Bilateral Hyperlucent Lungs in an Adult: A Radiologic Approach

Bilateral Hyperlucent Lungs in an Adult: A Radiologic Approach | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Bilateral Hyperlucent Lungs in an Adult: A Radiologic Approach dyutika kantamneni, Mary Salvatore MD This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8127642/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Swyer-James-MacLeod Syndrome (SJMS) is a rare, post-infectious obliterative bronchiolitis, typically presenting as a unilateral hyperlucent lung. Bilateral involvement is rare, with only pediatric cases reported to date. This case highlights an unusual bilateral presentation in an adult, which poses a significant diagnostic challenge. Case presentation: A 30-year-old non-smoking male with a history of recurrent childhood respiratory infections and chronic respiratory symptoms presented with persistent dyspnea. Initial chest radiography was unremarkable, but high-resolution computed tomography (HRCT) revealed bilateral hyperlucent lungs, decreased vascular markings, focal bronchiectasis, and cystic changes. Pulmonary function tests showed an obstructive pattern with a reduced FEV1/FVC ratio (36.79%), increased residual volume (172.6%), and gas trapping. Further workup excluded common differentials like alpha-1-antitrypsin deficiency, cystic fibrosis, and chronic thromboembolic disease. The constellation of findings led to a presumptive diagnosis of bilateral SJMS. Conclusions This case underscores the radiologic approach to bilateral hyperlucent lung in an adult and a presumptive case of SJMS, a finding previously unreported in the literature. It emphasizes the critical role of HRCT in diagnosis. Recognizing this rare presentation is essential to avoid misdiagnosis and guide appropriate conservative management, preventing unnecessary interventions. Pulmonology Laboratory Diagnostics Swyer-James-MacLeod Syndrome Hyperlucent Lung Bronchiolitis Obliterans High-Resolution Computed Tomography Case Report Figures Figure 1 Figure 2 Figure 3 Figure 4 BACKGROUND Bilateral hyperlucent lungs in an adult present a significant diagnostic challenge, requiring a comprehensive approach that integrates clinical history, pulmonary function tests (PFTs), and various imaging modalities such as chest X-rays (CXR) and computed tomography (CT). This case report highlights an atypical presentation in a 30-year-old non-smoking male with a long-standing history of respiratory disease since childhood, including asthma exacerbations and recurrent respiratory infections. Initial CXR findings were normal, but subsequent high-resolution CT (HRCT) revealed bilateral hyperlucent lungs, decreased peripheral vascular markings, focal bronchiectasis, and cystic changes. PFT results indicated an obstructive lung disease pattern with a reduced Forced Expiratory Volume (FEV1) to Forced Volume Capacity (FVC) ratio, increased Total Lung Capacity (TLC), and elevated Residual Volume (RV), indicative of gas trapping. Genetic testing for cystic fibrosis, Quantiferon test for tuberculosis, and Alpha-1-Antitrypsin deficiency test (A1AT) were all negative, ruling out common causes. The clinical and radiographic findings, in conjunction with the exclusion of other differentials like panlobar emphysema, asthma, cystic fibrosis, chronic thromboembolic disease, and pneumothorax, led to a presumed diagnosis of bilateral Swyer-James Macleod syndrome (SJMS). SJMS is a rare, acquired post-infectious pulmonary disorder characterized by hyperlucency of lung parenchyma and reduced vascular markings due to bronchiolitis obliterans (BO), a condition rarely reported bilaterally in adults. This case underscores the limitations of plain radiography and the critical importance of HRCT in diagnosing SJMS, paving the way for accurate diagnosis and effective treatment strategies. Ventilation and perfusion scans (V/Q scans) were not performed in this case, representing a limitation. CASE PRESENTATION A 30-year-old male who is a non-smoker presented to the respiratory clinic with shortness of breath for a routine follow-up of a long-standing respiratory disease since childhood. He reported multiple episodes of shortness of breath of mild to moderate severity over 15 years that were never completely relieved with medications. His past medical history was significant for numerous hospital admissions for asthma exacerbation and recurrent respiratory infections since childhood. Treatment with bronchodilators temporarily reduced his symptoms but not completely. There was no relevant family history of respiratory conditions. His vitals were in the normal range. He was afebrile, and pulse oximetry showed oxygen saturation of 98% on room air. Upon physical examination, there were no concerning findings. Initial PA and lateral chest radiographs were performed. While interpreted as normal initially [ 1 ], subtle findings suggestive of mild hyperinflation were present, including visualization of more than six anterior ribs and flattening of the diaphragm, best appreciated on the lateral view. Further computed tomography (CT) was performed. Previous CT scans performed over the past 10 years had similar findings and have been stable. Pulmonary function test (PFT) were performed to assess to look for evidence of respiratory disease which displayed the following results: Pulmonary function test Value (%) Forced expiratory volume (FEV1) 1.65 L (43.7%) Forced volume capacity (FVC) 4.47 L (99.6%) Ratio FEV1/FVC 36.79% Residual volume (RV) 2.86L (172.6%) Total lung capacity (TLC) 7.3 L (112.3%) Diffusion capacity of lung for carbon monoxide (DLCO) 26.12 ml/(min*mmHg) (88.3%) PFT suggests obstructive lung disease based on the FEV1/FVC ratio (< 70% is considered obstructive), further a decrease in FEV1, increased TLC, and residual lung volume indicative of gas trapping, further supporting the diagnosis [ 9 ]. Radiologic manifestations on HRCT of the patient include: ● Hyperlucency of bilateral lung fields ● Decreased pulmonary vascular markings in the affected regions with a mild decrease in the main pulmonary artery diameter [main PA- 2.27cm, right PA 1.69cm, left PA − 1.7cm ]. ● Unilateral small thin-walled Cysts ● Bronchiectasis in the right lower lobe with chronic mucoid impaction Additional tests were done to rule out other potential causes. Genetic testing and the sweat chloride test were negative, ruling out cystic fibrosis; the Quantiferon test was negative, ruling out tuberculosis, and the alpha-1-antitrypsin deficiency test (A1AT) was negative as well [ 3 , 8 ]. Advanced functional imaging (V/Q scan) and bronchoscopy with bronchoalveolar lavage were not performed during this evaluation. Radiographic differentials of hyperlucent lung: The differential diagnosis considered on basis of radiographic and clinical findings includes: Panlobar Emphysema -the most common congenital cause being alpha-1-antitrypsin (A1AT) deficiency, which was ruled out on the basis of normal serum levels of A1AT levels[2,8]. Asthma would have a more severe clinical presentation and clinical history mentioned that the symptoms were not reversible with treatment. The vascular markings are normal and are attenuated only when associated with bronchiectasis [2,27]. Swyer-James Syndrome is characterised by hyperlucent lung secondary to infectious bronchiolitis with decreased vasculature and pulmonary artery hypoplasia [2] Cystic fibrosis or Primary ciliary dyskinesia – Both are characterized by cystic bronchiectasis, which is absent here and typically manifests early in life [28]. Chronic thromboembolic disease - would typically lead to Right heart strain and right heart border displacement, which isn’t seen on CXR. Additionally, CT did not demonstrate interventricular septal deviation [2]. Hypoplasia of a pulmonary artery is not associated with air trapping or bronchiectasis [2]. Congenital lobar emphysema in adults has very similar radiographic findings, but the presence of multiple childhood infections makes the association less likely; furthermore, reported cases only mention the involvement of some lobes and are not bilateral [29]. Pneumothorax - pleural edge would be seen separately with no peripheral lung markings and, if bilateral, would cause severe respiratory distress [2]. Pneumatocele would appear as a thin-walled gas-containing cystic space within normal lung parenchyma, which is not seen here [2]. The differential diagnosis considered on the basis of radiographic and clinical findings included those mentioned in Fig. 4 . These were systematically ruled out based on the patient's history, imaging characteristics, and laboratory results, as previously detailed. Follow-up and Outcome The patient has been maintained on a conservative regimen of bronchodilators and corticosteroids and has remained under active clinical surveillance. Over several years of follow-up, he has reported stable symptoms with no clinical progression. Repeat imaging has confirmed that the characteristic HRCT findings have remained unchanged, supporting the indolent nature of his condition. This is a case of bilateral hyperlucent lung in an adult case, presumed to be Swyer-James Macleod syndrome (SJMS). There have been five recorded cases of bilateral SJMS in children to date [ 11 ]. SJMS is a rare condition of the lung characterized by hyperlucency of the lung and decreased pulmonary vascular markings on the affected side on radiographic examination. This syndrome was first described in 1953 in a six-year-old boy from the UK by Paul Robert Swyer and George C.W. James. The following year, Macleod reported 9 cases of SJMS in adults [ 4 , 10 ]. It is proposed to be an acquired disease secondary to childhood respiratory infections caused by viruses (Paramyxovirus morbillivirus, influenza A, adenovirus) or bacteria (Bordetella pertussis, Mycobacterium tuberculosis, Mycoplasma pneumoniae) [ 7 ]. Infections of the lungs due to these causative organisms in childhood lead to Constrictive Bronchiolitis obliterans (BO), which can damage the terminal and respiratory bronchioles before complete development and maturation of the lung, causing improper growth of the alveolar sacs and lung tissue [ 4 , 7 , 11 , 12 ]. These pathogens cause inflammation and fibrosis of the walls and tissue of the respiratory bronchiole, which leads to obliteration of the lumen, thereby causing air trapping and a hyperlucent appearance of the lung on CT [ 13 ]. The distribution is typically lobar, segmental, or involves the entire lung [ 12 , 14 ]. In 2 studies, approximately 4% of those with Bronchiolitis obliterans had this syndrome [ 16 , 30 ]. Further, the prevalence of SJMS was only 0.01% per 17,450 chest radiographs, making it hard to diagnose with chest radiographs alone [ 7 , 15 , 17 ]. On PFT, SJMS is reported to most commonly have an obstructive pattern secondary to a bronchial narrowing, which was observed in our cases as well [ 7 , 18 , 19 ]. Typical Radiographic findings in Swyer-James syndrome Radiographic diagnostic criteria for Swyer-James syndrome include [ 4 ]: a) unilateral loss of lung volume with hyperlucency on chest x-ray b) unilateral reduction in vascularity on CT scan of the chest c) unilateral loss of perfusion on technetium 99 c lung scan. Chest X-ray On chest x-ray, there may be hyperlucency of the lung, hyperinflation of the affected lung, decreased bronchovascular markings, and a shift of the mediastinum to the hypoplastic side of the lung during inspiration [ 5 , 11 , 20 ]. CT scans are more sensitive than radiographs to detect this condition [ 5 , 7 ]. CT CT scans demonstrate hyper lucency involving unilateral or bilateral lungs and a decrease in pulmonary vascular markings, with or without additional bronchiectasis and cystic changes [ 5 ]. Air trapping results from obstruction of the small air spaces [ 13 ]. The decrease in pulmonary vascular markings is attributed to fibrosis of the interalveolar septae, which house the capillaries, and secondarily decreases the blood flow to the secondary pulmonary lobules [ 20 ]. Hypoxic vasoconstriction leads to hypoperfusion of the affected areas and decreased bronchovascular markings [ 21 ]. Hyperexpansion of the alveoli further causes mechanical pressure on the flow of the alveolar capillaries and further contributes to vessel atrophy [ 20 ]. The mean lung attenuation of -950 Hounsfield Units (HU) seen in our case is profoundly abnormal, quantitatively confirming severe air trapping. This value is a recognized threshold for parenchymal destruction in obstructive lung diseases like emphysema and, in this context, objectively confirms the visually apparent hyperlucency caused by bronchiolitis obliterans [ 31 ]. the Framingham Heart Study states that the pulmonary artery diameter ranges from 25.1 ± 2.8 mm on non-contrast CT [ 19 ]. The main pulmonary artery diameter in our study measured 22.7 mm. When compared to established reference values [ 6 ], our case shows a value that falls more than one standard deviation below the mean, indicating true pulmonary artery hypoplasia consistent with the chronic reduced blood flow in SJMS. Deviation from these values may indicate a pathology, including pulmonary artery hypertension or hypoplasia. In SJMS, pulmonary artery hypoplasia can be observed in a number of cases, thus making the measurement of the pulmonary artery diameter important. V/Q scans Ventilation and perfusion scans are used for diagnostic purposes to differentiate between a vascular cause and a ventilatory cause of hyperlucency. In patients with SJMS, a decrease in both ventilation and perfusion secondary to increased filling of intrapulmonary branches is observed [ 11 ]. Macroscopically, there are emphysematous changes, cysts, and pulmonary hypoplasia in some cases, where the dilated cysts may represent dilated bronchioles [ 10 ]. Microscopically, there are emphysematous changes in the alveoli with thin walls and dilated bronchioles, and the most striking feature is the widespread obliteration of the lung capillaries in the walls of the emphysematous alveoli [ 10 , 25 ]. CONCLUSION SJMS is a rare, post-infectious pulmonary disorder characterized by hyperlucency of lung parenchyma and reduced vascular markings due to bronchiolitis obliterans. This case describes a 30-year-old male with a history of recurrent childhood respiratory infections and chronic respiratory symptoms, ultimately presumed to have bilateral SJMS, an infrequent presentation in adults. Though the initial CXR appeared normal, HRCT revealed bilateral hyperlucent lungs, decreased peripheral vascular markings, focal bronchiectasis, and cystic changes. These findings highlight the limitations of plain radiography and underscore the importance of HRCT in diagnosing SJMS PFT demonstrated an obstructive finding. Asthma was considered but discounted due to the absence of generalized airway involvement, attenuation of vascular markings, and a suboptimal response to bronchodilator therapy in clinical history. Similarly, emphysema was ruled out based on the patient's young age, non-smoking status, lack of diffuse alveolar destruction, and a negative alpha-1-antitrypsin assay. Patients can be both asymptomatic or symptomatic, with symptoms ranging from chronic productive cough, exertional dyspnoea, chest pain, hemoptysis, increased recurrent infections, and decreased exercise tolerance [ 20 , 22 ]. A number of patients are asymptomatic and are often diagnosed incidentally during imaging for other reasons [ 23 , 24 ]. Complications include recurrent pneumonia, bullae, cysts, lung abscesses, and spontaneous pneumothorax [ 7 ]. As shown in Table 1 , our case shares the hallmark features of SJMS seen in unilateral adult cases, including a history of childhood infection, obstructive physiology on PFTs, and the classic HRCT findings of hyperlucency and vascular pruning [ 7 , 14 , 23 , 24 ]. The critical differentiating factor is the symmetrical bilateral involvement in our patient, which, to our knowledge, has not been previously reported in an adult. In summary, we present an atypical case of bilateral hyperlucent lung in an adult presumed to be SJMS, a radiographic diagnosis that has only been recorded in children [ 11 ]. Recognizing this allows for a careful evaluation of both clinical and radiographic evidence, paving the way for an accurate diagnosis and effective treatment strategy. Table 1 Comparative Features of Reported Unilateral Adult SJMS Cases and the Present Bilateral Case. Study Sen et al.2014 [ 7 ] Abba & Al- Mobeireek (2003) [ 14 ] Conti L et al. 2021 [ 23 ] Capela C et al.2011 [ 24 ] Current study Age 30–50’s 30–40’s 42 53 30 History of childhood infections Mixed – some had and some didn’t childhood No history reccurent pulmonary infections in childhood reccurent infections in childhood Key Symptoms dyspnea, cough, hemoptysis, chest pain, sputum cough, SOB, hemoptysis, dyspnea, pleuritic chest pain chronic productive cough, dyspnea on exertion, PND, edema and central cyanosis persistent dsypnea Imaging features unilateral hyperlucency, bronchiectasis, unilateral pulmonary artery hypoplasia Unilateral hyperlucency, bronchiectasis Unilateral hyperlucency, cystic bronchiectasis unilateral hyperlucency and diminished vascularity bilateral hyperlucency with reduced vascular markings, mild cystic bronchiectasis PFT Obstructive Obstructive no abnormalities obstructive - restrictive pattern Obstructive V/Q NA some had a matched reduced V/Q No V/Q mismatch NA NA Management bronchodilators, corticosteroid, antibiotics Conservative pneumectomy and lobectomy for pneumothorax bronchodilator bronchodilators Combining characteristic imaging features, an obstructive PFT pattern, and excluding other differentials supported a presumptive diagnosis of bilateral SJMS. It is important to note that this diagnosis remains presumptive, as histology and V/Q scintigraphy were not performed[ 4 , 7 , 13 ], which would have provided functional characterization of the matched ventilation-perfusion defects for this syndrome. Nevertheless, his sustained stability matches the often-indolent course described in unilateral cases and supports the role of conservative management as a mainstay of treatment. Despite these limitations, the constellation of a compelling clinical history, classic imaging findings on HRCT, and the exclusion of major alternative diagnoses provides a strong basis for this diagnosis. This case underscores that SJMS can present bilaterally in adults and highlights the critical role of HRCT in identifying this underrecognized condition. Treatment for SJMS ranges from conservative to surgical management and appropriate immunization; conservative symptomatic management with inhaled bronchodilators and low-dose inhaled corticosteroids is the mainstay of treatment [ 7 , 10 , 12 , 13 ]. In the case of severe bronchiectasis leading to recurrent infections, pneumonectomy was shown to improve quality of life through improving PFTs, and surgical interventions like lung resections have also been used for recalcitrant disease or patients with complications [ 25 , 26 ]. Abbreviations A1AT Alpha-1-Antitrypsin BO Bronchiolitis Obliterans CXR Chest X-ray CT Computed Tomography FEV1 Forced Expiratory Volume in 1 second FVC Forced Vital Capacity HRCT High-Resolution Computed Tomography PA Pulmonary Artery PFTs Pulmonary Function Tests RV Residual Volume SJMS Swyer-James-MacLeod Syndrome TLC Total Lung Capacity V/Q Scan Ventilation/Perfusion Scan Declarations Ethics approval and consent to participate Not applicable Consent for publication Written informed consent to publish was taken from the person. Availability of data and materials All relevant data supporting this case report are included within the manuscript. Competing interests The authors declare that they have no competing interests Funding This case report did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. 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Am J Respir Crit Care Med 182(5):614–626. 10.1164/rccm.201001-0092OC Sadaqat M, Malik JA, Karim R (2011) Congenital lobar emphysema in an adult. Lung India 28(1):67–69. 10.4103/0970-2113.76307 Gold R, Wilt JC, Adhikari PK, Macpherson RI (1969) Adenoviral pneumonia and its complications in infancy and childhood. J Can Assoc Radiol 20(4):218–224 Fernandes L, Fernandes Y, Mesquita AM (2016 Nov-Dec) Quantitative computed tomography imaging in chronic obstructive pulmonary disease. Lung India 33(6):646–652. 