Imaging Modalities and Pneumonia Overview

Imaging Modalities

• Plain X-rays provide basic lung visualization.
• Computed Tomography (CT) allows for detailed cross-sectional imaging.
• Magnetic Resonance Imaging (MRI) offers soft tissue contrast, useful for complex cases.
• Ultrasound is effective for evaluating pleural pathologies.

X-ray Imaging Views

• Postero-anterior View: Standard view for assessing lung fields.
• Lateral View: Useful for evaluating the depth and extent of lung pathology.

Pneumonia

• Defined as lung consolidation with a lobar distribution.
• Key features include:
  • Opacity confined to a lobe or part of a lobe, limited by fissures.
  • Retained normal lung volume.
  • Presence of air-bronchograms indicating fluid-filled areas surrounding air-filled bronchi.

Lung Collapse (Atelectasis)

• Represents partial or complete loss of lung volume.
• Mechanisms:
  • Obstructive Collapse: Caused by bronchial obstruction (e.g., by tumors or mucus plugs), leading to gas absorption.
  • Non-obstructive Collapse: Results from external compression, such as pleural masses or fluid.
• Direct Signs:
  • Displacement of interlobar fissures, loss of aeration, vascular crowding, and bronchial rearrangement.
• Indirect Signs:
  • Elevated hemidiaphragm, mediastinal shift, rib crowding, and compensatory hyperinflation.

Tuberculosis

• Radiographic features include:
  • Lobar consolidation known as the Ghon's focus in peripheral lung regions.
  • Enlarged lymph nodes and potential pleural effusions.
  • Pneumothorax presence and miliary tuberculosis characterized by multiple small soft tissue opacities.
  • Tuberculoma presenting as solitary pulmonary nodules and severe lung destruction leading to fibrosis and cystic changes.

Emphysema

• Defined by increased size of air spaces distally with wall destruction.
• Radiological Features:
  • Hyperinflation of the lungs and reduced peripheral vascularity.
  • Flattening of the diaphragm, long narrow heart, and presence of bullae.

Bronchogenic Carcinoma

• Radiological features include:
  • Solitary or multiple pulmonary nodules and lung masses.
  • Potential for cavitating masses and mediastinal lymphadenopathy.
  • Pleural thickening or effusion.

Malignant Pulmonary Tumors

• Cavitating squamous cell carcinoma: Notable for its invasive properties.
• Pancoast tumor: Affects the apex of the lung, often causing local symptoms.

Pulmonary Metastasis

• Tends to present as multiple nodules or masses throughout the lung fields.

Pleural Pathology

• Pleural Effusion: Accumulation of fluid (e.g., exudate, blood, pus) in the pleural cavity.
  • Mild effusion-obliterates costo-phrenic angle.
  • Massive effusion involves significant fluid accumulation.
• Pneumothorax: Accumulation of air in the pleural cavity, resulting in increased lucency.
• Hydro-pneumothorax: Presence of both air and fluid, creating an air/fluid level on imaging.
• Pleural Neoplasm:
  • Focal tumors like fibrous tumors, lipomas, and liposarcomas.
  • Diffuse tumors include malignant mesothelioma and metastases.