CT Lung Abnormalities after COVID-19 at 3 Months and 1 Year after Hospital Discharge

Longitudinal analysis of the lung proteome reveals persistent repair months after mild to moderate COVID-19

In order to assess homeostatic mechanisms in the lung after COVID-19, changes in the protein signature of bronchoalveolar lavage from 45 patients with mild to moderate disease at three phases (acute, recovery, and convalescent) are evaluated over a year. During the acute phase, inflamed and uninflamed phenotypes are characterized by the expression of tissue repair and host defense response molecules. With recovery, inflammatory and fibrogenic mediators decline and clinical symptoms abate. However, at 9 months, quantified radiographic abnormalities resolve in the majority of patients, and yet compared to healthy persons, all showed ongoing activation of cellular repair processes and depression of the renin-kallikrein-kinin, coagulation, and complement systems. This dissociation of prolonged reparative processes from symptom and radiographic resolution suggests that occult ongoing disruption of the lung proteome is underrecognized and may be relevant to recovery from other serious viral pneumonias.

Chest CT Findings at Six Months Following COVID-19 ARDS - Correlation With the mMRC Dyspnea Scale and Pulmonary Function Tests

Background: Many survivors of severe COVID-19 pneumonia experience lingering respiratory issues. There is limited research on follow-up chest imaging findings in patients with COVID-19 ARDS, particularly in relation to their mMRC dyspnea scores and pulmonary function tests (PFTs). This study addresses this gap by investigating the clinical characteristics, mMRC dyspnea scores, PFTs, and chest CT findings of COVID-19 ARDS patients at the 6 months post-recovery. By analyzing these variables together, we aim to gain a better understanding of the long-term health consequences of COVID-19 ARDS. Methods: This prospective observational study included 56 subjects with COVID-19 ARDS with dyspnea at the six-month follow-up visits. These patients were evaluated by chest CT, mMRC dyspnea scale, and PFT. The CT severity score was calculated individually for each of the four major imaging findings - ground glass opacities (GGOs), parenchymal/atelectatic bands, reticulations/septal thickening, and consolidation - using a modified CT severity scoring system. Statistics were carried out to find any association between individual CT chest findings and the mMRC dyspnea scale and forced vital capacity (FVC). p values < 0.05 were considered statistically significant. Results: Our study population had a mean age of 55.86 ± 9.60 years, with 44 (78.6%) being men. Grades 1, 2, 3, and 4 on the mMRC dyspnea scale were seen in 57.1%, 30.4%, 10.7%, and 1.8% of patients respectively. Common CT findings observed were GGOs (94.6%), reticulations/septal thickening (96.4%), parenchymal/atelectatic bands (92.8%), and consolidation (14.3%). The mean modified CT severity scores for GGOs, reticulations/septal thickening, parenchymal/atelectatic bands, and consolidation were 10.32 ± 5.51 (range: 0-21), 7.66 ± 4.33 (range: 0-19), 4.77 ± 3.03 (range: 0-14) and 0.29 ± 0.91 (range 0-5) respectively. Reticulations/septal thickening (p = 0.0129) and parenchymal/atelectatic bands (p = 0.0453) were associated with an increased mMRC dyspnea scale. Parenchymal/atelectatic bands were also associated with abnormal FVC (<80%) (p = 0.0233). Conclusion: Six-month follow-up chest CTs of COVID-19 ARDS survivors with persistent respiratory problems showed a statistically significant relationship between increased mMRC dyspnea score and imaging patterns of reticulations/septal thickening and parenchymal/atelectatic bands; while parenchymal/atelectatic bands also showed a statistically significant correlation with reduced FVC.

Long-term radiological and pulmonary function abnormalities at 3 years after COVID-19 hospitalisation: a longitudinal cohort study

BACKGROUND

This study aimed to evaluate the longitudinal progression of residual lung abnormalities (ground-glass opacities, reticulation and fibrotic-like changes) and pulmonary function at 3 years following coronavirus disease 2019 (COVID-19).

METHODS

This prospective, longitudinal cohort study enrolled COVID-19 survivors who exhibited residual lung abnormalities upon discharge from two hospitals. Follow-up assessments were conducted at 6 months, 12 months, 2 years and 3 years post-discharge, and included pulmonary function tests, 6-min walk distance (6MWD), chest computed tomography (CT) scans and symptom questionnaires. Non-COVID-19 controls were retrospectively recruited for comparative analysis.

RESULTS

728 COVID-19 survivors and 792 controls were included. From 6 months to 3 years, there was a gradual improvement in reduced diffusing capacity of the lung for carbon monoxide (D LCO <80% predicted: 49% versus 38%; p=0.001), 6MWD (496 versus 510 m; p=0.002) and residual lung abnormalities (46% versus 36%; p<0.001), regardless of disease severity. Patients with residual lung abnormalities at 3 years more commonly had respiratory symptoms (32% versus 16%; p<0.001), lower 6MWD (494 versus 510 m; p=0.003) and abnormal D LCO (57% versus 27%; p<0.001) compared with those with complete resolution. Compared with controls, the proportions of D LCO impairment (38% versus 17%; p<0.001) and respiratory symptoms (23% versus 2.2%; p<0.001) were significantly higher in the matched COVID-19 survivors at the 3-year follow-up.

CONCLUSIONS

Most patients exhibited improvement in radiological abnormalities and pulmonary function over time following COVID-19. However, more than a third continued to have persistent lung abnormalities at the 3-year mark, which were associated with respiratory symptoms and reduced diffusion capacity.

A Literature Review on the Relative Diagnostic Accuracy of Chest CT Scans versus RT-PCR Testing for COVID-19 Diagnosis

BACKGROUND

Reverse transcription polymerase chain reaction (RT-PCR) is the main technique used to identify COVID-19 from respiratory samples. It has been suggested in several articles that chest CTs could offer a possible alternate diagnostic tool for COVID-19; however, no professional medical body recommends using chest CTs as an early COVID-19 detection modality. This literature review examines the use of CT scans as a diagnostic tool for COVID-19.

METHOD

A comprehensive search of research works published in peer-reviewed journals was carried out utilizing precisely stated criteria. The search was limited to English-language publications, and studies of COVID-19-positive patients diagnosed using both chest CT scans and RT-PCR tests were sought. For this review, four databases were consulted: these were the Cochrane and ScienceDirect catalogs, and the CINAHL and Medline databases made available by EBSCOhost.

FINDINGS

In total, 285 possibly pertinent studies were found during an initial search. After applying inclusion and exclusion criteria, six studies remained for analysis. According to the included studies, chest CT scans were shown to have a 44 to 98% sensitivity and 25 to 96% specificity in terms of COVID-19 diagnosis. However, methodological limitations were identified in all studies included in this review.

CONCLUSION

RT-PCR is still the suggested first-line diagnostic technique for COVID-19; while chest CT is adequate for use in symptomatic patients, it is not a sufficiently robust diagnostic tool for the primary screening of COVID-19.

Pulmonary redox imbalance drives early fibroproliferative response in moderate/severe coronavirus disease-19 acute respiratory distress syndrome and impacts long-term lung abnormalities

BACKGROUND

COVID-19-associated pulmonary fibrosis remains frequent. This study aimed to investigate pulmonary redox balance in COVID-19 ARDS patients and possible relationship with pulmonary fibrosis and long-term lung abnormalities.

METHODS

Baseline data, chest CT fibrosis scores, N-terminal peptide of alveolar collagen III (NT-PCP-III), transforming growth factor (TGF)-β1, superoxide dismutase (SOD), reduced glutathione (GSH), oxidized glutathione (GSSG) and malondialdehyde (MDA) in bronchoalveolar lavage fluid (BALF) were first collected and compared between SARS-CoV-2 RNA positive patients with moderate to severe ARDS (n = 65, COVID-19 ARDS) and SARS-CoV-2 RNA negative non-ARDS patients requiring mechanical ventilation (n = 63, non-ARDS). Then, correlations between fibroproliferative (NT-PCP-III and TGF-β1) and redox markers were analyzed within COVID-19 ARDS group, and comparisons between survivor and non-survivor subgroups were performed. Finally, follow-up of COVID-19 ARDS survivors was performed to analyze the relationship between pulmonary abnormalities, fibroproliferative and redox markers 3 months after discharge.

RESULTS

Compared with non-ARDS group, COVID-19 ARDS group had significantly elevated chest CT fibrosis scores (p < 0.001) and NT-PCP-III (p < 0.001), TGF-β1 (p < 0.001), GSSG (p < 0.001), and MDA (p < 0.001) concentrations on admission, while decreased SOD (p < 0.001) and GSH (p < 0.001) levels were observed in BALF. Both NT-PCP-III and TGF-β1 in BALF from COVID-19 ARDS group were directly correlated with GSSG (p < 0.001) and MDA (p < 0.001) and were inversely correlated with SOD (p < 0.001) and GSH (p < 0.001). Within COVID-19 ARDS group, non-survivors (n = 28) showed significant pulmonary fibroproliferation (p < 0.001) with more severe redox imbalance (p < 0.001) than survivors (n = 37). Furthermore, according to data from COVID-19 ARDS survivor follow-up (n = 37), radiographic residual pulmonary fibrosis and lung function impairment improved 3 months after discharge compared with discharge (p < 0.001) and were associated with early pulmonary fibroproliferation and redox imbalance (p < 0.01).

CONCLUSIONS

Pulmonary redox imbalance occurring early in COVID-19 ARDS patients drives fibroproliferative response and increases the risk of death. Long-term lung abnormalities post-COVID-19 are associated with early pulmonary fibroproliferation and redox imbalance.

