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Association of the Severity of Emphysema Based on HRCT Scoring System with Clinical Profile and Pulmonary Function Test Parameters: A Cross-sectional Study |
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Sarita Jilowa, Wezode Wezah, Yashvant Singh, Ajay Chauhan 1. Professor, Department of Radiology, ABVIMS and Dr. RML Hospital, New Delhi, India. 2. Junior Resident, Department of Radiology, ABVIMS and Dr. RML Hospital, New Delhi, India. 3. Senior Radiologist, Department of Radiology, ABVIMS and Dr. RML Hospital, New Delhi, India. 4. Professor, Department of Medicine, ABVIMS and Dr. RML Hospital, New Delhi, India. |
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Correspondence Address : Yashvant Singh, D-II/91, West Kidwai Nagar-110023, New Delhi, India. E-mail: y_ashvant@yahoo.com |
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| ABSTRACT |  | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
: Introduction: Chronic Obstructive Pulmonary Disease (COPD) is commonly observed in middle aged and elderly individuals. Dyspnoea, with or without expectoration, or isolated dyspnoea, is the primary respiratory symptom. Clinical signs, symptoms, and Pulmonary Function Tests (PFTs) are non specific. Chest radiography poorly correlates with disease severity and extent compared to clinical and functional impairment. High-Resolution Computed Tomography (HRCT) has been widely adopted to detect, characterise, and quantify emphysema. HRCT scoring is a useful radiological method for assessing emphysema severity in COPD patients and can provide prognostic information. Aim: To assess the severity of emphysema based on the HRCT scoring system and its association with clinical profile and PFTs. Materials and Methods: The present cross-sectional observational study was conducted in the Department of Radiodiagnosis at Atal Bihari Vajpayee Institute of Medical Sciences and Ram Manohar Lohia Hospital, New Delhi, India. It included 30 clinically diagnosed COPD patients referred for HRCT lung scans from November 1,2018, to March 31, 2020. HRCT assessment was performed at three levels: carina, 5 cm above carina, and 5 cm below carina. The severity of lung parenchyma was evaluated using the “Sakai Scoring Method.” The emphysema score was correlated with clinical profile (duration of illness, COPD severity, smoking, and pack-years smoked) and PFT parameters (FEV1, FEV1/FVC). Results: The mean age of the cases was 60±9.44 years. There was a strong positive linear correlation between the duration of illness (r=0.67, p=0.001) and COPD severity (r=0.452, p=0.02) with HRCT emphysema score. Significant correlation was found between HRCT emphysema score and pack-years smoked (r=0.558, p=0.004). The emphysema score showed an inverse correlation with FEV1 (r=-0.56, p=0.002) but no correlation with Forced Expiratory Volume 1/Forced Vital Capacity (FEV1/FVC) (r=-0.16, p=0.430). Conclusion: The HRCT semi-quantitative scoring system is valuable for the initial assessment of disease severity and is significantly correlated with the PFT parameter FEV1. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Keywords : Carina, Chronic obstructive pulmonary disease, Dyspnoea, High resolution computed tomography | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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DOI and Others :
DOI: 10.7860/IJARS/2023/61780.2943
Date of Submission: Nov 23, 2022 Date of Peer Review: Feb 24, 2023 Date of Acceptance: Apr 29, 2023 Date of Publishing: Nov 01, 2023 AUTHOR DECLARATION: • Financial or Other Competing Interests: None • Was Ethics Committee Approval obtained for this study? Yes • Was informed consent obtained from the subjects involved in the study? Yes • For any images presented appropriate consent has been obtained from the subjects. Yes PLAGIARISM CHECKING METHODS: • Plagiarism X-checker: Nov 25, 2022 • Manual Googling: Apr 24, 2023 • iThenticate Software: Apr 28, 2023 (10%) EMENDATIONS: 6 ETYMOLOGY: Author Origin |
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| INTRODUCTION |
