Chest X-ray Findings and Temporal Lung Changes in Patients With COVID-19 Pneumonia

Liqa A. Rousan; Eyhab Elobeid; Musaab Karrar; Yousef Khader


BMC Pulm Med. 2020;20(245) 

In This Article


Patients' Characteristics

A total of 88 patients (50 (56.8%) females and 38 (43.2%) males) were admitted to the hospital with confirmed COVID-19 during the study period. The average (±SD) age was 35.2 ± 18.2 years (range 3–80 years). Forty-eight patients (54.5%) were symptomatic and 40 patients (45.5%) were asymptomatic. Cough and fever were the most frequent symptoms (33 and 17%, respectively). The most common co-morbidities among the patients were hypertension (15.9%) and diabetes (10.2%). The majority of the patients (96.6%) had a history of contact with infected individuals and 5.7% had history of travel overseas. The mean time from initial positive RT-PCR to negative RT-PCR was 13 ± 3 days (range 7–19 days). Table 1 shows patients' demographic characteristics, clinical presentation, co-morbidities, and clinical outcomes.

Chest x-ray Features

A total of 190 chest x-rays were performed for the 88 patients; 88 chest x-rays as baseline, and 102 chest x-rays as follow up. Of the 88 patients, 13 (14.8%) demonstrated abnormalities on chest x-rays at some time point during their illness (ten patients at baseline and three developed abnormalities during the follow-up) with a total of 59/190 (31%) abnormal chest x-rays. Seventy-five (85%) patients had no chest x-ray abnormalities although they tested positive for COVID-19 by RT-PCR.

The mean time from initial positive chest x-ray to negative chest x-ray was 10.9 ± 3.6 days (range 6–14 days). Almost half (38/75, 50.7%) of the patients with normal chest x-ray were symptomatic and the majority (12/13, 92.3%) of patients with abnormal chest x-rays were symptomatic, there was a significant association between the chest x-ray findings and the symptoms (P = 0.005). Only one patient with positive chest x-ray findings remained asymptomatic throughout the course of the illness.

During the study period, three patients (23%) progressed rapidly over an average period of 4 days with increase in the total chest x-ray severity score on average from 1 to 7. Only one elderly female patient (80 years) passed away at day 18 of onset of symptoms (Figure 1). Nine patients (69%) showed improvement in the chest x-ray findings with almost complete resolution of the abnormalities (Figure 2). The chest x-ray findings in one patient remained stable.

Figure 1.

Series chest x-rays in an 80-year-old woman with COVID-19 pneumonia. a Chest x-ray obtained on illness day 5 showed peripheral GGO in the LLZ (score 1). b Chest x-ray obtained on illness day 7 showed increase extent of the GGO diffusely involving the left lung (score 4). c Chest x-ray obtained on illness day 11 showed increase extent of the GGO involving the right lung, with increase extent of consolidation involving the left lung diffusely (Total score 8). d Chest x-ray obtained on illness day 14 showed development of reticulations in both lungs with increase extent of involvement of the RUZ. (Total score 8). e Chest x-ray obtained on illness day 17 showed extensive bilateral consolidations mainly peripherally with increased reticulations (Total score 8). f Chest x-ray obtained on illness day 18 showed extensive consolidation involving both lungs diffusely (Total score 8). The patient died on illness day 18. (GGO: ground glass opacity. LLZ: left lower zone. RUZ: right upper zone)

Figure 2.

Series chest x-rays in a 49-year-old woman with COVID-19 pneumonia. a Chest x-ray obtained on illness day 1 showed bilateral central and peripheral (diffuse) GGO bilaterally (Total score 7, right 4 Vs left 3). b Chest x-ray obtained on illness day 5 showed peaking of the findings with diffuse patchy and nodular consolidations bilaterally (Total score 8). c Chest x-ray obtained on illness day 8 showed decrease in the degree of lung involvement with reduction in the overall severity score, however, there was development of reticulations in the upper zones (Total score 5 right 3 Vs left 2). d Chest x-ray obtained on illness day 15 showed the absorption phase with regression of the consolidations into peripheral GGO seen in the lower zones bilaterally with a total score of 2

Baseline chest x-rays were done on average at day three from symptom onset. Only ten patients (11.3%) had abnormalities on their baseline chest x-ray, GGO was the only radiographic lung abnormality detected on the chest x-rays in all ten patients. Peripheral location of the opacities and right lower zone distribution were the most common locations (9/10 (90%) and 7/10(70%), respectively). Pleural effusion was found in the chest x-ray of one patient only (Table 2). Nine out of 10 (90%) patients had mild radiographic findings with total severity score of 1–2. Only one patient had a total severity score of seven (score in the right lung was 4 in the left lung was 3).

