Van den Bruel A,Takwoingi Y,van de Wijgert J,Damen JA,Wang J;Cochrane COVID-19 Diagnostic Test Accuracy Group,McInnes MD.Thoracic imaging tests for the diagnosis of COVID-19.

2020;9:CD013639[PMID:32997361 DOI:10.1002/14651858.CD013639.pub2]

3 Islam N,Salameh JP,Leeflang MM,Hooft L,McGrath TA,van der Pol CB,Frank RA,Kazi S,Prager R,Hare SS,Dennie C,Spijker R,Deeks JJ,Dinnes J,Jenniskens K,Korevaar DA,Cohen JF,Van den Bruel A,Takwoingi Y,van de Wijgert J,Wang J,McInnes MD;Cochrane COVID-19 Diagnostic Test Accuracy Group.Thoracic imaging tests for the diagnosis of COVID-19.

2020;11:CD013639[PMID:33242342 DOI:10.1002/14651858.CD013639.pub3]

4 Islam N,Ebrahimzadeh S,Salameh JP,Kazi S,Fabiano N,Treanor L,Absi M,Hallgrimson Z,Leeflang MM,Hooft L,van der Pol CB,Prager R,Hare SS,Dennie C,Spijker R,Deeks JJ,Dinnes J,Jenniskens K,Korevaar DA,Cohen JF,Van den Bruel A,Takwoingi Y,van de Wijgert J,Damen JA,Wang J,McInnes MD;Cochrane COVID-19 Diagnostic Test Accuracy Group.Thoracic imaging tests for the diagnosis of COVID-19.

2021;3:CD013639[PMID:33724443 DOI:10.1002/14651858.CD013639.pub4]