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Chronic Obstructive Pulmonary Disease (COPD), described by the Global Initiative for Obstructive Lung Disease (GOLD), is a disease characterised by irreversible airway obstruction and ranks 5th in global disease burden according to the World Health Organisation (WHO) (1),(2). COPD encompasses several overlapping obstructive syndromes, including emphysema, chronic bronchitis, and small airway disease [3,4]. Airflow obstruction in COPD can result from lung parenchymal destruction (emphysema), airway narrowing, or both factors. Emphysema is a progressive disease that leads to breathlessness, chronic cough, sputum production, and systemic effects. Lung function decline occurs due to emphysema and small airway narrowing, resulting in air trapping, progressive airflow limitation, and exertional dyspnoea. The Medical Research Council (MRC) dyspnoea scale is a valid tool for measuring dyspnoea and assessing functional status and severity (5). Impaired lung function growth during early years and adolescence, caused by factors such as infection, allergens, tobacco smoking, and genetic susceptibility, increases the risk of COPD (6),(7). Tobacco smoking is a significant risk factor for COPD, with longitudinal studies showing a dose-response relationship between smoking intensity (in pack-years) and FEV1 decline (8). However, approximately 10% of clinically diagnosed COPD cases globally are non smokers, a proportion that is higher in Indian women due to biomass fuel exposure (8). COPD is now recognised to have systemic consequences beyond the lungs. Spirometry, a common tool for assessing airway obstruction, allows for a simple, repeatable, non invasive, and cost effective global assessment of functional changes. Parameters such as FVC, FRC, and FEV1 are used. COPD is diagnosed when the FEV1/FVC ratio is lower than 70% (9), but this does not provide information about the underlying pathology or the distribution of emphysema (10),(11). Pulmonary Function Tests (PFTs) offer a convenient means of screening and assessing the progression of lung disease (12). However, FEV1 alone cannot capture the heterogeneity of the disease. Peak oxygen uptake (Peak VO2) from cardiopulmonary exercise testing and the distance walked during the six Minute Walk Test (MWT) are employed to assess response to therapeutic interventions and track disease progression (13). Chest radiography lacks specificity for different COPD types, providing non specific findings. HRCT overcomes the limitations of chest radiography and offers more detailed information (14). The HRCT permits detailed anatomical examination of pulmonary structure and is widely used to detect, characterise, and quantify emphysema. It has been used to categorise COPD patients into two main groups: those with emphysema-predominant disease and those with airway-predominant disease (15). Differentiation between these two groups is important because the management strategies differ i.e., lung volume reduction surgery may be effective for patients with emphysema-predominant COPD, while medical treatment is more appropriate for those with airway-predominant COPD (16). Several studies have shown that CT is valuable in quantifying disease severity in COPD, using visual or quantitative CT techniques (17),(18). HRCT provides information about the severity and extent of the disease process and can be quantified using a numerical score (19),(20). Qualitative assessment of emphysematous changes correlates well with airflow obstruction, while objective measures of airway wall thickening also correlate with pulmonary function (21),(22),(23),(24). A higher CT-emphysema score is associated with a poor prognosis in patients with advanced squamous cell lung cancer, and higher mortality from pneumonia is observed in patients with a higher CT-emphysema score (25). There is limited research on HRCT scores for assessing the severity of emphysema in COPD in the Indian setting. Therefore, present study was undertaken to assess the severity of emphysema using HRCT scoring and to examine the correlation between HRCT scores, non invasive PFTs (FEV1 and FEV1/FVC), and clinical profile. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Material and Methods |
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The present cross-sectional observational study was conducted in the Department of Radiodiagnosis at Atal Bihari Vajpayee Institute of Medical Sciences and Dr. Ram Manohar Lohia Hospital, New Delhi, India. from November 1, 2018, to March 31, 2020. The study received approval from the institutional Ethics Committee (no.TP(MD/MS)(80/2018)/IEC/PGIMER/RMLH/913). A total of 30 patients with a clinical diagnosis of COPD were included in the study. Sample size calculation: The sample size was calculated using the formula N={(Zα+Zβ)/C}^2+3, where Zα represents the standard normal deviate for α (1.96), Zβ represents the standard normal deviate for β (0.842), and C represents 0.5*{(1+r)(1-r)}. The calculated sample size was 29.02. Inclusion criteria: Patients of any age and sex who presented with dyspnoea, were referred for HRCT scan of the chest, met the