10.4103/0970-2113.192880 PMID: 27890994; PMCID: PMC5112822 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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07:31:13","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":161871,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/30d37dcac1356e4c7090a5e4.png"},{"id":96251197,"identity":"c771d53e-2734-4e97-9395-a4f774bc77bf","added_by":"auto","created_at":"2025-11-19 07:39:29","extension":"xml","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":79420,"visible":true,"origin":"","legend":"","description":"","filename":"rs81276420structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/9a125dcf6b8cd8ef8b6b3a81.xml"},{"id":96162329,"identity":"6bf825b6-cda3-4831-a13b-685b68fe37d3","added_by":"auto","created_at":"2025-11-18 08:58:45","extension":"html","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":90375,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/dcd2034eb18f1015fcd36a73.html"},{"id":96162315,"identity":"754965f2-7125-4ea5-847c-616b8e604084","added_by":"auto","created_at":"2025-11-18 08:58:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":382820,"visible":true,"origin":"","legend":"\u003cp\u003e(a)\u003cstrong\u003e \u003c/strong\u003ePosteroanterior and (b) lateral chest radiograph showing flattening of the diaphragm and visualization of more than 6 anterior ribs.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/efecc7f4cbc5497a61ca5a2f.png"},{"id":96251306,"identity":"bf746efa-6023-4c1c-b6a9-65aaf3562511","added_by":"auto","created_at":"2025-11-19 07:39:37","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":490025,"visible":true,"origin":"","legend":"\u003cp\u003eHigh-resolution CT (HRCT) showing an axial lung window view (mediastinal) demonstrates:\u003c/p\u003e\n\u003cp\u003eA] Bilateral hyperlucent lungs and decreased peripheral vascular markings with decreased attenuation measuring -950 Hu with areas of bronchial wall thickening (white arrow) [2]\u003c/p\u003e\n\u003cp\u003eB] Cyst with regular walls in the right middle lobe (white arrow) [4]\u003c/p\u003e\n\u003cp\u003eC] Bronchiectasis in the right lower lobe with chronic mucoid impaction also present in past CT scans [5]\u003c/p\u003e\n\u003cp\u003eD] Decreased pulmonary artery (PA) size discernible only by measurement (arrowhead) [main PA- 2.27cm, right PA 1.69cm, left PA - 1.7cm [6].\u003c/p\u003e\n\u003cp\u003eE] Bronchial wall thickening (arrow) [4,7]\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/59462025dd5cf5a2dff2d936.png"},{"id":96162321,"identity":"b9e07366-a710-4da1-be76-b940c16e7d95","added_by":"auto","created_at":"2025-11-18 08:58:45","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":54905,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe flowchart illustrates the division of hyperlucent lungs based on congenital and acquired factors.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/2af0690c4a5c47182bcbc62a.png"},{"id":96162319,"identity":"7e8299f9-2d0e-4d42-8c02-4de2c79ef3ee","added_by":"auto","created_at":"2025-11-18 08:58:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":91942,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe flowchart illustrates the division of hyperlucent lungs based on airway and vascular etiology\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/e90350fe480c6d201ea6d9dc.png"},{"id":96256947,"identity":"a71d996f-a675-492d-9206-4273eeef4a52","added_by":"auto","created_at":"2025-11-19 07:51:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1835882,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8127642/v1/ab031bdf-9685-4762-a362-69eafab2c7af.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eBilateral Hyperlucent Lungs in an Adult: A Radiologic Approach\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eBilateral hyperlucent lungs in an adult present a significant diagnostic challenge, requiring a comprehensive approach that integrates clinical history, pulmonary function tests (PFTs), and various imaging modalities such as chest X-rays (CXR) and computed tomography (CT). This case report highlights an atypical presentation in a 30-year-old non-smoking male with a long-standing history of respiratory disease since childhood, including asthma exacerbations and recurrent respiratory infections. Initial CXR findings were normal, but subsequent high-resolution CT (HRCT) revealed bilateral hyperlucent lungs, decreased peripheral vascular markings, focal bronchiectasis, and cystic changes. PFT results indicated an obstructive lung disease pattern with a reduced Forced Expiratory Volume (FEV1) to Forced Volume Capacity (FVC) ratio, increased Total Lung Capacity (TLC), and elevated Residual Volume (RV), indicative of gas trapping. Genetic testing for cystic fibrosis, Quantiferon test for tuberculosis, and Alpha-1-Antitrypsin deficiency test (A1AT) were all negative, ruling out common causes. The clinical and radiographic findings, in conjunction with the exclusion of other differentials like panlobar emphysema, asthma, cystic fibrosis, chronic thromboembolic disease, and pneumothorax, led to a presumed diagnosis of bilateral Swyer-James Macleod syndrome (SJMS). SJMS is a rare, acquired post-infectious pulmonary disorder characterized by hyperlucency of lung parenchyma and reduced vascular markings due to bronchiolitis obliterans (BO), a condition rarely reported bilaterally in adults. This case underscores the limitations of plain radiography and the critical importance of HRCT in diagnosing SJMS, paving the way for accurate diagnosis and effective treatment strategies. Ventilation and perfusion scans (V/Q scans) were not performed in this case, representing a limitation.\u003c/p\u003e"},{"header":"CASE PRESENTATION","content":"\u003cp\u003eA 30-year-old male who is a non-smoker presented to the respiratory clinic with shortness of breath for a routine follow-up of a long-standing respiratory disease since childhood. He reported multiple episodes of shortness of breath of mild to moderate severity over 15 years that were never completely relieved with medications. His past medical history was significant for numerous hospital admissions for asthma exacerbation and recurrent respiratory infections since childhood. Treatment with bronchodilators temporarily reduced his symptoms but not completely. There was no relevant family history of respiratory conditions. His vitals were in the normal range. He was afebrile, and pulse oximetry showed oxygen saturation of 98% on room air. Upon physical examination, there were no concerning findings.\u003c/p\u003e\n\u003cp\u003eInitial PA and lateral chest radiographs were performed. While interpreted as normal initially [\u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e], subtle findings suggestive of mild hyperinflation were present, including visualization of more than six anterior ribs and flattening of the diaphragm, best appreciated on the lateral view. Further computed tomography (CT) was performed. Previous CT scans performed over the past 10 years had similar findings and have been stable.