Chest CT in patients suspected of COVID-19 infection: A reliable alternative for RT-PCR
American Journal of Emergency Medicine 38 (2020) 2730-2732
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Chest CT in patients suspected of COVID-19 infection: A reliable alternative for RT-PCR
limited availability of COVID-19 Nucleic acid detection kit, nonspe- cific clinical manifestations as well as unavailability of reliable
standalone tool to rule out COVID-19 infection, performing chest
CT may be a helpful test for patients suspected of COVID-19 infec- tion at the beginning of admission in the emergency department. In this context, detecting bilateral, multifocal and peripherally distrib-
Dear Sir,
With the increasing prevalence of coronavirus disease-19 (COVID- 19) infection worldwide, early detection has become crucial to ensure rapid prevention and timely treatment. However, due to the unknown gene sequence of the supposed coronavirus, the reference standard test has not been established for diagnosis [1]. Several methods have been established for prompt detection of the genetic sequence of COVID-19 nucleic acid such as real-time reverse-transcriptase polymer- ase chain reaction (RT-PCR). However, this test is not readily available everywhere, especially in Developing countries. In addition, its results are not typically readily available, requiring multiple hours for the result [2].
Several studies have suggested pneumonia as the underlying mechanism of lung injury in patients with COVID-19 [3-6]. Accordingly, it is believed that the pulmonary lesions caused by COVID-19 infection are similar to those of pneumonia. More than 75% of suspected patients showed bilateral pneumonia [3]. In this context, the promising findings of several studies have highlighted the growing role of chest computed tomography scan for identifying the typical findings of suspected or confirmed cases of COVID-19 infection. The common typical chest CT scan findings were summarized in Table 1. Among the published chest CT findings related to the COVID-19 infection, the most common imaging finding was pure ground-glass opacities with the occur- rence rate of up to 74% (603 out of 807 patients). More than 62% of patients (224 out of 359) had mixed pattern opacities in their CT, which was a combination of consolidation, Ground glass opacities, and reticular opacities. In addition, the bilateral distribu- tion of lung lesions was the cardinal hallmark of COVID-19 with an occurrence rate of up to 76% (365 out of 476 patients). More than 66% of lung lesions was peripherally distributed (399 out of 601 patients).
Some studies have reported that chest CT images have the sensi- tivity of 80-90% and specificity of 82.8-96% for detecting the lung le- sions in patients with COVID-19 (area under the receiver operating characteristic curve, ranged between 0.87 and 0.96) [4,20]. Accord- ingly, the findings of the available studies support the use of Chest CT scan as a reliable test for detecting pulmonary lesions related to the COVID-19 infection. Some studies have reported that chest CT manifestations may associate with the progression and prognosis of COVID-19 [19].
Timely detection of COVID-19 patients is of crucial importance, particularly in those with false-negative RT-PCR or those without symptoms. Given the large global outbreak of COVID-19 infection,
uted ground-glass opacities with or without consolidation could be a valuable diagnostic clue. These findings were considered highly suspicious of COVID-19 infection; however, these findings can be further confirmed by positive real-time RT-PCR assay for COVID- 19 infection.
An important issue is that excessive demand for CT imaging of patient with COVID-19 not only increases costs, but also pose sig- nificant risk for transmission or environmental contamination. Therefore, there are several significant considerations for both emergency and radiology departments during the work-up of each patient with COVID-19 that impact use of chest CT, including the safety of personnel, the decontamination of radiology equip- ment, and the duration of CT room unavailability. Among these cases, the length of time the CT device is out of service has a sig- nificant role in increasing the waiting time for performing CT scan and then increasing the emergency department crowding. Cur- rently, there are no valid guidelines for determining the time in- terval for subsequent patients. However, between 30 min and
1 h of room downtime is recommended for environmental cleaning and equipment decontamination using hospital approved methods such as hydrogen peroxide vapor, ultraviolet light, Phe- nolic or sodium hypochlorite [21,22]. Accordingly, it is recom- mended that CT imaging be reserved for emergent cases with suspected COVID-19 infection. As a general rule, standardized in- fection control and prevention practices should be implemented for all patients with respiratory illness [23]. Protecting radiology personnel from the hazard posed by a patient with COVID-19 in- volves employing droplet precaution, using appropriate Personal protective equipment, limiting the number of staff entering the patient’s room, and careful screening of staff to identify possible cases. Environmental decontamination of CT rooms could be achieved thorough cleaning of surfaces with common chemical disinfectants, such as sodium hypochlorite, Phenolic, bleach, hy- drogen peroxide, or quaternary ammonium compounds, by some- one with appropriate protective equipment, maintaining proper ventilation and airflow in the CT scanner rooms and putting CT equipment out of commission for specific time for cleaning. In this regard, United States Environmental Protection Agency pub- lished some registered disinfectants for use against COVID-19 (available at: https://www.epa.gov/pesticide-registration/list-n- disinfectants-use-against-sars-cov-2). In addition, chest CT imag- ing should be performed at sites with less traffic to avoid unin- fected patient and staff exposure. Portable chest X-ray in patient rooms, radiology outposts, and isolated CT imaging rooms are op- tions, if available, to limit contamination of radiology equipment
https://doi.org/10.1016/j.ajem.2020.04.016
0735-6757/(C) 2020
Chest CT in patients suspected of COVID-19 infection: A reliable alternative for RT-PCR 2731
Table 1
Chest CT findings of patients with COVID-19 infection.