[Clinical and morphological features of lung injury long-term after SARS-CoV-2 recovery]

AIM

To study the clinical and histological profile of lung tissue in patients with persistent pulmonary disease, respiratory symptoms and CT findings after SARS-CoV-2 infection.

MATERIALS AND METHODS

The study included 15 patients (7 females and 8 males) with a mean age of 57.7 years. All patients underwent laboratory tests, chest computed tomography, echocardiography, and pulmonary function tests. Pulmonary tissue and bronchoalveolar lavage samples were obtained by fibrobronchoscopy, transbronchial forceps (2 patients), and lung cryobiopsy (11 patients); open biopsy was performed in 2 patients. Cellular composition, herpesvirus DNA, SARS-CoV-2, Mycobacterium tuberculosis complex, galactomannan optical density index, and bacterial and fungal microflora growth were determined in bronchoalveolar lavage. SARS-CoV-2 was also identified in samples from the nasal mucosa, throat and feces using a polymerase chain reaction.

RESULTS

The results showed no true pulmonary fibrosis in patients recovered from SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings after SARS-CoV-2 infection. The observed changes comply with the current and/or resolving infection and inflammatory process.

CONCLUSION

Thus, no true pulmonary fibrosis was found in patients after SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings. The observed changes comply with the current and/or resolving infection and inflammatory process.

Improved pulmonary function and exercise tolerance despite persistent pulmonary fibrosis over 1 year after severe COVID-19 infection

We conducted a prospective single-centre cohort study of 104 multi-ethnic severe COVID-19 survivors from the first wave of the pandemic 15 months after hospitalisation. Of those who were assessed at 4 and 15 months, improvement of ground glass opacities correlated with worsened fibrotic reticulations. Despite a high prevalence of fibrotic patterns (64%), pulmonary function, grip strength, 6 min walk distance and frailty normalised. Overall, dyspnoea, cough and exhaustion did not improve and were not correlated with pulmonary function or radiographic fibrosis at 15 months, suggesting non-respiratory aetiologies. Monitoring persistent, and often subclinical, fibrotic interstitial abnormalities will be needed to determine their potential for future progression.

High-resolution Computed Tomography Thorax Volumetric Assessment in Coronavirus Disease 2019 Patients and Correlation with Pulmonary Function Tests

INTRODUCTION

Years after SARS coronavirus disease 2019 (COVID-19) recovery, residual pulmonary abnormalities may still exist. This brings on the question of whether or not COVID-19 could have comparable late consequences. Structural changes in the lungs after recovery can be better visualized using computed tomography (CT) thorax. Computed Tomography Lung Parenchymal changes during hospitalization by COVID-19 and after 4 months of follow-up to correlate with the volumetric high-resolution computed tomography thorax indices, Pulmonary function tests (PFTs) indices, SpO2, and 6 min Walking Test (6MWT).

MATERIALS AND METHODS

This is a Hospital based cross-sectional study, with a follow-up among 100 Patients from 2020 to 2022. Each patient's different CT parameters and HRCT volumetric indices Normal Lung (NL), Normal Lung Percentage (NL%), Whole Lung (WL) were correlated with the PFT indices (Forced expiratory volume in 1s [FEV1], forced vital capacity [FVC], FEV1/FVC), Oxygen Saturation (SpO2) and 6-Minute Walking Test (6MWT).

RESULTS

The mean NL (L) and NL% during COVID were significantly lower than the mean values 4 months post-COVID. Architectural distortion, bronchiolar dilatation, interstitial thickening, and parenchymal bands were reduced considerably after 4 months post-COVID, compared to during COVID. PFTs results, such as PFT indices, were not significantly different after 4 months post-COVID, compared to during COVID. SpO2 (%) and 6 MWT (m) were significantly increased. During COVID and post-COVID, the values of NL (L) and NL (%) had a significant positive correlation with PFT indices, SpO2, and 6MWT (m).

CONCLUSION

Hence, the different CT indices (NL and NL%) can be used as a surrogate for functional recovery of COVID patients since it correlates with the PFT indices (FEV1 and FEV1/FVC), SpO2, and 6MWT post-COVID.

Persistent pulmonary abnormalities after 18 months of SARS-CoV-2 pneumonia

OBJECTIVE

To describe persistent pulmonary abnormalities detected on HRCT after 18 months of SARS-CoV-2 pneumonia, and to determine their extension and correlation with pulmonary function.

PATIENTS AND METHODS

A prospective cross-sectional study with an initial cohort of 90 patients in follow-up due to persisting lung abnormalities on imaging, functional respiratory impairment and/or respiratory symptoms. Of these, 31 (34%) were selected for analysis due to the persistence of their lung abnormalities on HRCT at 18 months after infection. A double reading was performed for each HRCT (62 observations).

RESULTS

Of the 31 patients included: 20 (65%) were men; mean age was 67 years; 17 (55%) were smokers/ex-smokers. The mean hospitalisation time was 38 days. Eighteen (58%) patients were admitted to intensive care units. Five patients (16%) suffered an acute pulmonary thromboembolism and three (9.7%) had a pneumothorax. The mean time between the onset of pneumonia and the follow-up HRCT was 20.34 months. Nineteen percent of patients suffered from total lung function abnormalities; and ground-glass opacities and reticulation were present in 12% and 4.5% respectively. The findings of the 62 readings were: ground-glass opacities (100%), reticulation (83%), subpleural curvilinear lines (62%), parenchymal bands (34%), traction bronchiectasis (69%), displacement of vessels/fissures (46%) and honeycombing (4.9%). Pulmonary function 18 months after the acute episode revealed a mean FVC of 92% of predicted value, with an FVC < 80% of predicted value in 11 patients (35.4%). Mean DLCO was 71% of predicted value, with a DLCO < 80% in 22 patients (70%). We observed a statistically significant relationship between total lung function abnormalities on HRCT and FVC (P < 0.05), and a trend towards statistical significance with DLCO (P = 0.051); there was a statistically significant relationship between the presence of ground-glass opacities and FEV1/FVC (P < 0.01). The relationships between reticulation and FVC, FVC%, FEV1, FEV1% and DLCO% were also considered statistically significant (P < 0.05).

CONCLUSION

Persistent interstitial lung abnormalities are seen on HRCT for a subset of patients infected with SARS-CoV-2 pneumonia. Seventy percent of these patients suffered a slight decrease in DLCO.

Long-term outcome of pulmonary involvement in patients with coronavirus disease 2019: The role of high-resolution computed tomography and functional status - A prospective single-center observational study

BACKGROUND

Since its first outbreak, coronavirus disease 2019 (COVID-19) has led to a great deal of published literature highlighting the short-term determinants of morbidity and mortality. Recently, several studies have reported radiological and functional sequelae from 3 months to 1 year among hospitalized COVID-19 survivors; however, long-term (more than 1 year) respiratory consequences in this population remain to be evaluated.

OBJECTIVE

To assess the long-term radiological and pulmonary function outcomes of patients with COVID-19 2 years after resolution of the initial infection.

METHODS

Hospitalized COVID-19 patients with moderate to severe disease who survived acute illness were included in this prospective and partially retrospective study. Clinical assessment, laboratory tests, high-resolution computed tomography scans, and pulmonary function tests (PFTs) were performed at baseline, followed by radiological and lung function assessments at 6 and 24 months.

RESULTS

Among 106 enrolled participants (mean age 62 ± 13.5 years; males: 61), 44 (41.5%) and 27 (25.4%) underwent radiological assessment at 6 and 24 months, respectively. Overall, 22.6% (24) of patients had residual radiological abnormalities. Overt fibrosis was observed in 12.2% of patients. Computed tomography disease severity and extent diminished significantly at 6 (13 ± 6, P < 0.001) and 24 months (11 ± 6, P < 0.001) from baseline. PFTs were performed in 65 (61.3%), 22 (20.7%), and 34 (32%) patients at baseline, 6 and 24 months, respectively. Impaired diffusion capacity (median diffusion capacity for carbon monoxide: 60%, interquartile range [IQR]: 51-80), restrictive lung defect (mean total lung capacity: 73.4% ± 18% predicted), and reduced exercise tolerance (median 6-min walk distance: 360 m, IQR: 210-400) were the predominant features at baseline. With the exception of exercise tolerance, a statistically significant improvement was observed in lung function parameters at the extended follow-up (2 years).

CONCLUSIONS

Hospitalized COVID-19 survivors are at increased risk of developing long-term pulmonary complications, including lung fibrosis. A protocol-based approach to the management of post-COVID-19 patients is mandatory to improve future outcomes.

Quantitative CT Texture Analysis of COVID-19 Hospitalized Patients during 3-24-Month Follow-Up and Correlation with Functional Parameters

BACKGROUND

To quantitatively evaluate CT lung abnormalities in COVID-19 survivors from the acute phase to 24-month follow-up. Quantitative CT features as predictors of abnormalities' persistence were investigated.

METHODS

Patients who survived COVID-19 were retrospectively enrolled and underwent a chest CT at baseline (T0) and 3 months (T3) after discharge, with pulmonary function tests (PFTs). Patients with residual CT abnormalities repeated the CT at 12 (T12) and 24 (T24) months after discharge. A machine-learning-based software, CALIPER, calculated the CT percentage of the whole lung of normal parenchyma, ground glass (GG), reticulation (Ret), and vascular-related structures (VRSs). Differences (Δ) were calculated between time points. Receiver operating characteristic (ROC) curve analyses were performed to test the baseline parameters as predictors of functional impairment at T3 and of the persistence of CT abnormalities at T12.