\u003c/p\u003e\n\u003cp\u003ePulmonary function test (PFT) were performed to assess to look for evidence of respiratory disease which displayed the following results:\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\n \u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePulmonary function test\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eValue (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eForced expiratory volume (FEV1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.65 L (43.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eForced volume capacity (FVC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.47 L (99.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRatio FEV1/FVC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.79%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResidual volume (RV)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.86L (172.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTotal lung capacity (TLC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.3 L (112.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiffusion capacity of lung for carbon monoxide (DLCO)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.12 ml/(min*mmHg) (88.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003ePFT suggests obstructive lung disease based on the FEV1/FVC ratio (\u0026lt;\u0026thinsp;70% is considered obstructive), further a decrease in FEV1, increased TLC, and residual lung volume indicative of gas trapping, further supporting the diagnosis [\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eRadiologic manifestations on HRCT of the patient include:\u003c/h2\u003e\n \u003cp\u003e● Hyperlucency of bilateral lung fields\u003c/p\u003e\n \u003cp\u003e● Decreased pulmonary vascular markings in the affected regions with a mild decrease in the main pulmonary artery diameter [main PA- 2.27cm, right PA 1.69cm, left PA \u0026minus;\u0026thinsp;1.7cm ].\u003c/p\u003e\n \u003cp\u003e● Unilateral small thin-walled Cysts\u003c/p\u003e\n \u003cp\u003e● Bronchiectasis in the right lower lobe with chronic mucoid impaction\u003c/p\u003e\n \u003cp\u003eAdditional tests were done to rule out other potential causes. Genetic testing and the sweat chloride test were negative, ruling out cystic fibrosis; the Quantiferon test was negative, ruling out tuberculosis, and the alpha-1-antitrypsin deficiency test (A1AT) was negative as well [\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e]. Advanced functional imaging (V/Q scan) and bronchoscopy with bronchoalveolar lavage were not performed during this evaluation.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eRadiographic differentials of hyperlucent lung:\u003c/h3\u003e\n\u003cp\u003eThe differential diagnosis considered on basis of radiographic and clinical findings includes:\u003c/p\u003e\n\u003col start=\"1\" type=\"a\"\u003e\n \u003cli\u003ePanlobar Emphysema -the most common congenital cause being alpha-1-antitrypsin\u0026nbsp;(A1AT) deficiency, which was ruled out on the basis of normal serum levels of A1AT levels[2,8].\u003c/li\u003e\n \u003cli\u003eAsthma would have a more severe clinical presentation and clinical history mentioned that the symptoms were not reversible with treatment. The vascular markings are normal and are attenuated only when associated with bronchiectasis [2,27].\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSwyer-James Syndrome is characterised by hyperlucent lung secondary to infectious bronchiolitis with decreased vasculature and pulmonary artery hypoplasia [2]\u003c/li\u003e\n \u003cli\u003eCystic fibrosis or Primary ciliary dyskinesia \u0026ndash; Both are characterized by cystic bronchiectasis, which is absent here and typically manifests early in life [28].\u003c/li\u003e\n \u003cli\u003eChronic thromboembolic disease - would\u0026nbsp;typically\u0026nbsp;lead to Right heart strain and right heart border displacement, which isn\u0026rsquo;t seen on CXR. Additionally, CT did not demonstrate interventricular septal deviation [2].\u003c/li\u003e\n \u003cli\u003eHypoplasia of a pulmonary artery is not associated with air trapping or bronchiectasis [2].\u003c/li\u003e\n \u003cli\u003eCongenital lobar emphysema in adults has very similar radiographic findings, but the presence of multiple childhood infections makes the association less likely; furthermore, reported cases only mention the involvement of some lobes and are not bilateral [29].\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePneumothorax - pleural edge would be seen separately with no peripheral lung markings and, if bilateral, would cause severe respiratory distress [2].\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePneumatocele would appear as a thin-walled gas-containing cystic space within normal lung parenchyma, which is not seen here [2].\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003eThe differential diagnosis considered on the basis of radiographic and clinical findings included those mentioned in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. These were systematically ruled out based on the patient\u0026apos;s history, imaging characteristics, and laboratory results, as previously detailed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFollow-up and Outcome\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe patient has been maintained on a conservative regimen of bronchodilators and corticosteroids and has remained under active clinical surveillance. Over several years of follow-up, he has reported stable symptoms with no clinical progression. Repeat imaging has confirmed that the characteristic HRCT findings have remained unchanged, supporting the indolent nature of his condition.