Radiographic features of baseline CXR
The CXR patterns we evaluated were GGO, lung consolidation and reticular pattern, as isolated finding or as a combination of the three patterns.
Of the 940 positive chest radiographs, 638 (67.9%) showed the presence of a single pattern, while 273 (29%) had the compresence of two patterns and 29 (3.1%) presented three patterns contemporarily.
The most frequent radiographic pattern, either isolated or combined, was the GGO (621/940, 66.1%), followed by reticular pattern (426/940, 45.3%) and consolidation (224/940, 23.8%).
Peripheral (524/940, 55.8%) and middle-lower zone distribution (331/940, 33.1%) were the most common locations, and the 73.9% (695/940) had bilateral involvement.
Pleural effusion was described in only 7 cases.
The frequency of the three patterns and their distribution are listed in Table 2.
Table 2 - Findings on positive baseline CXR (n = 940)
|
Patterns (alone or combined)
|
|
GGO
|
621 (66.1%)
|
Reticular pattern
|
426 (45.3%)
|
Consolidation/s
|
224 (23.8%)
|
Number of patterns present
|
|
One
|
638 (67.9%)
|
Two
|
273 (29%)
|
Three
|
29 (3.1%)
|
Pattern combinations
|
|
GGO
|
363 (38.6%)
|
GGO + reticular pattern
|
184 (19.6%)
|
Reticular pattern
|
169 (18%)
|
Consolidations
|
90 (9.6%)
|
GGO + consolidations
|
45 (4.8%)
|
Reticular pattern + consolidations
|
40 (4.3%)
|
GGO + reticular pattern + consolidations
|
29 (3.1%)
|
Single consolidation
|
16 (1.7 %)
|
Single consolidation + reticular pattern
|
4 (0.4%)
|
Axial distribution
|
|
Peripheral
|
524 (55.7%)
|
Central
|
311 (33.1%)
|
Diffuse (Central + Peripheral)
|
105 (11.2%)
|
Longitudinal distribution
|
|
Middle-inferior
|
375 (39.9%)
|
Inferior
|
208 (22.1%)
|
Superior-middle
|
78 (8.3%)
|
Middle
|
77 (8.2%)
|
Superior
|
46 (4.9%)
|
Superior-inferior
|
30 (3.2%)
|
Diffuse (Superior-middle-inferior)
|
126 (13.4%)
|
Laterality
|
|
Unilateral
|
245 (26.1%)
|
Bilateral
|
695 (73.9%)
|
Radiographic features of follow-up CXR
382 patients underwent a follow-up CXR. The median time between the two examinations was 4 days (IQR 3; range 1–17).
31 patients had negative radiographic findings on the first examination: the second assessment showed radiographic abnormalities in 26 cases, while confirmed negative findings in 5 cases. In the remaining 351 patients the first CXR examinations yielded positive results, confirmed on the second CXR; therefore, the overall prevalence of positive follow-up CXR was 98.7% (377/382).
In 262/382 cases (68.6%) we noticed a worsening of the imaging findings, 73/382 (19.1%) CXR were not significantly changed while in 47/382 (12.3%) cases there was an improvement.
The prevalence of the key patterns in the follow-up group changed as follows: consolidation was described in the 26% (99/382) of cases on the baseline CXR, while was present in the 53.4% (204/382) on the follow-up CXR; on the other hand, the prevalence of GGO and reticular pattern decreased on the follow-up CXR, passing from 59.4% (227/382) to 51% (195/382) and from 42.4% (162/382) to 37.2% (142/382), respectively (fig. 5).
As seen above, the prevalence of consolidation in the follow-up group, increased significantly (from 26% to 53.4% - p-value < 0.001); furthermore, 116 patients with no consolidations on the baseline CXR showed consolidation on the follow-up CXR, while only in 12 cases consolidation was seen on the first CXR and was no longer present at the follow-up.
Peripheral (48.1%) and middle-lower zone distribution (40.2%) remained the most common locations of the lung abnormalities, but we observed a greater involvement of the lung parenchyma both on axial and longitudinal distribution, in particular central-peripheral distribution was present in the 47.6% of patients (in contrast with 39.6% on the baseline CXR) and superior-middle-inferior distribution was described in the 27.9% of patients (in contrast with 16.8% on the baseline CXR). Moreover, the percentage of bilateral involvement of the lung increased from 76.6% to 87.7%.
Other findings recorded were pleural effusion (6/382), pneumothorax (2/382) and pneumomediastinum (2/382).
The comparison between the findings on follow-up and baseline CXR is listed in Table 3.
Table 3 - Comparison of findings in patient with baseline and follow-up CXR (n = 382)
|
|
Baseline CXR
|
Follow-up CXR
|
p-value
|
Positive
|
351 (91.2%)
|
377 (98.7%)
|
…
|
No abnormalities
|
31 (8.8%)
|
5 (1.3%)
|
…
|
|
|
|
|
Patterns (alone or combined)
|
|
|
|
GGO
|
227 (59.4%)
|
195 (51%)
|
< 0.001
|
Reticular pattern
|
162 (42.4%)
|
142 (37.2%)
|
0.0181
|
Consolidation/s
|
99 (26%)
|
204 (53.4%)
|
0.0039
|
|
|
|
|
Axial distribution*
|
|
|
|
Peripheral
|
181 (51.6%)
|
169 (48.1%)
|
< 0.001
|
Central
|
32 (9.1%)
|
15 (4.3%)
|
< 0.001
|
Diffuse (Central + Peripheral)
|
138 (76.6%)
|
167 (87.7%)
|
< 0.001
|
|
|
|
|
Longitudinal distribution*
|
|
|
|
Middle-inferior
|
139 (39.6%)
|
141 (40.2%)
|
< 0.001
|
Inferior
|
60 (17.1%)
|
37 (10.5%)
|
< 0.001
|
Superior-middle
|
32 (9.1%)
|
33 (9.4%)
|
< 0.001
|
Middle
|
29 (8.3%)
|
22 (6.3%)
|
< 0.001
|
Superior
|
21 (6%)
|
7 (2%)
|
< 0.001
|
Superior-inferior
|
11 (3.1%)
|
13 (3.7%)
|
< 0.001
|
Diffuse (Superior-middle-inferior)
|
59 (16.8%)
|
98 (27.9%)
|
< 0.001
|
|
|
|
|
Laterality*
|
|
|
|
Unilateral
|
82 (23.4%)
|
43 (12.3%)
|
< 0.001
|
Bilateral
|
269 (76.6%)
|
308 (87.7%)
|
< 0.001
|
*Percentages refer to patients with positive baseline CXR (n = 351)
|