On serial follow up chest x-rays; GGO remained the most common lung abnormality pattern. At 0–5 days from onset of symptoms, the frequency of the GGO was 55% and consolidation was 20%. The rest of the chest x-rays (25%) were normal. At 6–11 days the percentage of x-rays with GGO and the consolidations increased to 70 and 30% respectively, with decrease in the number of normal chest x-rays (2/23 (9%)). One patient developed pleural effusion.

At 12–17 days, the consolidations regressed and the GGO increased (10 and 80%, respectively) with a mixed pattern of nodular consolidations and GGO in 17%. Reticulations developed within this phase comprising 8% of the abnormalities. The frequency of normal chest x-rays was zero in this group.

After 18 days, the lung abnormalities regressed (50% GGO and 17% consolidation), with increase in the frequency of normal chest x-rays (33%) indicating a healing phase. Figure 3 shows the distribution of lung abnormalities at different time intervals from onset of symptoms.

Figure 3.

Temporal change of chest x-ray findings. Stacked-bar graph showed the distribution of the lung abnormalities on chest x-ray at various time points from symptom onset. GGO was the most frequent abnormality on initial x-rays, consolidation increased in frequency till the second week then regressed into GGO which again was more frequent on subsequent chest x-rays. Mixed pattern of GGO and nodular consolidation and reticulations were noted in the second week. Normal chest x-rays increased in frequency with time as patients showed clinical improvement. GGO = ground glass opacity

The spatial distribution of the radiographic lung changes increased throughout the course of the disease. Earlier in the disease (days 0–5) bilateral involvement was seen in 30%, exclusive unilateral involvement was observed in 5/20 (25%) on the right, and 4/20 on the left (20%). The lower zones were more frequently involved (55% right, 40% left). The lung abnormalities were seen predominantly in the periphery of the lungs.

At days 11–6 from onset of symptoms, the percentage of involvement of the lower zones increased and remained the most common (65% right lower zone, 52% left lower zone). The lung abnormalities extended from the periphery to the central giving a diffuse pattern in 25%. Exclusive involvement of the right lung was noted in the majority of the x-rays (40%). Bilateral involvement was noted in 35% of the x-rays.

At days 12–17 from onset of symptoms; involvement of the left lower zone predominated (80%). Bilateral involvement was most common at this stage (80%).

After 18 days from the onset of symptoms; the right upper and right middle zones were the last to recover (66 and 50% respectively). The frequency of involvement of the other lobes decreased with fewer findings seen centrally and complete resolution of the left lung.

The left middle and left upper zones were the least to be involved throughout the course of the illness. Exclusive involvement of the central parts of the lungs was not observed in any of the chest x-rays. The rate of normal chest x-rays decreased from 25% at 0–5 days to none at 12–17 days, then increased to 33% as patients showed recovery. The specific frequencies of the spatial distribution of the lung changes are summarized in Figure 4.

Figure 4.

The spatial distribution of the lung changes at various time intervals from symptom onset. a Zonal distribution. The right lower zone remained the most frequently involved over time, the left upper and left middle zones were the least to be involved. b Horizontal distribution. The lung changes were more frequently seen in a peripheral distribution. Isolated central involvement of the lung changes was not observed in any of the chest x-rays. c Distribution according to side. Bilateral distribution of the lung changes was more common than unilateral involvement

The highest severity score recorded was eight (of maximum possible score of eight). Peak severity score was reached at day 5–10 from symptom onset, known as the peak phase at which the median chest x-ray severity score was three. Nine out of 13 patients (69%) showed complete or near complete resolution of the chest x-ray findings which was reached at day 10–15 from symptom onset known as the absorption phase (Figure 5).

Figure 5.

Temporal change of severity score. Scatter graph showed the maximum total severity score at the peak phase reaching at days 5–10 from onset of symptoms, with an average of severity score 3, (n = 13). The total severity score decreased over time as the chest x-ray findings regressed at days 10–15 from onset of symptoms (n = 9)