\u003c/p\u003e\n\u003cp\u003eThis is a case of bilateral hyperlucent lung in an adult case, presumed to be Swyer-James Macleod syndrome (SJMS). There have been five recorded cases of bilateral SJMS in children to date [\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eSJMS is a rare condition of the lung characterized by hyperlucency of the lung and decreased pulmonary vascular markings on the affected side on radiographic examination. This syndrome was first described in 1953 in a six-year-old boy from the UK by Paul Robert Swyer and George C.W. James. The following year, Macleod reported 9 cases of SJMS in adults [\u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e]. It is proposed to be an acquired disease secondary to childhood respiratory infections caused by viruses (Paramyxovirus morbillivirus, influenza A, adenovirus) or bacteria (Bordetella pertussis, Mycobacterium tuberculosis, Mycoplasma pneumoniae) [\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]. Infections of the lungs due to these causative organisms in childhood lead to Constrictive Bronchiolitis obliterans (BO), which can damage the terminal and respiratory bronchioles before complete development and maturation of the lung, causing improper growth of the alveolar sacs and lung tissue [\u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e]. These pathogens cause inflammation and fibrosis of the walls and tissue of the respiratory bronchiole, which leads to obliteration of the lumen, thereby causing air trapping and a hyperlucent appearance of the lung on CT [\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]. The distribution is typically lobar, segmental, or involves the entire lung [\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]. In 2 studies, approximately 4% of those with Bronchiolitis obliterans had this syndrome [\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e]. Further, the prevalence of SJMS was only 0.01% per 17,450 chest radiographs, making it hard to diagnose with chest radiographs alone [\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. On PFT, SJMS is reported to most commonly have an obstructive pattern secondary to a bronchial narrowing, which was observed in our cases as well [\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eTypical Radiographic findings in Swyer-James syndrome\u003c/h3\u003e\n\u003cp\u003eRadiographic diagnostic criteria for Swyer-James syndrome include [\u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e]:\u003c/p\u003e\n\u003cp\u003ea) unilateral loss of lung volume with hyperlucency on chest x-ray\u003c/p\u003e\n\u003cp\u003eb) unilateral reduction in vascularity on CT scan of the chest\u003c/p\u003e\n\u003cp\u003ec) unilateral loss of perfusion on technetium 99 c lung scan.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eChest X-ray\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOn chest x-ray, there may be hyperlucency of the lung, hyperinflation of the affected lung, decreased bronchovascular markings, and a shift of the mediastinum to the hypoplastic side of the lung during inspiration [\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e]. CT scans are more sensitive than radiographs to detect this condition [\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCT scans demonstrate hyper lucency involving unilateral or bilateral lungs and a decrease in pulmonary vascular markings, with or without additional bronchiectasis and cystic changes [\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e]. Air trapping results from obstruction of the small air spaces [\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]. The decrease in pulmonary vascular markings is attributed to fibrosis of the interalveolar septae, which house the capillaries, and secondarily decreases the blood flow to the secondary pulmonary lobules [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e]. Hypoxic vasoconstriction leads to hypoperfusion of the affected areas and decreased bronchovascular markings [\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e]. Hyperexpansion of the alveoli further causes mechanical pressure on the flow of the alveolar capillaries and further contributes to vessel atrophy [\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e]. The mean lung attenuation of -950 Hounsfield Units (HU) seen in our case is profoundly abnormal, quantitatively confirming severe air trapping. This value is a recognized threshold for parenchymal destruction in obstructive lung diseases like emphysema and, in this context, objectively confirms the visually apparent hyperlucency caused by bronchiolitis obliterans [\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003ethe Framingham Heart Study states that the pulmonary artery diameter ranges from 25.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8 mm on non-contrast CT [\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e]. The main pulmonary artery diameter in our study measured 22.7 mm. When compared to established reference values [\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e], our case shows a value that falls more than one standard deviation below the mean, indicating true pulmonary artery hypoplasia consistent with the chronic reduced blood flow in SJMS. Deviation from these values may indicate a pathology, including pulmonary artery hypertension or hypoplasia. In SJMS, pulmonary artery hypoplasia can be observed in a number of cases, thus making the measurement of the pulmonary artery diameter important.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eV/Q scans\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eVentilation and perfusion scans are used for diagnostic purposes to differentiate between a vascular cause and a ventilatory cause of hyperlucency. In patients with SJMS, a decrease in both ventilation and perfusion secondary to increased filling of intrapulmonary branches is observed [\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eMacroscopically, there are emphysematous changes, cysts, and pulmonary hypoplasia in some cases, where the dilated cysts may represent dilated bronchioles [\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e]. Microscopically, there are emphysematous changes in the alveoli with thin walls and dilated bronchioles, and the most striking feature is the widespread obliteration of the lung capillaries in the walls of the emphysematous alveoli [\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eSJMS is a rare, post-infectious pulmonary disorder characterized by hyperlucency of lung parenchyma and reduced vascular markings due to bronchiolitis obliterans. This case describes a 30-year-old male with a history of recurrent childhood respiratory infections and chronic respiratory symptoms, ultimately presumed to have bilateral SJMS, an infrequent presentation in adults. Though the initial CXR appeared normal, HRCT revealed bilateral hyperlucent lungs, decreased peripheral vascular markings, focal bronchiectasis, and cystic changes. These findings highlight the limitations of plain radiography and underscore the importance of HRCT in diagnosing SJMS\u003c/p\u003e\u003cp\u003ePFT demonstrated an obstructive finding. Asthma was considered but discounted due to the absence of generalized airway involvement, attenuation of vascular markings, and a suboptimal response to bronchodilator therapy in clinical history. Similarly, emphysema was ruled out based on the patient's young age, non-smoking status, lack of diffuse alveolar destruction, and a negative alpha-1-antitrypsin assay. Patients can be both asymptomatic or symptomatic, with symptoms ranging from chronic productive cough, exertional dyspnoea, chest pain, hemoptysis, increased recurrent infections, and decreased exercise tolerance [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. A number of patients are asymptomatic and are often diagnosed incidentally during imaging for other reasons [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Complications include recurrent pneumonia, bullae, cysts, lung abscesses, and spontaneous pneumothorax [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, our case shares the hallmark features of SJMS seen in unilateral adult cases, including a history of childhood infection, obstructive physiology on PFTs, and the classic HRCT findings of hyperlucency and vascular pruning [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The critical differentiating factor is the symmetrical bilateral involvement in our patient, which, to our knowledge, has not been previously reported in an adult.