RESULTS

The cohort included 128 patients at T0, 133 at T3, 61 at T12, and 34 at T24. The GG medians were 8.44%, 0.14%, 0.13% and 0.12% at T0, T3, T12 and T24. The Ret medians were 2.79% at T0 and 0.14% at the following time points. All Δ significantly differed from 0, except between T12 and T24. The GG and VRSs at T0 achieved AUCs of 0.73 as predictors of functional impairment, and area under the curves (AUCs) of 0.71 and 0.72 for the persistence of CT abnormalities at T12.

CONCLUSIONS

CALIPER accurately quantified the CT changes up to the 24-month follow-up. Resolution mostly occurred at T3, and Ret persisting at T12 was almost unchanged at T24. The baseline parameters were good predictors of functional impairment at T3 and of abnormalities' persistence at T12.

CT-based Assessment at 6-Month Follow-up of COVID-19 Pneumonia patients in China

This study aimed to assess pulmonary changes at 6-month follow-up CT and predictors of pulmonary residual abnormalities and fibrotic-like changes in COVID-19 pneumonia patients in China following relaxation of COVID restrictions in 2022. A total of 271 hospitalized patients with COVID-19 pneumonia admitted between November 29, 2022 and February 10, 2023 were prospectively evaluated at 6 months. CT characteristics and Chest CT scores of pulmonary abnormalities were compared between the initial and the 6-month CT. The association of demographic and clinical factors with CT residual abnormalities or fibrotic-like changes were assessed using logistic regression. Follow-up CT scans were obtained at a median of 177 days (IQR, 170-185 days) after hospital admission. Pulmonary residual abnormalities and fibrotic-like changes were found in 98 (36.2%) and 39 (14.4%) participants. In multivariable analysis of pulmonary residual abnormalities and fibrotic-like changes, the top three predictive factors were invasive ventilation (OR 13.6; 95% CI 1.9, 45; P < .001), age > 60 years (OR 9.1; 95% CI 2.3, 39; P = .01), paxlovid (OR 0.11; 95% CI 0.04, 0.48; P = .01) and invasive ventilation (OR 10.3; 95% CI 2.9, 33; P = .002), paxlovid (OR 0.1; 95% CI 0.03, 0.48; P = .01), smoker (OR 9.9; 95% CI 2.4, 31; P = .01), respectively. The 6-month follow-up CT of recent COVID-19 pneumonia cases in China showed a considerable proportion of the patients with pulmonary residual abnormalities and fibrotic-like changes. Antivirals against SARS-CoV-2 like paxlovid may be beneficial for long-term regression of COVID-19 pneumonia.

Unraveling Links between Chronic Inflammation and Long COVID: Workshop Report

As COVID-19 continues, an increasing number of patients develop long COVID symptoms varying in severity that last for weeks, months, or longer. Symptoms commonly include lingering loss of smell and taste, hearing loss, extreme fatigue, and "brain fog." Still, persistent cardiovascular and respiratory problems, muscle weakness, and neurologic issues have also been documented. A major problem is the lack of clear guidelines for diagnosing long COVID. Although some studies suggest that long COVID is due to prolonged inflammation after SARS-CoV-2 infection, the underlying mechanisms remain unclear. The broad range of COVID-19's bodily effects and responses after initial viral infection are also poorly understood. This workshop brought together multidisciplinary experts to showcase and discuss the latest research on long COVID and chronic inflammation that might be associated with the persistent sequelae following COVID-19 infection.

Radiological pulmonary sequelae after COVID-19 and correlation with clinical and functional pulmonary evaluation: results of a prospective cohort

OBJECTIVES

Whether COVID-19 leads to long-term pulmonary sequelae or not remains unknown. The aim of this study was to assess the prevalence of persisting radiological pulmonary fibrotic lesions in patients hospitalized for COVID-19.

MATERIALS AND METHODS

We conducted a prospective single-center study among patients hospitalized for COVID-19 between March and May 2020. Patients with residual symptoms or admitted into intensive care units were investigated 4 months after discharge by a chest CT (CCT) and pulmonary function tests (PFTs). The primary endpoint was the rate of persistent radiological fibrotic lesions after 4 months. Secondary endpoints included further CCT evaluation at 9 and 16 months, correlation of fibrotic lesions with clinical and PFT evaluation, and assessment of predictive factors.

RESULTS

Among the 1151 patients hospitalized for COVID-19, 169 patients performed a CCT at 4 months. CCTs showed pulmonary fibrotic lesions in 19% of the patients (32/169). These lesions were persistent at 9 months and 16 months in 97% (29/30) and 95% of patients (18/19) respectively. There was no significant clinical difference based on dyspnea scale in patients with pulmonary fibrosis. However, PFT evaluation showed significantly decreased diffusing lung capacity for carbon monoxide (p < 0.001) and total lung capacity (p < 0.001) in patients with radiological lesions. In multivariate analysis, the predictive factors of radiological pulmonary fibrotic lesions were pulmonary embolism (OR = 9.0), high-flow oxygen (OR = 6.37), and mechanical ventilation (OR = 3.49).

CONCLUSION

At 4 months, 19% of patients investigated after hospitalization for COVID-19 had radiological pulmonary fibrotic lesions; they persisted up to 16 months.

CLINICAL RELEVANCE STATEMENT

Whether COVID-19 leads to long-term pulmonary sequelae or not remains unknown. The aim of this study was to assess the prevalence of persisting radiological pulmonary fibrotic lesions in patients hospitalized for COVID-19. The prevalence of persisting lesions after COVID-19 remains unclear. We assessed this prevalence and predictive factors leading to fibrotic lesions in a large cohort. The respiratory clinical impact of these lesions was also assessed.

KEY POINTS

• Nineteen percent of patients hospitalized for COVID-19 had radiological fibrotic lesions at 4 months, remaining stable at 16 months. • COVID-19 fibrotic lesions did not match any infiltrative lung disease pattern. • COVID-19 fibrotic lesions were associated with pulmonary function test abnormalities but did not lead to clinical respiratory manifestation.

Chronic Lung Injury after COVID-19 Pneumonia: Clinical, Radiologic, and Histopathologic Perspectives

With the COVID-19 pandemic having lasted more than 3 years, concerns are growing about prolonged symptoms and respiratory complications in COVID-19 survivors, collectively termed post-COVID-19 condition (PCC). Up to 50% of patients have residual symptoms and physiologic impairment, particularly dyspnea and reduced diffusion capacity. Studies have also shown that 24%-54% of patients hospitalized during the 1st year of the pandemic exhibit radiologic abnormalities, such as ground-glass opacity, reticular opacity, bronchial dilatation, and air trapping, when imaged more than 1 year after infection. In patients with persistent respiratory symptoms but normal results at chest CT, dual-energy contrast-enhanced CT, xenon 129 MRI, and low-field-strength MRI were reported to show abnormal ventilation and/or perfusion, suggesting that some lung injury may not be detectable with standard CT. Histologic patterns in post-COVID-19 lung disease include fibrosis, organizing pneumonia, and vascular abnormality, indicating that different pathologic mechanisms may contribute to PCC. Therefore, a comprehensive imaging approach is necessary to evaluate and diagnose patients with persistent post-COVID-19 symptoms. This review will focus on the long-term findings of clinical and radiologic abnormalities and describe histopathologic perspectives. It also addresses advanced imaging techniques and deep learning approaches that can be applied to COVID-19 survivors. This field remains an active area of research, and further follow-up studies are warranted for a better understanding of the chronic stage of the disease and developing a multidisciplinary approach for patient management.

CT features of acute COVID-19 and long-term follow-up

Since the first few cases of pneumonia attributed to infection with the highly contagious novel coronavirus 2 (SARs-CoV-2) were detected in Wuhan, China, in December 2019, imaging has proven an invaluable diagnostic tool throughout the resulting global pandemic. This review describes the imaging features of severe pulmonary disease caused by SARs-CoV-2, named COVID-19 by the World Health Organization (WHO), particularly focussing on computed tomography (CT). CT plays an important role in understanding the pathology behind the progression of disease, as well as helping to identify the potential complications of COVID-19 pneumonia and recognising possible alternative or concurrent diagnoses. This review also focusses on follow-up imaging of survivors of COVID-19, which continues to contribute substantially to our understanding of the longer-term pulmonary changes in patients who have survived severe COVID-19 pneumonia.

Residual Lung Abnormalities in Survivors of Severe or Critical COVID-19 at One-Year Follow-Up Computed Tomography: A Narrative Review Comparing the European and East Asian Experiences

The literature reports that there was a significant difference in the medical impact of the coronavirus disease (COVID-19) pandemic between European and East Asian countries; specifically, the mortality rate of COVID-19 in Europe was significantly higher than that in East Asia. Considering such a difference, our narrative review aimed to compare the prevalence and characteristics of residual lung abnormalities at one-year follow-up computed tomography (CT) after severe or critical COVID-19 in survivors of European and East Asian countries. A literature search was performed to identify articles focusing on the prevalence and characteristics of CT lung abnormalities in survivors of severe or critical COVID-19. Database analysis identified 16 research articles, 9 from Europe and 7 from East Asia (all from China). Our analysis found a higher prevalence of CT lung abnormalities in European than in Chinese studies (82% vs. 52%). While the most prevalent lung abnormalities in Chinese studies were ground-glass opacities (35%), the most prevalent lung abnormalities in European studies were linear (59%) and reticular opacities (55%), followed by bronchiectasis (46%). Although our findings required confirmation, the higher prevalence and severity of lung abnormalities in European than in Chinese survivors of COVID-19 may reflect a greater architectural distortion due to a more severe lung damage.

The long-term effects of COVID-19 on pulmonary status and quality of life

Background

Few studies have looked at how SARS-CoV-2 affects pulmonary function, exercise capacity, and health-related quality of life over time. The purpose of this study was to evaluate these characteristics in post COVID-19 subjects 1 year after recovery.

