CT images with yielded 98% sensitivity play an important role in the diagnosis and evaluation of COVID-19 and can be used as a standard method for rapid diagnosis of COVID-19 to manage patients [4-16]. The present study was conducted on 552 patients with clinical suspicion who referred for HRCT and had signs of involvement in the CT images. The most common suggestive findings in patients were ground glass opacity, peripheral distribution, and posterior distribution.The prevalence of ground glass opacity in the study population was 87.3%, which varied from 41% to 100% in other studies [9, 14, 17-28] and the prevalence of this finding was 67% given the difference in sample size in different studies and conducting the meta-analysis on these studies (Table 3). Peripheral distribution was the second most common finding in 82.4% of the study population. The prevalence of this finding in other studies ranged from 33% to 98% [15-21, 23, 25, 27, 28]. The meta-analysis conducted on the present study and other studies presented the peripheral distribution with 79% prevalence as the most common CT finding in these patients (Table 3).
The most common inconsistent findings in patients were pleural effusion, peribronchovascular distribution, and lymphadenopathy. Pleural effusion was 7.6% in the present study, which ranged between 2% to 9.7% in other studies, and the combination of the results of the present study and other studies estimated a 7% pleural effusion (Table 3). Lymphadenopathy in the CT scan was 5.1% higher than the value reported by other studies, such that this finding was not observed in two studies [15, 27] while it was 2.7% in one study [17] and 6% in another study. The total estimation was 4% (Table 3)
A halo sign of 1.6% was an uncommon finding in the present study, while other studies reported 11.1% to 64% [15, 20, 29]. The cumulative rate of the present study and other studies estimated a 41% rate of halo sign (Table 3). In addition, a similar situation occurred with crazy-paving as an uncommon finding in the present study which varied from 1.4% in this study to 12-89% in other studies [18-20 and 24]. The meta-analysis of the present study and other studies provided a rate of 32% for this finding.
Most CT findings in the present study showed no significant difference between genders and age groups, except for peripheral distribution, round opacities, single lobe, and pleural effusion, which showed a significant difference between the age groups under and over 50 years old. In a study by Song et al., ground glass opacity and consolidative opacities were significantly different between age groups under and over 50 years old [28].
Mean age of participants was 51.2±14.8 years. The male/female sex ratio was 1.38 Similar to the results of the present study, in a study conducted on 1,099 patients in China, the mean age of patients was 47 years, and the same sex ratio was observed [9].
The present study utilized an acceptable sample size which is one of the strengths of the present study. One of the weaknesses of the study is the lack of diagnostic confirmation by RT-PCR test, which was not possible for all patients due to the epidemic that occurred and the limited number of tests in Iran at the beginning of the epidemic. Other limitations of the study include the lack of a standard reporting format for the chest CT scans in these patients.
Table 3. CT-Scan findings in different study and pooled estimation of these findings
Author
|
Sample size
|
Ground-glass opacity
|
Peripheral distribution
|
Pleural effusion
|
Lymphadenopathy
|
Halo sign
|
Crazy-paving
|
Guan, WJ [9]
|
975
|
56.4
|
|
|
|
|
|
Wu, J [14]
|
80
|
91.0
|
|
|
|
|
|
Li,Y [15]
|
51
|
|
90.2
|
2.0
|
0.0
|
21.5
|
|
Bai, HX [17]
|
424
|
91.0
|
80.0
|
4.1
|
2.7
|
|
|
Chung, M [18]
|
21
|
87.0
|
33.0
|
|
|
|
19.0
|
Guan, CS [19]
|
47
|
100.0
|
93.6
|
|
|
|
89.4
|
Han, R [20]
|
108
|
60.0
|
90.0
|
|
|
64.0
|
40.0
|
Liu, H [21]
|
59
|
72.0
|
98.0
|
|
|
|
|
Liu, KC [22]
|
73
|
59.0
|
|
3.4
|
|
|
|
Shi, H [23]
|
81
|
65.0
|
54.0
|
|
|
|
|
Xu, X [24]
|
90
|
72.0
|
|
|
|
|
12.0
|
Zhao, W [25]
|
101
|
86.1
|
87.1
|
|
|
|
|
Zhu, W [26]
|
32
|
47.0
|
|
|
|
|
|
Li, K [27]
|
56
|
80.4
|
87.5
|
8.9
|
0.0
|
|
|
Song, F [28]
|
51
|
77
|
|
8
|
6
|
|
|
Zhou, S [29]
|
62
|
|
77.4
|
9.7
|
|
|
|
Yoon, SH [30]
|
9
|
|
|
|
|
11.1
|
|
Majidi, H (Present)
|
552
|
87.3
|
82.4
|
7.6
|
5.1
|
1.6
|
1.4
|
Pooled estimation (CI95%) with meta-analysis
|
|
67 (58-76)
|
79 (66-92)
|
7 (-24-39)
|
4 (-26-35)
|
41 (11-72)
|
32 (4-59)
|