\u003c/p\u003e\u003cp\u003eIn summary, we present an atypical case of bilateral hyperlucent lung in an adult presumed to be SJMS, a radiographic diagnosis that has only been recorded in children [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Recognizing this allows for a careful evaluation of both clinical and radiographic evidence, paving the way for an accurate diagnosis and effective treatment strategy.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparative Features of Reported Unilateral Adult SJMS Cases and the Present Bilateral Case.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStudy\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSen et al.2014 [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAbba \u0026amp; Al-\u003c/p\u003e\u003cp\u003eMobeireek\u003c/p\u003e\u003cp\u003e(2003) [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eConti L et al.\u003c/p\u003e\u003cp\u003e2021 [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCapela C et al.2011\u003c/p\u003e\u003cp\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCurrent study\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u0026ndash;50\u0026rsquo;s\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30\u0026ndash;40\u0026rsquo;s\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eHistory of\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003echildhood\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003einfections\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMixed \u0026ndash; some had\u003c/p\u003e\u003cp\u003eand some didn\u0026rsquo;t\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003echildhood\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo history\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ereccurent pulmonary\u003c/p\u003e\u003cp\u003einfections in\u003c/p\u003e\u003cp\u003echildhood\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ereccurent infections in\u003c/p\u003e\u003cp\u003echildhood\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eKey Symptoms\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003edyspnea, cough,\u003c/p\u003e\u003cp\u003ehemoptysis,\u003c/p\u003e\u003cp\u003echest pain,\u003c/p\u003e\u003cp\u003esputum\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ecough, SOB,\u003c/p\u003e\u003cp\u003ehemoptysis,\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003edyspnea,\u003c/p\u003e\u003cp\u003epleuritic\u003c/p\u003e\u003cp\u003echest pain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003echronic productive\u003c/p\u003e\u003cp\u003ecough, dyspnea on\u003c/p\u003e\u003cp\u003eexertion, PND, edema\u003c/p\u003e\u003cp\u003eand central cyanosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003epersistent dsypnea\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eImaging features\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eunilateral\u003c/p\u003e\u003cp\u003ehyperlucency,\u003c/p\u003e\u003cp\u003ebronchiectasis,\u003c/p\u003e\u003cp\u003eunilateral pulmonary\u003c/p\u003e\u003cp\u003eartery\u003c/p\u003e\u003cp\u003ehypoplasia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eUnilateral\u003c/p\u003e\u003cp\u003ehyperlucency,\u003c/p\u003e\u003cp\u003ebronchiectasis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eUnilateral\u003c/p\u003e\u003cp\u003ehyperlucency,\u003c/p\u003e\u003cp\u003ecystic\u003c/p\u003e\u003cp\u003ebronchiectasis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eunilateral\u003c/p\u003e\u003cp\u003ehyperlucency and\u003c/p\u003e\u003cp\u003ediminished\u003c/p\u003e\u003cp\u003evascularity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ebilateral hyperlucency\u003c/p\u003e\u003cp\u003ewith reduced vascular\u003c/p\u003e\u003cp\u003emarkings, mild cystic bronchiectasis\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePFT\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eObstructive\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eObstructive\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eno abnormalities\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eobstructive -\u003c/p\u003e\u003cp\u003erestrictive pattern\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eObstructive\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eV/Q\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003esome had a\u003c/p\u003e\u003cp\u003ematched reduced\u003c/p\u003e\u003cp\u003eV/Q\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNo V/Q\u003c/p\u003e\u003cp\u003emismatch\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eManagement\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ebronchodilators,\u003c/p\u003e\u003cp\u003ecorticosteroid,\u003c/p\u003e\u003cp\u003eantibiotics\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eConservative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003epneumectomy\u003c/p\u003e\u003cp\u003eand lobectomy\u003c/p\u003e\u003cp\u003efor pneumothorax\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ebronchodilator\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ebronchodilators\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eCombining characteristic imaging features, an obstructive PFT pattern, and excluding other differentials supported a presumptive diagnosis of bilateral SJMS. It is important to note that this diagnosis remains presumptive, as histology and V/Q scintigraphy were not performed[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], which would have provided functional characterization of the matched ventilation-perfusion defects for this syndrome. Nevertheless, his sustained stability matches the often-indolent course described in unilateral cases and supports the role of conservative management as a mainstay of treatment. Despite these limitations, the constellation of a compelling clinical history, classic imaging findings on HRCT, and the exclusion of major alternative diagnoses provides a strong basis for this diagnosis. This case underscores that SJMS can present bilaterally in adults