Methods

The study included two groups. The case group included post COVID-19 subjects who had recovered after a year, and the control group included healthy participants who had never tested positive for COVID-19.

Results

The study screened 90 participants, 42 of whom met the eligibility criteria. The findings revealed that the majority of post COVID-19 subjects had relatively normal lung function 1-year post-recovery. A significant reduction in DLCO (B/P%) was observed in the case group vs. control. The exercise capacity test revealed a clinically significant difference in distance walked and a significant difference in the dyspnea post-walk test in the case group compared to the control group. The case group's health-related quality of life domain scores were significantly affected in terms of energy/fatigue, general health, and physical function.

Conclusions

The post COVID-19 subjects were shown to have well-preserved lung function after 1 year. However, some degree of impairment in diffusion capacity, exercise capacity, and health-related quality of life remained.

The long-term health outcomes, pathophysiological mechanisms and multidisciplinary management of long COVID

There have been hundreds of millions of cases of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the growing population of recovered patients, it is crucial to understand the long-term consequences of the disease and management strategies. Although COVID-19 was initially considered an acute respiratory illness, recent evidence suggests that manifestations including but not limited to those of the cardiovascular, respiratory, neuropsychiatric, gastrointestinal, reproductive, and musculoskeletal systems may persist long after the acute phase. These persistent manifestations, also referred to as long COVID, could impact all patients with COVID-19 across the full spectrum of illness severity. Herein, we comprehensively review the current literature on long COVID, highlighting its epidemiological understanding, the impact of vaccinations, organ-specific sequelae, pathophysiological mechanisms, and multidisciplinary management strategies. In addition, the impact of psychological and psychosomatic factors is also underscored. Despite these crucial findings on long COVID, the current diagnostic and therapeutic strategies based on previous experience and pilot studies remain inadequate, and well-designed clinical trials should be prioritized to validate existing hypotheses. Thus, we propose the primary challenges concerning biological knowledge gaps and efficient remedies as well as discuss the corresponding recommendations.

Impact of COVID infection on lung function test and quality of life

Post-COVID-19 pulmonary sequalae are well-recognized early in the pandemic. Survivorship clinics are crucial for managing at-risk patients. However, it is unclear who requires pulmonary function test (PFT) and when PFTs should be performed. We aim to investigate for whom and how these interval PFTs should be performed. We performed a single-centre, prospective cohort study on COVID-19 survivors between 1st May 2020 and 31st April 2022. These patients were followed up at 6, 9 and 12 months with interval PFT and Short Form-36 (SF-36) Health Survey. Those with PFT defects were offered a computed tomography scan of the thorax. Of the 46 patients recruited, 17 (37%) had severe/critical illness. Compared to those with mild/moderate disease, these patients were more likely to experience DLCO defects (59% versus 17%, p = 0.005) and had lower SF-36 scores (mean physical component summary score of 45 ± 12 versus 52 ± 8, p = 0.046). These differences were most notable at 6 months, compared to the 9- and 12-months intervals. DLCO defects were also associated with older age, raised inflammatory markers and extensive CXR infiltrates. Besides interstitial-like abnormalities, obesity and undiagnosed lung conditions accounted for 39% of the PFT abnormalities. Interval PFTs can be performed earliest 6 months post-COVID-19. Patients with normal tests were unlikely to develop new abnormalities and would not require repeat PFTs. Abnormal PFTs can be followed-up with repeat PFTs 6 monthly until resolution. Non-COVID-19 differentials should be considered for persistent PFT abnormalities.

Algorithmic approach in the management of COVID-19 patients with residual pulmonary symptoms

Coronavirus-19 emerged about 3 years ago and has proven to be a devastating disease, crippling communities worldwide and accounting for more than 6.31 million deaths. The true disease burden of COVID-19 will come to light in the upcoming years as we care for COVID-19 survivors with post-COVID-19 syndrome (PCS) with residual long-term symptoms affecting every organ system. Pulmonary fibrosis is the most severe long-term pulmonary manifestation of PCS, and due to the high incidence of COVID-19 infection rates, PCS-pulmonary fibrosis has the potential of becoming the next large-scale respiratory health crisis. To confront the potentially devastating effects of emerging post-COVID-19 pulmonary fibrosis, dedicated research efforts are needed to focus on surveillance, understanding pathophysiologic mechanisms, and most importantly, an algorithmic approach to managing these patients. We have performed a thorough literature review on post-COVID-19 pulmonary symptoms/imaging/physiology and present an algorithmic approach to these patients based on the best available data and extensive clinical experience.

Post-COVID-19 dyspnoea and pulmonary imaging: a systematic review and meta-analysis

BACKGROUND

A proportion of coronavirus disease 2019 (COVID-19) survivors experience persistent dyspnoea without measurable impairments in lung function. We performed a systematic review and meta-analysis to determine relationships between dyspnoea and imaging abnormalities over time in post-COVID-19 patients.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we analysed studies published prior to 15 September 2022 and indexed by Google Scholar, PubMed and LitCOVID which assessed chest imaging in adults ≥3 months after COVID-19. Demographic, chest imaging, spirometric and post-COVID-19 symptom data were extracted. The relationships between imaging abnormalities and dyspnoea, sex and age were determined using a random effects model and meta-regression.

RESULTS

47 studies were included in the meta-analysis (n=3557). The most prevalent computed tomography (CT) imaging abnormality was ground-glass opacities (GGOs) (44.9% (95% CI 37.0-52.9%) at any follow-up time-point). Occurrence of reticulations significantly decreased between early and late follow-up (p=0.01). The prevalence of imaging abnormalities was related to the proportion of patients with dyspnoea (p=0.012). The proportion of females was negatively correlated with the presence of reticulations (p=0.001), bronchiectasis (p=0.001) and consolidations (p=0.025). Age was positively correlated with imaging abnormalities across all modalities (p=0.002) and imaging abnormalities present only on CT (p=0.001) (GGOs (p=0.004) and reticulations (p=0.001)). Spirometric values improved during follow-up but remained within the normal range at all time-points.

CONCLUSIONS

Imaging abnormalities were common 3 months after COVID-19 and their occurrence was significantly related to the presence of dyspnoea. This suggests that CT imaging is a sensitive tool for detecting pulmonary abnormalities in patients with dyspnoea, even in the presence of normal spirometric measurements.

Chest CT features and functional correlates of COVID-19 at 3 months and 12 months follow-up

Long-term pulmonary sequelae of Coronavirus 2019 (COVID-19) remain unclear. Thus, we aimed to establish post-COVID-19 temporal changes in chest computed tomography (CT) features of pulmonary fibrosis and to investigate associations with respiratory symptoms and physiological parameters at 3 and 12 months' follow-up. Adult patients who attended our initial COVID-19 follow-up service and developed chest CT features of interstitial lung disease, in addition to cases identified using British Society of Thoracic Imaging codes, were evaluated retrospectively. Clinical data were gathered on respiratory symptoms and physiological parameters at baseline, 3 months, and 12 months. Corresponding chest CT scans were reviewed by two thoracic radiologists. Associations between CT features and functional correlates were estimated using random effects logistic or linear regression adjusted for age, sex and body mass index. In total, 58 patients were assessed. No changes in reticular pattern, honeycombing, traction bronchiectasis/bronchiolectasis index or pulmonary distortion were observed. Subpleural curvilinear lines were associated with lower odds of breathlessness over time. Parenchymal bands were not associated with breathlessness or impaired lung function overall. Based on our results, we conclude that post-COVID-19 chest CT features of irreversible pulmonary fibrosis remain static over time; other features either resolve or remain unchanged. Subpleural curvilinear lines do not correlate with breathlessness. Parenchymal bands are not functionally significant. An awareness of the different potential functional implications of post-COVID-19 chest CT changes is important in the assessment of patients who present with multi-systemic sequelae of COVID-19 infection.

COVID-19 and interstitial lung diseases: A multifaceted look at the relationship between the two diseases

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although it has been a fatal disease for many patients, the development of treatment strategies and vaccines have progressed over the past 3 years, and our society has become able to accept COVID-19 as a manageable common disease. However, as COVID-19 sometimes causes pneumonia, post-COVID pulmonary fibrosis (PCPF), and worsening of preexisting interstitial lung diseases (ILDs), it is still a concern for pulmonary physicians. In this review, we have selected several topics regarding the relationships between ILDs and COVID-19. The pathogenesis of COVID-19-induced ILD is currently assumed based mainly on the evidence of other ILDs and has not been well elucidated specifically in the context of COVID-19. We have summarized what has been clarified to date and constructed a coherent story about the establishment and progress of the disease. We have also reviewed clinical information regarding ILDs newly induced or worsened by COVID-19 or anti-SARS-CoV-2 vaccines. Inflammatory and profibrotic responses induced by COVID-19 or vaccines have been thought to be a risk for de novo induction or worsening of ILDs, and this has been supported by the evidence obtained through clinical experience over the past 3 years. Although COVID-19 has become a mild disease in most cases, it is still worth looking back on the above-reviewed information to broaden our perspectives regarding the relationship between viral infection and ILD. As a representative etiology for severe viral pneumonia, further studies in this area are expected.

