Bronchiectasis is defined as abnormal and permanent dilatation and distortion of the bronchi with destruction of bronchial wall. It is characterized by irreversible dilatation of the bronchi with chronic productive cough, airway obstruction and recurrent infections. It can be categorized according to the radiographic or pathological appearance of airways as cylindrical or tubular bronchiectasis characterized by dilated airways alone and is sometimes seen as a residual effect of pneumonia, varicose bronchiectasis characterized by focal constrictive areas along the dilated airways that result from defects in the bronchial wall and saccular or cystic bronchiectasis characterized by progressive dilatation of the airways, which end in large cysts, saccules or grape-like clusters[1].

The prevalence of bronchiectasis is found to be more in females than males. Previous history of tuberculosis is one of the major causes for bronchiectasis [2]. Chest radiographic findings are usually nonspecific and may include focal pneumonitis, scattered irregular opacities, linear or plate like atelectasis or specifically dilated and thickened airways that appear as ring-like shadows (of airways that are seen on end) or tram lines (in the case of airways that are perpendicular to the x-ray beam). Documentation of this disease has traditionally relied on bronchography which is rarely performed, and has not taken into account the significant impact that computed tomography had on the diagnosis of Computed Tomography (CT) is a fast, widely available imaging technique that provides a detailed view of the internal organs and structures. The consequent widespread use of computed tomography for evaluation of pulmonary diseases has revealed that mild and moderate forms of bronchiectasis are fairly common, even in patients without clinical or plain radiographic suspicion of bronchiectasis[3]. HRCT has largely eliminated the need for bronchography in the diagnosis of bronchiectasis currently, high-resolution computed tomography (HRCT) is commonly used to grade severity and extent in bronchiectasis [4]. HRCT has allowed visualization of airways and parenchyma in much greater details than conventional CT and plain radiography and has made it possible to assess the site, magnitude, and distribution of airway remodelling.

CT assessment of the degree of anatomical change may reflect clinical and functional limitation caused by bronchiectasis. Specific abnormalities related to bronchiectasis found on high-resolution CT include dilatation of an airway lumen, rendering it more than 1.5 times as wide as a nearby vessel; lack of tapering of an airway towards the periphery; varicose constrictions along airways; and ballooned cysts at the end of a bronchus. Nonspecific findings include consolidation or infiltration of a lobe with dilatation of the airways, thickening of the bronchial walls, mucous plugs, enlarged lymph nodes and reduction in vascular markings similar to that seen in emphysema, probably as a result of the inflammatory destruction of smaller airways and vessels [5]. Hence this study was undertaken to find the role of HRCT in diagnosis, regional distribution and characterize bronchiectasis morphologically.

Study Design and Setting

This hospital-based prospective descriptive observational study was conducted in the Department of Radiodiagnosis, Gadag Institute of Medical Sciences (GIMS), Gadag, Karnataka, among elderly patients referred for High-Resolution Computed Tomography (HRCT) of the chest with a clinical suspicion of bronchiectasis. The study was carried out over a period of 18 months after obtaining approval from the Institutional Ethics Committee. Written informed consent was obtained from all participants prior to enrolment.

Assuming a correlation coefficient of 0.32, with 80% power and a 5% level of significance, the estimated sample size was 60 elderly patients.

Study Population

A total of 60 consecutive elderly patients aged 60 years and above with clinically suspected bronchiectasis who fulfilled the eligibility criteria were included in the study.

Inclusion Criteria

• Patients aged 60 years and above.
• Both male and female patients.
• Patients clinically suspected to have bronchiectasis and referred for HRCT thorax.
• Patients willing to provide written informed consent.

Exclusion Criteria

• Patients aged less than 60 years.
• Pregnant women.
• Patients with a history of previous lung resection.
• Patients unwilling or unable to provide informed consent.

HRCT Technique

All HRCT examinations were performed using a 16-slice GE BRIVO 385 Computed Tomography scanner. Patients were examined in the supine position without gantry tilt. A scout scan was obtained routinely before image acquisition. Scanning was performed from the lung apices to the lung bases during suspended full inspiration.

Images were acquired using a lung window setting with a window width of 1000–1600 HU and a window level of –600 to –700 HU. Thin-section HRCT images were obtained using 1-mm slice thickness at 10-mm intervals, with tube settings of 120 kVp and 120 mA.

HRCT Evaluation

Bronchiectasis was evaluated with respect to its anatomical distribution, extent of disease, and morphological characteristics.

The extent of bronchiectasis was graded separately for each pulmonary lobe according to the percentage of lobar involvement:

• Grade 0 – No involvement
• Grade 1 – Mild (<25%)
• Grade 2 – Moderate (25–50%)
• Grade 3 – Severe (>50%)

Individual lobar scores were summed to obtain the total bronchiectasis extent score for each patient.

Bronchial wall thickness was assessed relative to the external diameter of the dilated bronchus and graded as follows:

• Grade 0 – Normal wall thickness
• Grade 1 – Wall thickness >20% but <50% of external bronchial diameter
• Grade 2 – Wall thickness ≥50% of external bronchial diameter
• Grade 3 – Complete obliteration of the bronchial lumen

Where varying degrees of bronchial wall thickening were present within a lobe, the mean lobar score was calculated.