|
CT findings |
Author [ref] |
n |
Total |
% |
CT findings |
Author [ref] |
n |
Total |
% |
|
Peripheral distribution |
Xu [7] |
46 |
90 |
51.11 |
Consolidation |
Xu [7] |
12 |
90 |
13.33 |
|
Shi [8] |
44 |
81 |
54.32 |
Shi [8] |
14 |
81 |
17.28 |
||
|
Zhao [9] |
88 |
101 |
87.13 |
Zhao [9] |
44 |
101 |
43.56 |
||
|
Zhou [10] |
48 |
62 |
77.42 |
Zhou [10] |
21 |
62 |
33.87 |
||
|
Cheng [11] |
11 |
11 |
100.0 |
Cheng [11] |
6 |
11 |
54.55 |
||
|
Xiong [12] |
12 |
42 |
28.57 |
Xu YH [6] |
15 |
41 |
36.59 |
||
|
Song [1] |
44 |
51 |
86.27 |
Xiong [12] |
23 |
42 |
54.76 |
||
|
Chung [13] |
7 |
21 |
33.33 |
Xia [14] |
10 |
20 |
50.00 |
||
|
Xu YH [6] |
39 |
41 |
95.12 |
Li [15] |
3 |
51 |
5.88 |
||
|
Wu [16] |
42 |
80 |
52.50 |
Pan [5] |
12 |
63 |
19.05 |
||
|
Ng [17] |
18 |
21 |
85.71 |
Song [1] |
28 |
51 |
54.90 |
||
|
Total |
399 |
601 |
66.39 |
Huang [18] |
41 |
41 |
100.0 |
||
|
Bilateral Lung involvement |
Xu [7] |
53 |
90 |
58.89 |
Liu [19] |
8 |
73 |
10.96 |
|
|
Shi [8] |
64 |
81 |
79.01 |
Wu [16] |
50 |
80 |
62.50 |
||
|
Zhao [9] |
83 |
101 |
82.18 |
Ng [17] |
13 |
21 |
61.90 |
||
|
Song [1] |
44 |
51 |
86.27 |
Total |
300 |
828 |
36.23 |
||
|
Huang [18] |
40 |
41 |
97.56 |
Reticular pattern |
Zhao [9] |
49 |
101 |
48.51 |
|
|
Chung [13] |
16 |
21 |
76.19 |
Cheng [11] |
9 |
11 |
81.82 |
||
|
Xia [14] |
10 |
20 |
50.00 |
Song [1] |
11 |
51 |
21.57 |
||
|
Liu [19] |
55 |
73 |
75.34 |
Total |
69 |
163 |
42.33 |
||
|
Total |
365 |
478 |
76.36 |
Mixed pattern |
Zhao [9] |
65 |
101 |
64.36 |
|
|
Multifocal involvement |
Xu [7] |
62 |
90 |
68.89 |
Zhou [10] |
39 |
62 |
62.90 |
|
|
Shi [8] |
30 |
81 |
37.04 |
Cheng [11] |
7 |
11 |
63.64 |
||
|
Zhao [9] |
55 |
101 |
54.46 |
Xu YH [6] |
25 |
41 |
60.98 |
||
|
Zhou [10] |
52 |
62 |
83.87 |
Li [15] |
28 |
51 |
54.90 |
||
|
Song [1] |
46 |
51 |
90.20 |
Song [1] |
38 |
51 |
74.51 |
||
|
Cheng [11] |
5 |
11 |
45.45 |
Chung [13] |
18 |
21 |
85.71 |
||
|
Xiong [12] |
32 |
42 |
76.19 |
Ng [17] |
4 |
21 |
19.05 |
||
|
Pan [5] |
28 |
63 |
44.44 |
Total |
224 |
359 |
62.40 |
||
|
Chung [13] |
15 |
21 |
71.43 |
Air bronchogram sign |
Xu [7] |
7 |
90 |
7.78 |
|
|
Total |
325 |
522 |
62.26 |
Shi [8] |
38 |
81 |
46.91 |
||
|
Ground glass opacification |
Xu [7] |
65 |
90 |
72.22 |
Zhou [10] |
45 |
62 |
72.58 |
|
|
Shi [8] |
53 |
81 |
65.43 |
Cheng [11] |
8 |
11 |
72.73 |
||
|
Zhao [9] |
87 |
101 |
86.14 |
Xu YH [6] |
22 |
41 |
53.66 |
||
|
Xu YH [6] |
30 |
41 |
73.17 |
Xiong [12] |
14 |
42 |
33.33 |
||
|
Zhou [10] |
25 |
62 |
40.32 |
Li [15] |
35 |
51 |
68.63 |
||
|
Cheng [11] |
11 |
11 |
100.0 |
Song [1] |
41 |
51 |
80.39 |
||
|
Li [15] |
18 |
51 |
35.29 |
Total |
210 |
429 |
48.95 |
||
|
Pan [5] |
54 |
63 |
85.71 |
Adjacent pleura thickening |
Xu [7] |
50 |
90 |
55.56 |
|
|