Biomarkers of Fibrosis in Patients with COVID-19 One Year After Hospital Discharge: A Prospective Cohort Study

Beyond the acute infection of coronavirus disease (COVID-19), concern has arisen about long-term effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The aim of our study was to analyze if there is any biomarker of fibrogenesis in patients with COVID-19 pneumonia capable of predicting post-COVID-19 pulmonary sequelae. We conducted a multicenter, prospective, observational cohort study of patients admitted to a hospital with bilateral COVID-19 pneumonia. We classified patients into two groups according to severity, and blood sampling to measure matrix metalloproteinase 1 (MMP-1), MMP-7, periostin, and VEGF and respiratory function tests and high-resolution computed tomography were performed at 2 and 12 months after hospital discharge. A total of 135 patients were evaluated at 12 months. Their median age was 61 (interquartile range, 19) years, and 58.5% were men. We found between-group differences in age, radiological involvement, length of hospital stay, and inflammatory laboratory parameters. Differences were found between 2 and 12 months in all functional tests, including improvements in predicted forced vital capacity (98.0% vs. 103.9%; P = 0.001) and DlCO <80% (60.9% vs. 39.7%; P = 0.001). At 12 months, 63% of patients had complete high-resolution computed tomography resolution, but fibrotic changes persisted in 29.4%. Biomarker analysis demonstrated differences at 2 months in periostin (0.8893 vs. 1.437 ng/ml; P < 0.001) and MMP-7 (8.7249 vs. 15.2181 ng/ml; P < 0.001). No differences were found at 12 months. In multivariable analysis, only 2-month periostin was associated with 12-month fibrotic changes (odds ratio, 1.0013; 95% confidence interval, 1.0006-1.00231; P = 0.003) and 12-month DlCO impairment (odds ratio, 1.0006; 95% confidence interval, 1.0000-1.0013; P = 0.047). Our data suggest that early periostin postdischarge could predict the presence of fibrotic pulmonary changes.

Twelve-month follow-up after hospitalization for SARS-COV-2: Physiology improves, symptoms remain

OBJECTIVES

Persistent symptoms on short-term follow-up after infection with COVID-19 are common, but long-term consequences have been insufficiently studied. The aim of this study was to characterize pulmonary function and ongoing symptoms 12 months after hospitalization with COVID-19.

METHODS

This prospective multicenter study included 222 patients hospitalized with PCR-confirmed COVID-19 in the Central Denmark Region. Disease severity was stratified using WHO Clinical Progression Scale. Clinical characteristics, pulmonary function test (PFT), 6-minute walk test (6MWT), and patient-reported outcome measures were collected at follow-up 3 and 12 months after discharge. Outcome measures from follow-up 3 months after discharge have previously been published.

RESULTS

A total of 179 (81%) patients completed the 12-month follow-up. Median age was 60 years (IQR 51, 69) and 58% were male patients. At 12-month follow-up 49.7% had a normal diffusion capacity for carbon monoxide (DLCO), while 39.4% had DLCO < 80%. The 6MWT distance increased significantly (29 m 95% CI 19, 40; p < 0.01). An mMRC score of 0 was reported by 51% and an mMRC ≥ 2 by 20%. The frequency and severity of fatigue, depression, and anxiety did not improve over time.

CONCLUSIONS

The study found that impaired DLCO percentage is common 12 months after hospitalization with SARS-CoV-2 and reduction in DLCO percentage is associated to dyspnea.

The added value of lung perfusion scintigraphy semiquantitative measures in post-COVID patients with persistent dyspnea without pulmonary embolism

BACKGROUND

Persistent dyspnea is frequent in post-COVID patients, even in the absence of pulmonary embolism (PE). In this scenario, the role of lung perfusion scintigraphy is unclear. The present study correlated scintigraphy-based semiquantitative perfusion parameters with chest high-resolution computed tomography (hrCT) volumetric indexes and clinical data in post-COVID patients with persistent dyspnea.

RESEARCH DESIGN AND METHODS

Sixty patients (30 post-COVID and 30 not previously affected by COVID-19) with persistent dyspnea submitted to lung perfusion scintigraphy and hrCT were retrospectively recruited. Perfusion rates of the pulmonary fields and hrCT-based normalized inflated, emphysematous, infiltrated, collapsed, and vascular lung volumes were calculated. Inflammatory and coagulation biomarkers were collected. PE at imaging was an exclusion criterion.

RESULTS

Compared to controls, reduced perfusion rates of the lower pulmonary fields and higher perfusion rates of the middle ones were observed in post-COVID patients, while hrCT findings were superimposable between the two groups. Perfusion rates of lower pulmonary fields were significantly associated only with abnormal lung volumes at hrCT.

CONCLUSIONS

In post-COVID dyspnea without PE, lung perfusion scintigraphy may reveal a pulmonary involvement not detectable by hrCT. Post-COVID patients may show decreased perfusion rates of lower pulmonary fields in the presence of normal vascular density and markers of inflammation/coagulation.

Quantitative Evaluation of COVID-19 Pneumonia CT Using AI Analysis-Feasibility and Differentiation from Other Common Pneumonia Forms

PURPOSE: To implement the technical feasibility of an AI-based software prototype optimized for the detection of COVID-19 pneumonia in CT datasets of the lung and the differentiation between other etiologies of pneumonia. METHODS: This single-center retrospective case-control-study consecutively yielded 144 patients (58 female, mean age 57.72 ± 18.25 y) with CT datasets of the lung. Subgroups including confirmed bacterial (n = 24, 16.6%), viral (n = 52, 36.1%), or fungal (n = 25, 16.6%) pneumonia and (n = 43, 30.7%) patients without detected pneumonia (comparison group) were evaluated using the AI-based Pneumonia Analysis prototype. Scoring (extent, etiology) was compared to reader assessment. RESULTS: The software achieved an optimal sensitivity of 80.8% with a specificity of 50% for the detection of COVID-19; however, the human radiologist achieved optimal sensitivity of 80.8% and a specificity of 97.2%. The mean postprocessing time was 7.61 ± 4.22 min. The use of a contrast agent did not influence the results of the software (p = 0.81). The mean evaluated COVID-19 probability is 0.80 ± 0.36 significantly higher in COVID-19 patients than in patients with fungal pneumonia (p < 0.05) and bacterial pneumonia (p < 0.001). The mean percentage of opacity (PO) and percentage of high opacity (PHO ≥ -200 HU) were significantly higher in COVID-19 patients than in healthy patients. However, the total mean HU in COVID-19 patients was -679.57 ± 112.72, which is significantly higher than in the healthy control group (p < 0.001). CONCLUSION: The detection and quantification of pneumonia beyond the primarily trained COVID-19 datasets is possible and shows comparable results for COVID-19 pneumonia to an experienced reader. The advantages are the fast, automated segmentation and quantification of the pneumonia foci.

Clinicopathological Outlines of Post-COVID-19 Pulmonary Fibrosis Compared with Idiopathic Pulmonary Fibrosis

This review brings together the current knowledge regarding the risk factors and the clinical, radiologic, and histological features of both post-COVID-19 pulmonary fibrosis (PCPF) and idiopathic pulmonary fibrosis (IPF), describing the similarities and the disparities between these two diseases, using numerous databases to identify relevant articles published in English through October 2022. This review would help clinicians, pathologists, and researchers make an accurate diagnosis, which can help identify the group of patients selected for anti-fibrotic therapies and future therapeutic perspectives.

Interpretation of chest radiography in patients with known or suspected SARS-CoV-2 infection: what we learnt from comparison with computed tomography

Differently from computed tomography (CT), well-defined terminology for chest radiography (CXR) findings and standardized reporting in the setting of known or suspected COVID-19 are still lacking. We propose a revision of CXR major imaging findings in SARS-CoV-2 pneumonia derived from the comparison of CXR and CT, suggesting a precise and standardized terminology for CXR reporting. This description will consider asymptomatic patients, symptomatic patients, and patients with SARS-CoV-2-related pulmonary complications. We suggest using terms such as ground-glass opacities, consolidation, and reticular pattern for the most common findings, and characteristic chest radiographic pattern in presence of one or more of the above-mentioned findings with peripheral and mid-to-lower lung zone distribution.

Role of the one-minute sit-to-stand test in the diagnosis of post COVID-19 condition: a prospective cohort study

OBJECTIVE

To analyze the relationship between one-minute sit-to-stand test (1MSTST) parameters and a diagnosis of post COVID-19 condition in a cohort of patients who previously had COVID-19.

METHODS

This was a prospective cohort study of patients with post COVID-19 condition referred for body plethysmography at a tertiary university hospital. Post COVID-19 condition was defined in accordance with the current WHO criteria.

RESULTS

Fifty-three patients were analyzed. Of those, 25 (47.2%) met the clinical criteria for post COVID-19 condition. HR was lower in the patients with post COVID-19 condition than in those without it at 30 s after initiation of the 1MSTST (86.2 ± 14.3 bpm vs. 101.2 ± 14.7 bpm; p < 0.001) and at the end of the test (94.4 ± 18.2 bpm vs. 117.3 ± 15.3 bpm; p < 0.001). The ratio between HR at the end of the 1MSTST and age-predicted maximal HR (HRend/HRmax) was lower in the group of patients with post COVID-19 condition (p < 0.001). An HRend/HRmax of < 62.65% showed a sensitivity of 78.6% and a specificity of 82.0% for post COVID-19 condition. Mean SpO2 at the end of the 1MSTST was lower in the patients with post COVID-19 condition than in those without it (94.9 ± 3.6% vs. 96.8 ± 2.4%; p = 0.030). The former group of patients did fewer repetitions on the 1MSTST than did the latter (p = 0.020).

CONCLUSIONS

Lower SpO2 and HR at the end of the 1MSTST, as well as lower HR at 30 s after initiation of the test, were associated with post COVID-19 condition. In the appropriate clinical setting, an HRend/HRmax of < 62.65% should raise awareness for the possibility of post COVID-19 condition.