and highlights the critical role of HRCT in identifying this underrecognized condition. Treatment for SJMS ranges from conservative to surgical management and appropriate immunization; conservative symptomatic management with inhaled bronchodilators and low-dose inhaled corticosteroids is the mainstay of treatment [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In the case of severe bronchiectasis leading to recurrent infections, pneumonectomy was shown to improve quality of life through improving PFTs, and surgical interventions like lung resections have also been used for recalcitrant disease or patients with complications [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eA1AT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eAlpha-1-Antitrypsin\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eBO\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBronchiolitis Obliterans\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCXR\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eChest X-ray\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eCT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eComputed Tomography\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFEV1\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eForced Expiratory Volume in 1 second\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eFVC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eForced Vital Capacity\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eHRCT\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eHigh-Resolution Computed Tomography\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePA\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePulmonary Artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePFTs\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePulmonary Function Tests\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eRV\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eResidual Volume\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eSJMS\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eSwyer-James-MacLeod Syndrome\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eTLC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eTotal Lung Capacity\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eV/Q Scan\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eVentilation/Perfusion Scan\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent to publish was taken from the person.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll relevant data supporting this case report are included within the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis case report did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDK did a literature review and helped in writing the manuscript\u003c/p\u003e\n\u003cp\u003eMS helped in writing the script, acquiring images, and reviewing the case report.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll authors reviewed and approved the final manuscript before submission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWestra D, Sperber M (2001) Conventional Chest Radiography. \u003cem\u003eRadiologic Diagnosis of Chest Disease\u003c/em\u003e. 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Lung India 28(1):67\u0026ndash;69. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.4103/0970-2113.76307\u003c/span\u003e\u003cspan address=\"10.4103/0970-2113.76307\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGold R, Wilt JC, Adhikari PK, Macpherson RI (1969) Adenoviral pneumonia and its complications in infancy and childhood. J Can Assoc Radiol 20(4):218\u0026ndash;224\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFernandes L, Fernandes Y, Mesquita AM (2016 Nov-Dec) Quantitative computed tomography imaging in chronic obstructive pulmonary disease. Lung India 33(6):646\u0026ndash;652. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.4103/0970-2113.192880\u003c/span\u003e\u003cspan address=\"10.4103/0970-2113.192880\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003ePMID: 27890994; PMCID: PMC5112822\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Columbia University Medical Center","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Swyer-James-MacLeod Syndrome, Hyperlucent Lung, Bronchiolitis Obliterans, High-Resolution Computed Tomography, Case Report","lastPublishedDoi":"10.21203/rs.3.rs-8127642/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8127642/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eSwyer-James-MacLeod Syndrome (SJMS) is a rare, post-infectious obliterative bronchiolitis, typically presenting as a unilateral hyperlucent lung. Bilateral involvement is rare, with only pediatric cases reported to date. This case highlights an unusual bilateral presentation in an adult, which poses a significant diagnostic challenge.\u003c/p\u003e\u003ch2\u003eCase presentation:\u003c/h2\u003e\u003cp\u003eA 30-year-old non-smoking male with a history of recurrent childhood respiratory infections and chronic respiratory symptoms presented with persistent dyspnea. Initial chest radiography was unremarkable, but high-resolution computed tomography (HRCT) revealed bilateral hyperlucent lungs, decreased vascular markings, focal bronchiectasis, and cystic changes. Pulmonary function tests showed an obstructive pattern with a reduced FEV1/FVC ratio (36.79%), increased residual volume (172.6%), and gas trapping. Further workup excluded common differentials like alpha-1-antitrypsin deficiency, cystic fibrosis, and chronic thromboembolic disease. The constellation of findings led to a presumptive diagnosis of bilateral SJMS.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eThis case underscores the radiologic approach to bilateral hyperlucent lung in an adult and a presumptive case of SJMS, a finding previously unreported in the literature. It emphasizes the critical role of HRCT in diagnosis. Recognizing this rare presentation is essential to avoid misdiagnosis and guide appropriate conservative management, preventing unnecessary interventions.\u003c/p\u003e","manuscriptTitle":"Bilateral Hyperlucent Lungs in an Adult: A Radiologic Approach","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-18 08:58:41","doi":"10.21203/rs.3.rs-8127642/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d151966b-fe0a-41da-84fa-263730c18b7e","owner":[],"postedDate":"November 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":58065121,"name":"Pulmonology"},{"id":58065122,"name":"Laboratory Diagnostics"}],"tags":[],"updatedAt":"2025-11-18T08:58:41+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-18 08:58:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8127642","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8127642","identity":"rs-8127642","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}