clinical severity criteria for COPD according to GOLD, and were willing to undergo HRCT, were included. Exclusion criteria: Patients with acute exacerbation of COPD were excluded from the study. Study Procedure The severity of dyspnoea was graded from 1 to 5 according to the MRC dyspnoea scale (Table/Fig 1). A thorough clinical history was taken, including symptoms such as dyspnoea, cough with or without expectoration, fever, malaise, chest pain, and smoking. The duration of clinical symptoms and smoking history were also recorded. Pulmonary function test (PFT) reports, including FVC, Functional Residual Capacity (FRC), and FEV1, were collected from records or the respiratory laboratory. The GOLD system was used to categorise patients into mild (GOLD 1), moderate (GOLD II), severe (GOLD III), and very severe (GOLD IV) airflow limitation categories based on PFT findings. Chest X-rays were studied for the presence of any radiological abnormalities. HRCT of the chest was performed for all cases. The procedure and objectives of the HRCT scan were explained to the patients, and written consent was obtained. The 2patients were instructed on breath-holding during the acquisition of scans. The scans were acquired in the supine position, in the cephalocaudal direction from the apex to the base in axial planes. A 128-slice Computed Tomography (CT) scanner (Siemens “Somatom Definition Flash”) was used with the following acquisition protocol: collimation=1 mm, feed=10 mm, kVp=120-140, mA=240, matrix size=512×512, scan time=1 sec, and window level (mean)/width values=-600 to -700/1000 to 1500. After image acquisition, the HRCT scan was assessed at three levels: the level of the carina, 5 cm above the carina, and 5 cm below the carina. The lung parenchyma was graded and scored separately for both the left and right lungs, resulting in a total of six lung fields. The severity score of lung parenchyma was assessed using the Sakai Scoring Method, as explained in (Table/Fig 2). The final emphysema score for each lung field was calculated as Severity x Extent. The sum of the total emphysema scores in both lung fields ranged from 0 to 72 (considering a maximum grade of 3 and a maximum score of 4 for six lung fields). Statistical analysis was used to correlate the HRCT emphysema scoring (dependent variable) with clinical parameters (duration of illness, COPD severity, smoking, number of pack-years smoked) and PFT parameters (FEV1, FEV1/FVC). The outcomes studied included lobar emphysema distribution and emphysema score, gender association with pack-years smoked, PFT, and HRCT emphysema score, PFT and HRCT score parameters, and HRCT emphysema score versus clinical features (dyspnoea). Statistical Analysis The statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 22.0. Categorical variables were presented as numbers and percentages (%), while continuous variables were presented as mean±Standard Deviation (SD). Student’s t-test and one-way Analysis of Variance (ANOVA) followed by a post-hoc test (Tukey’s) were used to compare quantitative variables. Chi-square or Fisher’s-exact test was used to compare qualitative variables. A p-value <0.05 was considered statistically significant. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Results |
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The mean age of the cases was 60±9.44 years (range: 42-80 years). The study included 21 (70%) male and 9 (30%) female patients. The average duration of COPD was two years (ranging from 1 month to 7 years). Dyspnoea was the main presenting symptom in all patients, with other reported symptoms including chronic cough (26%), cough with expectoration (23%), fever (13%), and wheezing (10%). Malaise and chest pain in 6.6% of patients. Among the 30 study patients, 46.7% were current smokers, 20% had a history of smoking cessation, 23.3% were non smokers, and 10% were occasional smokers. Physical examination revealed tobacco staining on teeth in 20% of patients, while clubbing of nails, barrel-shaped chest, and hepatomegaly were noted in 6.6% patients. Cervical lymphadenopathy was observed in 3.3% of patients. The majority of patients (76.7%) in present study were in dyspnoea Grade I and Grade II according to the MRC breathlessness scale (Table/Fig 3). However, according to the GOLD classification, which is based on FEV1 and FEV1/FVC, 27 patients were analysed as 3 patients could not perform PFT. The majority of patients (63.33%) were in the moderate and severe stages (Table/Fig 4). No abnormality was seen on chest X-ray in 14 (46.7%) patients. Hyperinflated lung was seen in 4 (13.3%), whereas fibrotic opacities