Chest X-ray in Tuberculosis: A Guide to Interpretation

Chest X-ray in Tuberculosis: A Guide to Interpretation

This article will provide basic information on how to interpret chest X-rays in the diagnosis of pulmonary tuberculosis.

1. Signs on the X-ray:

• Signs of Hilum Opacity:

• Opacity obscures the hilum but the vessels behind the opacity are still visible.

• Found in cases of lymph node inflammation, mediastinal tumor.

• Signs of Hilum Convergence:

• Vessels converge in front of the opacity.

• Commonly found in vascular diseases.

• Difference between upright and recumbent films:

• Recumbent film: X-rays pass from front to back, unable to evaluate the width of the mediastinum.

• Upright film: X-rays pass from back to front, allowing for evaluation of the width of the mediastinum (wide mediastinum, no air shadow, enlarged heart shadow).

• Comparison between right and left oblique films:

• Lesions on the side are tilted towards that side.

• Two hemidiaphragms are parallel: Right tilt.

• Two hemidiaphragms intersect: Left tilt.

• Digital film technical standards:

• Films are neither too hard nor too soft.

• Pulmonary vessels behind the diaphragm and behind the heart are clearly visible.

• Order of film interpretation:

• Heart, pulmonary vessels, mediastinum, hilar regions on both sides, both lungs, cavity areas, lines in the lungs, pleural space, bones and chest wall.

2. Cavity areas:

• Behind the heart, behind the hilar region, behind the diaphragm, lung apex.

3. Common TB lesions:

• Active stage:

• Nodule: Round or oval opacity, well-defined border, high density.

• Infiltration: Dense opacity, uneven density, unclear borders, area > 1cm.

• Cavity: Circular or oval lucency, closed border, appearing in the middle of a homogeneous opacity or surrounding it.

• Late stage:

• Fibrosis: Linear shape, pulling on the trachea, bronchi, heart, mediastinum, diaphragm.

• Calcification: Usually seen in nodules, infiltration, old cavities.

4. Post-TB treatment sequelae:

• Post-TB bronchiectasis with hemoptysis.

• Fungal ball (recurrent cough).

• Lung cancer (on top of higher lesions).

• COPD (Chronic Obstructive Pulmonary Disease).

5. Differentiating lesions:

• Solitary nodule:

• Cancer, arteriovenous malformation, TB nodule, benign lung tumor, lung fluke, round pneumonia.

• Reticulonodular syndrome:

• Miliary TB, congestive heart failure, interstitial pneumonia, fungal pneumonia, pneumoconiosis.

• Miliary TB: 3 uniformities (density, size, distribution).

• Infiltration:

• Oval shape, cloudiness, triangular shape.

• Upper lobe predominance.

• New cavity:

• Thick wall, irregular border, surrounded by infiltration.

• Old cavity:

• Thin wall, fibrosis around, retraction.

• Differentiating cavity from air cyst:

• Pneumothorax, air cyst.

• COPD:

• Two forms: Blue bloater (obese, large, pale lips) and pink puffer (thin, pink lips, pursed lips breathing).

• Fibrosis, calcification:

• Linear shape, pulling on the trachea, bronchi, heart, mediastinum, diaphragm.

• Pleural effusion:

• Homogenous opacity in the lung base, loss of costophrenic angle, displacement of the heart and mediastinum.

6. Localized effusion:

• Differentiate from lung collapse.

7. Damaseau’s curve:

• Principle: Negative pressure in the pleural space, surface tension of pleural fluid.

• Hyperpol appearance.

• Conditions: Moderate effusion, upright position, free effusion, fluid permeation.

• Significance: Free fluid, exudate, moderate.

8. Pneumothorax:

• Image of excessive lung opacity, loss of lung markings, lung tissue retracts towards the center, visible visceral pleural line.

• Mediastinum shifts to the opposite side, diaphragm lowers, bronchi dilate.

9. Classification of pneumothorax severity:

• Minimal: No intervention required (only oxygen therapy, spontaneous resorption).

• Extensive: Thoracentesis …

10. Three characteristics of TB lesions on X-rays:

• Upper lobe predominance.

• Polymorphic lesions.

• Slowly progressing lesions.

11. TB lesion classification:

• Grade 1: No cavity, combined width of lesions does not exceed the horizontal line through the 2nd costosternal joint.

• Grade 2: Scattered, total area does not exceed 1 lung, if lesions are connected, no more than 1/3 of 1 lung, if there is a cavity, total diameter of the cavities < 4cm.

• Grade 3: Exceeds Grade 2.

Note: This article is intended only to provide basic information on interpreting chest X-rays in the diagnosis of pulmonary tuberculosis. For accurate results, consult a specialist doctor.