Post-COVID-19 Pulmonary Alveolar Proteinosis Treated Successfully with Whole Lung Lavage: A Rare Case Report

Pulmonary alveolar proteinosis (PAP) is an uncommon disease and its diagnosis remains challenging. During the COVID-19 pandemic, it has been difficult to distinguish between PAP and post-COVID-19 pulmonary sequelae. Here we present a case of a 44-year-old male patient who experienced exertional dyspnea after recovering from COVID-19. He was initially diagnosed with post-COVID-19 syndrome and treated with systemic corticosteroid without improvement. Chest computed tomography (CT) showed crazy-paving pattern with ground-glass opacities. Fibreoptic bronchoscopy with bronchial lavage fluid (BLF) analysis confirmed the final diagnosis of PAP. The patient underwent left lung lavage in combination with conventional therapy and experienced significant improvement in his respiratory condition and overall health during follow-up. Hence, PAP could occur after a COVID-19 infection. This case highlights the importance of considering PAP as a potential diagnosis in patients with persistent respiratory symptoms after COVID-19. The high suspicion indicators of PAP revealed by chest-CT and BLF may be a key to differentiating PAP from post-COVID-19 pulmonary sequelae. Moreover, it is plausible that SARS-CoV-2 plays a role in the development of proteinosis, either by inducing a flare-up or by directly causing the condition.

COVID-19: Findings in nuclear medicine from head to toe

COVID-19 is a multisystemic disease, and hence its potential manifestations on nuclear medicine imaging can extend beyond the lung. Therefore, it is important for the nuclear medicine physician to recognize these manifestations in the clinic. While FDG-PET/CT is not indicated routinely in COVID-19 evaluation, its unique capability to provide a functional and anatomical assessment of the entire body means that it can be a powerful tool to monitor acute, subacute, and long-term effects of COVID-19. Single-photon scintigraphy is routinely used to assess conditions such as pulmonary embolism, cardiac ischemia, and thyroiditis, and COVID-19 may present in these studies. The most common nuclear imaging finding of COVID-19 vaccination to date is hypermetabolic axillary lymphadenopathy. This may pose important diagnostic and management dilemmas in oncologic patients, particularly those with malignancies where the axilla constitutes a lymphatic drainage area. This article aims to summarize the relevant literature published since the beginning of the pandemic on the intersection between COVID-19 and nuclear medicine.

Lung ultrasound as a tool for monitoring the interstitial changes in recently hospitalised patients with COVID-19 pneumonia - The COVIDLUS study

Background Long-term respiratory effects can occur after COVID-19 pneumonia (CP). The COVID Lung Ultrasound Study (COVIDLUS) aimed to investigate the utility of serial lung ultrasound (LUS) to track functional and physiological recovery after hospitalisation in patients with CP. Methods Between April 2021 and April 2022, 21 patients were recruited at discharge (D0). LUS was performed on D0, day 41 (D41) and day 83 (D83). CT Thorax was performed on D83. Lymphocyte count, Ferritin, Lactate Dehydrogenase, Troponin, CRP, and D-dimers were measured at D0, D41 and D83. 6 minute walking test (6MWT) was performed on D83 and quality of life questionnaires and spirometry completed on D41 and D83. Results 19 subjects completed the study (10 males [52%]; mean age: 52 years [range:37-74]). 1 patient died. LUS scores were significantly higher at D0, compared to D41 and D83 (Mean score:10.9 [D0]/2.8 [D41]/1.5 [D83]; p < 0.0001). LUS scores correlated poorly with CT at D83 (Pearson r² = 0.28). Mean lymphocyte counts were lower at D0 but increased at D41 and D83. Mean serum Ferritin was significantly lower at D41 and D83, as compared to D0. The mean 6MWT distance was 385 m (130-540 m). Quality of life measures did not differ at D41 and D83. Lung function increased between D41 and D83 with mean increase in FEV₁ and FVC of 160 ml and 190 ml respectively. Conclusion LUS can monitor the early recovery of lung interstitial changes from CP. The utility of LUS to predict development of subsequent lung fibrosis post-COVID deserves further study.

Detection of Post-COVID-19 Lung Abnormalities: Photon-counting CT versus Same-Day Energy-integrating Detector CT

Background Photon-counting detector (PCD) CT enables ultra-high-resolution lung imaging and may shed light on morphologic correlates of persistent symptoms after COVID-19. Purpose To compare PCD CT with energy-integrating detector (EID) CT for noninvasive assessment of post-COVID-19 lung abnormalities. Materials and Methods For this prospective study, adult participants with one or more COVID-19-related persisting symptoms (resting or exertional dyspnea, cough, fatigue) underwent same-day EID and PCD CT between April 2022 and June 2022. The 1.0-mm EID CT images and, subsequently, 1.0-, 0.4-, and 0.2-mm PCD CT images were reviewed for the presence of lung abnormalities. Subjective and objective EID and PCD CT image quality were evaluated using a five-point Likert scale (-2 to 2) and lung signal-to-noise ratios (SNRs). Results Twenty participants (mean age, 54 years ± 16 [SD]; 10 men) were included. EID CT showed post-COVID-19 lung abnormalities in 15 of 20 (75%) participants, with a median involvement of 10% of lung volume [IQR, 0%-45%] and 3.5 lobes [IQR, 0-5]. Ground-glass opacities and linear bands (10 of 20 participants [50%] for both) were the most frequent findings at EID CT. PCD CT revealed additional lung abnormalities in 10 of 20 (50%) participants, with the most common being bronchiectasis (10 of 20 [50%]). Subjective image quality was improved for 1.0-mm PCD versus 1.0-mm EID CT images (median, 1; IQR, 1-2; P < .001) and 0.4-mm versus 1.0-mm PCD CT images (median, 1; IQR, 1-1; P < .001) but not for 0.4-mm versus 0.2-mm PCD CT images (median, 0; IQR, 0-0.5; P = .26). PCD CT delivered higher lung SNR versus EID CT for 1.0-mm images (mean difference, 0.53 ± 0.96; P = .03) but lower SNR for 0.4-mm versus 1.0-mm images and 0.2-mm vs 0.4-mm images (-1.52 ± 0.68 [P < .001] and -1.15 ± 0.43 [P < .001], respectively). Conclusion Photon-counting detector CT outperformed energy-integrating detector CT in the visualization of subtle post-COVID-19 lung abnormalities and image quality. © RSNA, 2023 Supplemental material is available for this article.

Lowered oxygen saturation and increased body temperature in acute COVID-19 largely predict chronic fatigue syndrome and affective symptoms due to Long COVID: A precision nomothetic approach

BACKGROUND

Long coronavirus disease 2019 (LC) is a chronic sequel of acute COVID-19. The exact pathophysiology of the affective, chronic fatigue and physiosomatic symptoms (labelled as "physio-affective phenome") of LC has remained elusive.

OBJECTIVE

The current study aims to delineate the effects of oxygen saturation (SpO2) and body temperature during the acute phase on the physio-affective phenome of LC.

METHOD

We recruited 120 LC patients and 36 controls. For all participants, we assessed the lowest SpO2 and peak body temperature during acute COVID-19, and the Hamilton Depression and Anxiety Rating Scale (HAMD/HAMA) and Fibro Fatigue (FF) scales 3-4 months later.

RESULTS

Lowered SpO2 and increased body temperature during the acute phase and female sex predict 60.7% of the variance in the physio-affective phenome of LC. Using unsupervised learning techniques, we were able to delineate a new endophenotype class, which comprises around 26.7% of the LC patients and is characterised by very low SpO2 and very high body temperature, and depression, anxiety, chronic fatigue, and autonomic and gastro-intestinal symptoms scores. Single latent vectors could be extracted from both biomarkers, depression, anxiety and FF symptoms or from both biomarkers, insomnia, chronic fatigue, gastro-intestinal and autonomic symptoms.

CONCLUSION

The newly constructed endophenotype class and pathway phenotypes indicate that the physio-affective phenome of LC is at least in part the consequence of the pathophysiology of acute COVID-19, namely the combined effects of lowered SpO2, increased body temperature and the associated immune-inflammatory processes and lung lesions.

Cardiopulmonary Outcomes in Covid-19 Patients Discharged From a Tertiary Care Center: A Prospective Study

To determine the cardiopulmonary changes in the survivors of acute COVID-19 infection at 3-6 month and 6-12 month. We followed up 53 patients out of which 28 (52%) had mild COVID-19 and 25 (48%) had severe COVID-19. The first follow-up was between 3 month after diagnosis up to 6 month and second follow-up between 6 and 12 month from the date of diagnosis of acute COVID-19. They were monitored using vital parameters, pulmonary function tests, echocardiography and a chest computed tomography (CT) scan. We found improvement in diffusing capacity for carbon monoxide (DLCO) with a median of 52% of predicted and 80% of predicted at the first and second follow-up, respectively. There was improvement in the CTSS in severe group from 22 (18-24) to 12 (10-18; p-0.001). Multivariable logistic regression revealed increased odds of past severe disease with higher CTSS at follow-up (OR-1.7 [CI 1.14-2.77]; P = 0.01). Correlation was found between CTSS and DLCO at second follow-up (r2 = 0.36; p < 0.01). Most of patients recovered from COVID-19 but a subgroup of patients continued to have persistent radiological and pulmonary function abnormalities necessitating a structured follow-up.

Severe COVID-19 pneumonia leads to post-COVID-19 lung abnormalities on follow-up CT scans

Purpose

To investigate the association of the maximal severity of pneumonia on CT scans obtained within 6-week of diagnosis with the subsequent development of post-COVID-19 lung abnormalities (Co-LA).