were noted in 3 (10%) patients (Table/Fig 5). Chest X-rays showed no abnormality in 46.7% of patients, hyperinflated lungs in 13.3% of patients, and fibrotic opacities in 10% of patients. Upper lobe predominance of emphysema was observed in 70% of patients. The mean HRCT score was 25 in patients with upper lobe predominance, while patients with both upper and lower lobe involvement had a mean score of 48 (Table/Fig 6). FEV1/FVC scores ranged from 47 to 79, with an average of 67 points. FEV1 scores ranged from 23 to 90, with an average of 49 points (Table/Fig 7). The HRCT scores of clinical cases showed various types and distributions of emphysema, with corresponding total scores indicating the severity of lung changes (Table/Fig 8),(Table/Fig 9),(Table/Fig 10),(Table/Fig 11),(Table/Fig 12),(Table/Fig 13),(Table/Fig 14). There was a significant difference in FEV1 scores between male and female patients, with male patients being more severely affected (average of 44.4±17 points) compared to female patients (average of 60.75±16.47 points) (Table/Fig 15). Smoking history and HRCT score showed a strong positive correlation, indicating that as smoking history increases, the HRCT score also increases (r=0.500, p=0.011). There was also a strong positive linear correlation between the duration of disease and HRCT score (r=0.67, p=0.001) (Table/Fig 16). The mean HRCT emphysema score in all patients was 30.43±18, with higher scores observed in patients with more advanced stages of COPD based on GOLD classification (37.2±23.5 in COPD GOLD stage 4, 40.4±13.7 in COPD GOLD stage 3, p<0.01) (Table/Fig 17). There was a statistically significant difference in the mean scores of HRCT emphysema among patients with different grades of dyspnoea (p=0.001) (Table/Fig 18). | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Discussion |
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The mean age of the patients in present study was 60 years, with a range of 42 to 80 years. There was a male preponderance, comprising 70% of the total cases. This is consistent with previous studies by Kaya L et al., and who also found a similar age distribution and male preponderance (26). Dyspnoea was gradually progressive in all patients in the study, which is in line with findings by Tel et al., and Sharma et al., who established a correlation between dyspnoea and the duration of COPD (27),(28). Physical examination findings were normal in 50% of cases, supporting the notion that physical examination alone is not sensitive in the initial diagnosis of COPD, as shown in a study by Badgett RG et al., (29). The study also found that non smokers can develop COPD due to household air pollution/biomass fuel exposure, which is in agreement with a study by Salvi SS and Barnes PJ (30). A positive correlation was found between HRCT emphysema score and smoking, as well as the number of pack-years smoked. This is consistent with studies conducted by Kim et al., Patel et al., and Sashidhar et al., (31),(32),(33). The study found an inverse correlation between FEV1 and HRCT emphysema score, which is in line with previous studies by Kaya et al., and Sariaydin et al., (26),(34). However, no significant correlation was found between FEV1/FVC and HRCT emphysema score in present study. Chest X-ray sensitivity was found to be low, consistent with studies by Thurlbeck and Simon and Klein et al., (35),(36). The distribution of emphysema in present study showed upper lobe predominance, similar to a study by Gurney et al., (37). The mean visual emphysema score in all patients was comparable to the findings of Kaya et al., (26). The study found that an increase in HRCT emphysema score was associated with decreased lung function, particularly FEV1. This is consistent with the study by Sariaydin et al., Additionally, there was a positive correlation between COPD severity and HRCT emphysema score in present study (34). The correlation between HRCT emphysema score and parameters of pulmonary function testing suggests that the visual scoring method can be used as an initial assessment of emphysema severity. However, there was no significant relationship found between clinical grades of dyspnoea and HRCT emphysema scores in the literature. Limitation(s) Limitations of present study include a small sample size with a predominance of male participants and a focus on patients with moderate to severe obstructive features seeking treatment. Therefore, the findings may not be generalisable to patients with emphysema and preserved lung function. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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