An Assessment of Tracheal Index and Thoracic Cage Ratio in patients with Chronic Obstructive Pulmonary Disease
DOI:
https://doi.org/10.70192/Keywords:
COPD, HRCT, Tracheal index, Thoracic cage ratio, Lung hyperinflation, Saber Sheath Trachea, Airways disordersAbstract
Introduction: Chronic obstructive pulmonary disease is a heterogeneous lung condition characterized by chronic respiratory symptoms due to abnormalities of the airways and/or alveoli that cause persistent, often progressive, airflow obstruction.
Objectives: The present study was undertaken to assess the tracheal index and the thoracic cage ratio in patients with COPD.
Methods: Male COPD patients diagnosed in accordance with GOLD guidelines were included; all study subjects had with smoking history of ≥ 20 pack years and age ≥ 40 years. Patients who had any evidence of coexisting lung disease other than COPD were excluded. Patients having comorbid systemic disorders were also excluded. High-resolution CT scans were obtained without using any contrast. Tracheal Index, defined as the ratio of transverse/anteroposterior diameter at a plane 1-cm above the aortic arch, was analyzed. A tracheal index is < 0.67 was considered as Saber-sheath trachea. In the present study, the thoracic cage ratio was evaluated at two planes: carina and 5 cm below the carina.
Results: A total of 40 COPD patients completed the study. Their mean age was 59.86 ± 9.46 years. Mean smoking history of 37.67 ± 12.26 pack years. Total duration of illness due to COPD was a mean of 14.58 ± 4.86 years. Their FEV1/FVC ratio varied from 0.49 to 0.66 and the resting oxygen saturation was 87.6 to 95.6%. Saber Sheath Trachea was assessed in 14 patients, thoracic cage ratio > 0.75 at Carina was seen in 5 patients, and Thoracic Cage Ratio > 0.75 at 5 cm below Carina was found in 11 patients. Tracheal Index had significant correlations with age, duration of illness, pack years and FEV1/FVC Ratio. Thoracic Cage Ratio at carina and that 5 cm below carina had significant correlations with age, duration of illness, pack years and FEV1/FVC Ratio
Conclusion: HRCT was observed to be a useful imaging modality to detect characteristics of pulmonary hyperinflation – Tracheal index and the thoracic cage ratio. These parameters had significant correlations with the severity of the disease.