Methods

COVID-19 patients diagnosed at our hospital between March 2020 and September 2021 were studied retrospectively. The patients were included if they had (1) at least one chest CT scan available within 6-week of diagnosis; and (2) at least one follow-up chest CT scan available ≥ 6 months after diagnosis, which were evaluated by two independent radiologists. Pneumonia Severity Categories were assigned on CT at diagnosis according to the CT patterns of pneumonia and extent as: 1) no pneumonia (Estimated Extent, 0%); 2) non-extensive pneumonia (GGO and OP, <40%); and 3) extensive pneumonia (extensive OP and DAD, >40%). Co-LA on follow-up CT scans, categorized using a 3-point Co-LA Score (0, No Co-LA; 1, Indeterminate Co-LA; and 2, Co-LA).

Results

Out of 132 patients, 42 patients (32%) developed Co-LA on their follow-up CT scans 6-24 months post diagnosis. The severity of COVID-19 pneumonia was associated with Co-LA: In 47 patients with extensive pneumonia, 33 patients (70%) developed Co-LA, of whom 18 (55%) developed fibrotic Co-LA. In 52 with non-extensive pneumonia, 9 (17%) developed Co-LA: In 33 with no pneumonia, none (0%) developed Co-LA.

Conclusions

Higher severity of pneumonia at diagnosis was associated with the increased risk of development of Co-LA after 6-24 months of SARS-CoV-2 infection.

Lung fibrosis: Post-COVID-19 complications and evidences

BACKGROUND

COVID 19, a lethal viral outbreak that devastated lives and the economy across the globe witnessed non-compensable respiratory illnesses in patients. As been evaluated in reports, patients receiving long-term treatment are more prone to acquire Pulmonary Fibrosis (PF). Repetitive damage and repair of alveolar tissues increase oxidative stress, inflammation and elevated production of fibrotic proteins ultimately disrupting normal lung physiology skewing the balance towards the fibrotic milieu.

AIM

In the present work, we have discussed several important pathways which are involved in post-COVID PF. Further, we have also highlighted the rationale for the use of antifibrotic agents for post-COVID PF to decrease the burden and improve pulmonary functions in COVID-19 patients.

CONCLUSION

Based on the available literature and recent incidences, it is crucial to monitor COVID-19 patients over a period of time to rule out the possibility of residual effects. There is a need for concrete evidence to deeply understand the mechanisms responsible for PF in COVID-19 patients.

The Risk Factors and Outcomes for Radiological Abnormalities in Early Convalescence of COVID-19 Patients Caused by the SARS-CoV-2 Omicron Variant: A Retrospective, Multicenter Follow-up Study

BACKGROUND

The emergence of the severe acute respiratory syndrome coronavirus 2 omicron variant has been triggering the new wave of coronavirus disease 2019 (COVID-19) globally. However, the risk factors and outcomes for radiological abnormalities in the early convalescent stage (1 month after diagnosis) of omicron infected patients are still unknown.

METHODS

Patients were retrospectively enrolled if they were admitted to the hospital due to COVID-19. The chest computed tomography (CT) images and clinical data obtained at baseline (at the time of the first CT image that showed abnormalities after diagnosis) and 1 month after diagnosis were longitudinally analyzed. Uni-/multi-variable logistic regression tests were performed to explore independent risk factors for radiological abnormalities at baseline and residual pulmonary abnormalities after 1 month.

RESULTS

We assessed 316 COVID-19 patients, including 47% with radiological abnormalities at baseline and 23% with residual pulmonary abnormalities at 1-month follow-up. In a multivariate regression analysis, age ≥ 50 years, body mass index ≥ 23.87, days after vaccination ≥ 81 days, lymphocyte count ≤ 1.21 × 10^-9/L, interleukin-6 (IL-6) ≥ 10.05 pg/mL and IgG ≤ 14.140 S/CO were independent risk factors for CT abnormalities at baseline. The age ≥ 47 years, presence of interlobular septal thickening and IL-6 ≥ 5.85 pg/mL were the independent risk factors for residual pulmonary abnormalities at 1-month follow-up. For residual abnormalities group, the patients with less consolidations and more parenchymal bands at baseline could progress on CT score after 1 month. There were no significant changes in the number of involved lung lobes and total CT score during the early convalescent stage.

CONCLUSION

The higher IL-6 level was a common independent risk factor for CT abnormalities at baseline and residual pulmonary abnormalities at 1-month follow-up. There were no obvious radiographic changes during the early convalescent stage in patients with residual pulmonary abnormalities.

Longitudinal Assessment of Chest CT Findings and Pulmonary Function in Patients after COVID-19

Background Information on pulmonary sequelae and pulmonary function at 2 years post recovery from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are lacking. Purpose To longitudinally assess changes in chest CT abnormities and pulmonary function in patients after SARS-CoV-2 infection. Materials and Methods In this prospective study, patients discharged from the hospital after SARS-CoV-2 infection between January 15 and March 10, 2020 were considered for enrollment. Patients without chest CT scans on admission or with complete resolution of lung abnormities on discharge were excluded. Three serial chest CT scans and pulmonary function tests were obtained at 6 months (June 20-August 31, 2020), 12 months (December 20, 2020-February 3, 2021), and 2 years (November 16, 2021-January 10, 2022) after symptom onset. The term interstitial lung abnormalities (ILAs) and two subcategories, fibrotic ILAs and non-fibrotic ILAs, were used to describe the residual CT abnormalities on follow-up CT scans. Differences between groups were compared with χ², Fisher's exact test, or independent-samples t-test. Results Totally, 144 participants (median age, 60 [ranges 27-80] years; 79 men and 65 women) were included. On 2-year follow-up CT scans, 39% (56/144) of the subjects presented with ILAs, including 23% (33/144) wi fibrotic ILAs and 16% (23/144) with non-fibrotic ILAs. The remaining 88 cases (61%) showed complete radiological resolution. Over 2 years, the incidence of ILAs gradually decreased (54%, 42% and 39% at 6 months, 12 months and 2 years, respectively; P = .001). Respiratory symptoms (34% vs 15%, P =.007) and abnormal diffusing capacity of the lung for carbon monoxide (DLco,43% vs 20%, P = .004) more frequently occurred in participants with ILAs than those with complete radiological resolution. Conclusions More than one third of participants had persistent interstitial lung abnormalities at 2 years, which were associated with respiratory symptoms and decreased diffusion pulmonary function. See also the editorial by van Beek in this issue.

Current and Emerging Knowledge in COVID-19

COVID-19 has emerged as a pandemic leading to a global public health crisis of unprecedented morbidity. A comprehensive insight into the imaging of COVID-19 has enabled early diagnosis, stratification of disease severity, and identification of potential sequelae. The evolution of COVID-19 can be divided into early infectious, pulmonary, and hyperinflammatory phases. Clinical features, imaging features, and management are different among the three phases. In the early stage, peripheral ground-glass opacities are predominant CT findings, and therapy directly targeting SARS-CoV-2 is effective. In the later stage, organizing pneumonia or diffuse alveolar damage pattern are predominant CT findings and anti-inflammatory therapies are more beneficial. The risk of severe disease or hospitalization is lower in breakthrough or Omicron variant infection compared with nonimmunized or Delta variant infections. The protection rates of the fourth dose of mRNA vaccination were 34% and 67% against overall infection and hospitalizations for severe illness, respectively. After acute COVID-19 pneumonia, most residual CT abnormalities gradually decreased in extent, but they may remain as linear or multifocal reticular or cystic lesions. Advanced insights into the pathophysiologic and imaging features of COVID-19 along with vaccine benefits have improved patient care, but emerging knowledge of post-COVID-19 condition, or long COVID, also presents radiology with new challenges.

Pulmonary Function Test as a Diagnostic Tool for Post-COVID-19 Effects

COVID-19-infected survivors are reporting persistent anomalies upon hospital discharge. After one year, a sizable percentage of COVID-19 survivors still have persistent symptoms affecting different bodily systems. Evidence suggests that the lungs are the most affected organs by COVID-19. It may also cause corollary and other medical issues. The literature on preceding COVID-19 infections reviews that patients may also experience chronic impairment in breathing characteristics after discharge. The outcome of COVID-19 may remain for weeks to months after the initial recovery. Our goal is to determine the superiority of the restrictive pattern, obstructive pattern, and adjusted diffusion in patients post-COVID-19 contamination and to explain the distinctive opinions of breathing characteristics used with those patients. Therefore, lung function tests were measured post-discharge for three to 12 months. According to estimates, 80% of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-infected patients experienced one or more chronic symptoms. Multidisciplinary teams are required to develop preventive measures, rehabilitation methods, and scientific control plans with a completely patient-centered attitude for long-term COVID-19 care. Clarifying the pathophysiologic mechanisms, creating and testing specific interventions, and treating patients with long-term COVID-19 are urgently needed. The goal of this review is to locate research evaluating COVID-19's long-term effects. A person who has suffered from COVID-19 in the past showed changes in their pulmonary function test. So, we have to notice the changes and recovery from post-COVID-19 effects. COVID-19 survivors were observed in an eventual observational study and continuously examined three, six, and 12 months after having COVID-19 infections. We evaluated the clinical features and concentrations of circulating pulmonary epithelial and endothelial markers in COVID-19 survivors with normal or lower diffusion capacity for carbon monoxide (DLCO) six months after discharge to analyze risk factors and underlying pathophysiology.