Small-airway abnormalities including centrilobular nodules, tree-in-bud opacities, and bronchiolectasis were recorded for each lobe as either present (Grade 1) or absent (Grade 0). Individual lobar scores were summed to obtain the total small-airway abnormality score.

Mosaic attenuation was defined as alternating areas of hypoattenuation and hyperattenuation of the lung parenchyma. Presence of mosaic attenuation in each lobe was scored as Grade 1 and absence as Grade 0, with individual lobar scores summed to calculate the total mosaic attenuation score.

Morphological classification of bronchiectasis was recorded as:

• Cylindrical
• Varicose
• Cystic
• Mixed

Additional HRCT findings including bronchial wall thickening, lack of bronchial tapering, bronchoarterial ratio (>1.5), peripherally visualized bronchi, mucus plugging, air-fluid levels, and associated parenchymal abnormalities were documented.

Pulmonary Function Tests

Pulmonary function testing was performed either before or after HRCT evaluation using standard spirometry. The parameters recorded included:

• Forced Vital Capacity (FVC)
• Forced Expiratory Volume in one second (FEV₁)
• FEV₁/FVC ratio

Ethical Considerations

Ethical clearance was obtained from the Institutional Ethics Committee of Gadag Institute of Medical Sciences prior to commencement of the study. Written informed consent was obtained from all participants. Confidentiality of patient information was maintained throughout the study. HRCT chest and pulmonary function tests were performed as part of the routine clinical evaluation of suspected bronchiectasis, and no additional investigations or procedures were performed solely for research purposes. Therefore, participation in the study did not expose patients to any additional risk beyond standard clinical care.

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using IBM SPSS Statistics for Windows, Version 26.0 (IBM Corp., Armonk, NY, USA). Continuous variables were summarized as mean ± standard deviation (SD) and range, while categorical variables were expressed as frequencies and percentages. Descriptive statistics were used to summarize demographic characteristics, HRCT findings, regional distribution, and morphological patterns of bronchiectasis in elderly patients. A p-value <0.05 was considered statistically significant wherever inferential statistical tests were applied.

A hospital-based prospective descriptive observational study was conducted among 60 elderly patients aged 60 years and above who were clinically suspected to have bronchiectasis and referred for HRCT examination.

The mean age of the overall study population was 70.7 ± 8.09 years, with an age range of 60–89 years. The mean age of the male patients was 71.6 ± 8.2 years, while the mean age of the female patients was 70.1 ± 8.0 years.

The maximum number of patients, 24 (40.0%), belonged to the age group of 60–69 years, followed by 22 (36.7%) patients in the age group of 70–79 years and 14 (23.3%) patients aged 80 years and above.

Of the 60 patients, 23 (38.3%) were males and 37 (61.7%) were females, indicating a female predominance.

Table 1. Age distribution of the study participants

The mean age was 70.7 ± 8.09 years, and the age of the participants ranged from 60 to 89 years.

There was predominant lower-lobe involvement in the present study. A total of 202 lobes were affected by bronchiectasis. Of these, 81 (40.1%) were lower lobes, 65 (32.2%) were the right middle lobe or lingula, and 56 (27.7%) were upper lobes.

Table 2. Regional lobar distribution of bronchiectasis

The left lung accounted for 104 of the 202 affected lobes, while the right lung accounted for 98. The lower lobes were affected most frequently, with the left lower lobe showing the greatest involvement.

The posterior basal segment of the left lower lobe was the most commonly affected segment, being involved in 43 (71.7%) patients. This was followed by the medial segment of the right middle lobe in 34 (56.7%) patients.

Table 3. Segmental distribution of bronchiectasis

Unilateral bronchiectasis was observed in 18 (30.0%) patients, while bilateral involvement was noted in 42 (70.0%) patients.

Cylindrical bronchiectasis was the most frequent morphological pattern and was observed in 22 (36.7%) patients. Mixed bronchiectasis was observed in 19 (31.7%), varicose bronchiectasis in 12 (20.0%), and cystic bronchiectasis in 7 (11.7%) patients.

Table 4. Morphological forms of bronchiectasis

Among the diagnostic HRCT findings, peripherally visualized bronchi were the most common and were identified in 49 (81.7%) patients. Lack of normal bronchial tapering was noted in 45 (75.0%) patients, while bronchial wall thickening was observed in 43 (71.7%) patients.

A bronchial-to-pulmonary artery ratio greater than 1.5 was present in 38 (63.3%) patients. Air-fluid levels or dilated mucus-filled bronchi were observed in 24 (40.0%) patients.

Table 5. HRCT findings among elderly patients with bronchiectasis

As more than one HRCT finding could be present in the same patient, the percentages in Table 5 are not mutually exclusive.

The present study evaluated the role of HRCT in diagnosing and characterizing bronchiectasis among 60 elderly patients aged 60 years and above. The participants ranged in age from 60 to 89 years, with a mean age of 70.7 ± 8.09 years. The largest proportion of participants belonged to the age group of 60–69 years.