Xia [14] |
12 |
20 |
60.00 |
Shi [8] |
26 |
81 |
32.10 |
||
|
Song [1] |
39 |
51 |
76.47 |
Zhou [10] |
30 |
62 |
48.39 |
||
|
Huang [18] |
41 |
41 |
100.0 |
Total |
106 |
233 |
45.49 |
||
|
Chung [13] |
12 |
21 |
57.14 |
Pleural effusion |
Xu [7] |
4 |
90 |
4.44 |
|
|
Liu [19] |
65 |
73 |
89.04 |
Shi [8] |
4 |
81 |
4.94 |
||
|
Wu [16] |
73 |
80 |
91.25 |
Zhao [9] |
14 |
101 |
13.86 |
||
|
Ng [17] |
18 |
21 |
85.71 |
Xu YH [6] |
4 |
41 |
9.76 |
||
|
Total |
603 |
807 |
74.72 |
Zhou [10] |
6 |
62 |
9.68 |
||
|
Crazy paving appearance |
Xu [7] |
11 |
90 |
12.22 |
Cheng [11] |
0 |
11 |
0.00 |
|
|
Shi [8] |
8 |
81 |
9.88 |
Xiong [12] |
5 |
42 |
11.90 |
||
|
Chung [13] |
4 |
21 |
19.05 |
Li [15] |
1 |
51 |
1.96 |
||
|
Liu [19] |
28 |
73 |
38.36 |
Song [1] |
4 |
51 |
7.84 |
||
|
Wu [16] |
23 |
80 |
28.75 |
Liu [19] |
3 |
73 |
4.11 |
||
|
Total |
74 |
345 |
21.45 |
Wu [16] |
5 |
80 |
6.25 |
||
|
Interlobular septal thickening |
Xu [7] |
33 |
90 |
36.67 |
Total |
50 |
683 |
7.32 |
|
|
Shi [8] |
28 |
81 |
34.57 |
Lymphadenopathy |
Shi [8] |
5 |
81 |
6.17 |
|
|
Zhao [9] |
29 |
101 |
28.71 |
Zhao [9] |
1 |
101 |
0.99 |
||
|
Xu YH [6] |
33 |
41 |
80.49 |
Xu [7] |
1 |
90 |
1.11 |
||
|
Xiong [12] |
17 |
42 |
40.48 |
Cheng [11] |
0 |
11 |
0.00 |
||
|
Li [15] |
36 |
51 |
70.59 |
Xiong [12] |
12 |
42 |
28.57 |
||
|
Liu [19] |
19 |
73 |
26.03 |
Song [1] |
3 |
51 |
5.88 |
||
|
Wu [16] |
47 |
80 |
58.75 |
Wu [16] |
3 |
80 |
3.75 |
||
|
Total |
242 |
559 |
43.29 |
Total |
25 |
456 |
5.48 |
||
|
Bronchiolectasis |
Shi [8] |
9 |
81 |
11.11 |
|||||
|
Zhao [9] |
53 |
101 |
52.48 |
||||||
|
Zhou [10] |
20 |
62 |
32.26 |
||||||
|
Total |
82 |
244 |
33.61 |
and environment [22]. Undoubtedly, performing these protective measures may reduce access to CT imaging suites, leading prob- lems for patient care, especially critically ill patients.
Declaration of funding
Nil.
2732 Chest CT in patients suspected of COVID-19 infection: A reliable alternative for RT-PCR
Declaration of competing interest
The authors declare that there is no conflict of interest re- garding the publication of this paper. In addition, they have no relevant affiliations or financial involvement with any orga- nization or entity with a financial interest in or financial con- flict with the subject matter or materials discussed in the manuscript.
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Hadi Majidi, M.D. Department of Radiology, Faculty of Medicine, Orthopedic Research Center, Mazandaran University of Medical Sciences, Sari, Iran
E-mail address: [email protected]
Fatemeh Niksolat, M.D. Department of Internal Medicine and Rheumatology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
Corresponding author.
E-mail address: [email protected]
24 February 2020