"Long Haulers"

Post-COVID conditions continue to afflict patients long after acute severe acute respiratory syndrome-coronavirus-2 (SARS CoV-2) infection. Over 50 symptoms across multiple organ systems have been reported, with pulmonary, cardiovascular, and neuropsychiatric sequelae occurring most frequently. Multiple terms have been used to describe post-COVID conditions including long COVID, long-haul COVID, postacute coronavirus disease 2019 (COVID-19), postacute sequelae of SARS-CoV-2 infection, long-term effects of COVID, and chronic COVID-19; however, standardized assessments and treatment algorithms for patients have generally been lacking. This review discusses the epidemiology and risk factors for post-COVID conditions and provides a general overview of the diagnostic assessment and treatment of specific manifestations. Data derived from the multitude of observational studies and scientific investigations into pathogenesis are providing a clearer understanding of the distinct phenotypes of post-COVID conditions. Insight gained from these studies and ongoing interventional trials continues to lead to the development of clinical protocols directed toward improving COVID-19 survivors' quality of life and preventing or reducing long-term morbidity.

Chronic Pulmonary Manifestations of COVID-19 Infection: Imaging Evaluation

A patient with severe COVID-19 pneumonia requiring ICU admission and prolonged hospital stay is presented. The infection resulted in long term morbidity, functional decline and abnormal chest CT findings. Mechanisms for long term lung injury post COVID-19 infection, imaging appearances and role of imaging in follow-up are discussed.

Pulmonary recovery after COVID-19 - a review

INTRODUCTION

COVID-19 is caused by infection with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). As the respiratory tract is the primary site of infection and host-mediated inflammatory responses, pathologies and dysfunction of the respiratory system characterize the severe disease and are typically associated with the need for oxygen supply or even ventilator support. In survivors of severe COVID-19, computed tomography follow-up frequently reveals structural lung abnormalities, and one-third of individuals who were hospitalized during acute COVID-19 demonstrate persisting lung abnormalities for at least 12 months after disease onset.

AREAS COVERED

This review summarizes current evidence on pulmonary recovery after COVID-19, focusing on adult patients who suffered from COVID-19 pneumonia.

EXPERT OPINION

Severe COVID-19 is associated with a high frequency of persisting lung abnormalities at follow-up. The long-term consequences of these findings remain elusive and urge further evaluation to identify individuals at risk for COVID-19 long-term consequences.

Post-acute COVID-19 symptom risk in hospitalized and non-hospitalized COVID-19 survivors: A systematic review and meta-analysis

Background

Post-acute coronavirus disease 2019 (COVID-19) symptoms occurred in most of the COVID-19 survivors. However, few studies have examined the issue of whether hospitalization results in different post-acute COVID-19 symptom risks. This study aimed to compare potential COVID-19 long-term effects in hospitalized and non-hospitalized COVID-19 survivors.

Methods

This study is designed as a systematic review and meta-analysis of observational studies. A systematic search of six databases was performed for identifying articles published from inception until April 20th, 2022, which compared post-acute COVID-19 symptom risk in hospitalized and non-hospitalized COVID-19 survivors using a predesigned search strategy included terms for SARS-CoV-2 (eg, COVID, coronavirus, and 2019-nCoV), post-acute COVID-19 Syndrome (eg, post-COVID, post COVID conditions, chronic COVID symptom, long COVID, long COVID symptom, long-haul COVID, COVID sequelae, convalescence, and persistent COVID symptom), and hospitalization (hospitalized, in hospital, and home-isolated). The present meta-analysis was conducted according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement using R software 4.1.3 to create forest plots. Q statistics and the I ² index were used to evaluate heterogeneity in this meta-analysis.

Results

Six observational studies conducted in Spain, Austria, Switzerland, Canada, and the USA involving 419 hospitalized and 742 non-hospitalized COVID-19 survivors were included. The number of COVID-19 survivors in included studies ranged from 63 to 431, and follow-up data were collected through visits in four studies and another two used an electronic questionnaire, visit and telephone, respectively. Significant increase in the risks of long dyspnea (OR = 3.18, 95% CI = 1.90-5.32), anxiety (OR = 3.09, 95% CI = 1.47-6.47), myalgia (OR = 2.33, 95% CI = 1.02-5.33), and hair loss (OR = 2.76, 95% CI = 1.07-7.12) risk were found in hospitalized COVID-19 survivors compared with outpatients. Conversely, persisting ageusia risk was significantly reduced in hospitalized COVID-19 survivors than in non-hospitalized patients.

Conclusion

The findings suggested that special attention and patient-centered rehabilitation service based on a needs survey should be provided for hospitalized COVID-19 survivors who experienced high post-acute COVID-19 symptoms risk.

COVID-19 Patients in the COVID-19 Recovery and Engagement (CORE) Clinics in the Bronx

Background: Early in the pandemic, we established COVID-19 Recovery and Engagement (CORE) Clinics in the Bronx and implemented a detailed evaluation protocol to assess physical, emotional, and cognitive function, pulmonary function tests, and imaging for COVID-19 survivors. Here, we report our findings up to five months post-acute COVID-19. Methods: Main outcomes and measures included pulmonary function tests, imaging tests, and a battery of symptom, physical, emotional, and cognitive assessments 5 months post-acute COVID-19. Findings: Dyspnea, fatigue, decreased exercise tolerance, brain fog, and shortness of breath were the most common symptoms but there were generally no significant differences between hospitalized and non-hospitalized cohorts (p > 0.05). Many patients had abnormal physical, emotional, and cognitive scores, but most functioned independently; there were no significant differences between hospitalized and non-hospitalized cohorts (p > 0.05). Six-minute walk tests, lung ultrasound, and diaphragm excursion were abnormal but only in the hospitalized cohort. Pulmonary function tests showed moderately restrictive pulmonary function only in the hospitalized cohort but no obstructive pulmonary function. Newly detected major neurological events, microvascular disease, atrophy, and white-matter changes were rare, but lung opacity and fibrosis-like findings were common after acute COVID-19. Interpretation: Many COVID-19 survivors experienced moderately restrictive pulmonary function, and significant symptoms across the physical, emotional, and cognitive health domains. Newly detected brain imaging abnormalities were rare, but lung imaging abnormalities were common. This study provides insights into post-acute sequelae following SARS-CoV-2 infection in neurological and pulmonary systems which may be used to support at-risk patients and develop effective screening methods and interventions.

Evaluation of Follow-Up CT Scans in Patients with Severe Initial Pulmonary Involvement by COVID-19

Objective

To investigate the predictive factors of residual pulmonary opacity on midterm follow-up CT scans in patients hospitalized with COVID-19 pneumonia.

Materials and Methods

This prospective study was conducted in a tertiary referral university hospital in Iran, from March 2020 to December 2020. Patients hospitalized due to novel coronavirus pneumonia with bilateral pulmonary involvement in the first CT scan were included and underwent an 8-week follow-up CT scan. Pulmonary involvement (PI) severity was assessed using a 25-scale semiquantitative scoring system. Density of opacities was recorded using the Hounsfield unit (HU).

Results

The chest CT scans of 50 participants (mean age = 54.4 ± 14.2 years, 72% male) were reviewed, among whom 8 (16%) had residual findings on follow-up CT scans. The most common residual findings were faint ground-glass opacities (GGOs) (14%); fibrotic-like changes were observed in 2 (4%) patients. Demographic findings, underlying disease, and laboratory findings did not show significant association with remaining pulmonary opacities. The total PI score was significantly higher in participants with remaining parenchymal involvement (14.5 ± 6.5 versus 10.2 ± 3.7; P=0.02). On admission, the HU of patients with remaining opacities was significantly higher (-239.8 ± 107.6 versus -344.0 ± 157.4; P=0.01). Remaining pulmonary findings were more frequently detected in patients who had received antivirals, steroid pulse, or IVIG treatments (P=0.02, 0.02, and 0.001, respectively). Only the PI score remained statistically significant in multivariate logistic regression with 88.1% accuracy (OR = 1.2 [1.01-1.53]; P=0.03).

Conclusion

Pulmonary opacities are more likely to persist in midterm follow-up CT scans in patients with severe initial pulmonary involvement.

Long-Term Effect of COVID-19 on Lung Imaging and Function, Cardiorespiratory Symptoms, Fatigue, Exercise Capacity, and Functional Capacity in Children and Adolescents: A Systematic Review and Meta-Analysis

BACKGROUND

The long-term sequela of COVID-19 on young people is still unknown. This systematic review explored the effect of COVID-19 on lung imaging and function, cardiorespiratory symptoms, fatigue, exercise capacity and functional capacity in children and adolescents ≥ 3 months after infection.

METHODS

A systemic search was completed in the electronic databases of PubMed, Web of Science and Ovid MEDLINE on 27 May 2022. Data on the proportion of participants who had long-term effects were collected, and one-group meta-analysis were used to estimate the pooled prevalence of the outcomes studied.

RESULTS

17 articles met the inclusion criteria, presented data on 124,568 children and adolescents. The pooled prevalence of abnormalities in lung imaging was 10% (95% CI 1-19, I² = 73%), abnormal pulmonary function was 24% (95% CI 4-43, I² = 90%), chest pain/tightness was 6% (95% CI 3-8, I² = 100%), heart rhythm disturbances/palpitations was 6% (95% CI 4-7, I² = 98%), dyspnea/breathing problems was 16% (95% CI 14-19, I² = 99%), and fatigue was 24% (95% CI 20-27, I² = 100%). Decreased exercise capacity and functional limitations were found in 20% (95% CI 4-37, I² = 88%) and 48% (95% CI 25-70, I² = 91%) of the participants studied, respectively.

CONCLUSION

Children and adolescents may have persistent abnormalities in lung imaging and function, cardiorespiratory symptoms, fatigue, and decreased functional capacity between 3 to 12 months after infection. More research is needed to understand the long-term effect of COVID-19 on young people, and to clarify its causes and effective management.