Bronchiectasis in elderly patients may be associated with age-related impairment of mucociliary clearance, reduced cough effectiveness, recurrent respiratory infections, previous pulmonary tuberculosis, chronic obstructive pulmonary disease, aspiration, and immune dysfunction. These factors may contribute to persistent airway inflammation, bronchial wall damage, and irreversible bronchial dilatation.

Female predominance was observed in the present study, with females accounting for 61.7% of the participants and males accounting for 38.3%. This distribution was comparable to the female predominance described in earlier studies, including that of Ooi et al.[6].

HRCT permits accurate lobar and segmental localization of bronchiectasis and provides detailed information regarding disease extent, morphology, and associated parenchymal abnormalities. In the present study, a total of 202 lobes were involved. Lower lobes accounted for the largest proportion of affected lobes, representing 40.1% of all involved lobes.

The left lower lobe was affected more frequently than the right lower lobe. The posterior basal segment of the left lower lobe was the most frequently affected segment and was involved in 71.7% of patients. This finding was consistent with previous observations that the left lower lobe and its posterior basal segment are common sites of bronchiectatic involvement.

The predominance of lower-lobe bronchiectasis may be related to the relatively dependent position of the lower lobes, impaired drainage of secretions, recurrent aspiration, and repeated infections. These factors may be particularly relevant in elderly patients because of reduced mobility, swallowing dysfunction, gastro-oesophageal reflux, and impaired cough reflex.

Bilateral bronchiectasis was observed in 70.0% of the study participants, while unilateral disease was present in 30.0%. The high frequency of bilateral involvement suggests that bronchiectasis in elderly patients frequently represents a chronic and relatively extensive airway disease rather than a localized abnormality.

Cylindrical bronchiectasis was the most common morphological form and was identified in 36.7% of patients. It was followed by mixed bronchiectasis in 31.7%, varicose bronchiectasis in 20.0%, and cystic bronchiectasis in 11.7%. Similar findings were reported by Reiff et al.[8], who also observed cylindrical bronchiectasis as a common morphological pattern.

Cylindrical bronchiectasis is characterized by uniform dilatation of the bronchial lumen without normal tapering. Varicose bronchiectasis demonstrates alternating areas of bronchial dilatation and narrowing, whereas cystic bronchiectasis is characterized by severe saccular dilatation of the bronchi. Mixed bronchiectasis refers to the presence of more than one morphological pattern in the same patient.

The bronchoarterial ratio represents the ratio of the internal diameter of a bronchus to the diameter of its accompanying pulmonary artery at the same branching level. An increased bronchoarterial ratio produces the characteristic signet-ring appearance on HRCT and is an important diagnostic feature of bronchiectasis.

In the present study, a bronchial-to-pulmonary artery ratio greater than 1.5 was identified in 63.3% of patients. However, interpretation of the bronchoarterial ratio should consider variations related to age, altitude, pulmonary vascular calibre, hypoxia, and the orientation of the bronchovascular bundle.

Lack of normal bronchial tapering is another important HRCT feature, particularly in patients with cylindrical bronchiectasis. Normally, the bronchial lumen gradually decreases in diameter toward the lung periphery. Persistence of an unchanged bronchial diameter for more than approximately 2 cm distal to a branching point supports the diagnosis of bronchiectasis.

Lack of bronchial tapering was observed in 75.0% of patients in the present study. This was comparable to the findings reported by Kang et al.[13], who documented lack of bronchial tapering in approximately 79% of patients.

Bronchi are generally not visualized within the peripheral 1–2 cm of the normal lung because their walls are too thin to be detected. In bronchiectasis, bronchial dilatation, wall thickening, and peribronchial fibrosis make peripheral bronchi visible on HRCT.

Peripherally visualized bronchi were observed in 81.7% of patients and represented the most common HRCT finding in this study. Bronchial wall thickening was found in 71.7%, while air-fluid levels or dilated mucus-filled bronchi were observed in 40.0%.

These findings demonstrate the usefulness of HRCT in detecting both direct signs of bronchiectasis, including bronchial dilatation and lack of tapering, and indirect signs such as bronchial wall thickening, mucus plugging, and peripheral bronchial visualization.

HRCT is the imaging modality of choice for confirming the diagnosis and evaluating the regional distribution and morphological characteristics of bronchiectasis in elderly patients aged 60 years and above.

Bronchiectasis in the elderly was more frequently bilateral than unilateral, and the lower lobes were affected more commonly than the upper lobes. The posterior basal segment of the left lower lobe was the most frequently involved segment.

Cylindrical bronchiectasis was the most common morphological pattern, followed by mixed bronchiectasis. Peripherally visualized bronchi were the most frequent HRCT finding, followed by lack of bronchial tapering, bronchial wall thickening, and an increased bronchial-to-pulmonary artery ratio.

HRCT provides accurate information regarding the presence, anatomical extent, segmental distribution, and morphological subtype of bronchiectasis and may assist in treatment planning and further clinical management of elderly patients.

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