X-Ray Interpretation Lecture 2

Study Notes

Chest X-Ray is a frequently requested plain radiograph, but can be difficult to interpret. A systematic approach is crucial.
Indications include infectious, inflammatory, or neoplastic lung pathologies, chest trauma (hemothorax, rib fracture), COPD, ILD, and cardiac pathologies.

PA: Standard view.
Lateral: Localizes abnormalities seen in the PA view.
AP, Supine: Useful for infants and ill patients, but not ideal for assessing heart size.
Erect: Detects gas under the diaphragm.

Oblique: Demonstrates pleural chest wall and rib abnormalities.
Apical: Provides a clear view of lung apices, free of bone.
Expiratory: Highlights air trapping and pneumothorax.
Lateral Decubitus: Aids in identifying small pleural or subpulmonic effusions.

Patient Information: Request forms should include name, age, sex, date, MRN, and pertinent clinical details.
Technical Factors: Centring, patient position, marker, exposure, and degree of inspiration are critical for accurate interpretation.
Good inspiration: At least 10 posterior and 6 anterior ribs should be visible. The base of the lungs should be clearly defined. Poor inspiration can cause a normal-sized heart to appear enlarged.
Centring: Spinous processes and medial ends of clavicles align with the image.
Penetration: Bodies of 1-4 thoracic vertebrae should be visible.

Trachea: Position and outline are evaluated.
Heart and Mediastinum: Shape, relative position, and any abnormalities are noted.
Diaphragm: Outline, shape, and relative position are assessed.
Pleura: Horizontal fissure positioning, and costophrenic/cardiophrenic angles should be reviewed.
Lung Fields: Local or generalized abnormalities, translucency, and vascular markings are observed.
Hidden Areas: Apices and posterior sulci receive attention for any abnormalities.
Hilum: Density, position, and shape are notable.
Below Diaphragm: Gas, shadows, calcification, and soft tissue densities(e.g., mastectomy).

Air Space Disease: Involves filling of air spaces with fluid, exudate, blood or edema, causing opacity. Silhouette sign is typical of the loss of border definitions between structures like mediastinum, diaphragm, vs. adjacent lung.
Atelectasis: Volume loss in a portion of the lung (e.g., lobe, segment or subsegment). It can be massive (entire lung) or less extensive. Different types include obstructive, passive, and compressive.
Masses: Opacities suggesting cancer (primary bronchogenic carcinoma), metastasis, lymphoma, or chest wall/mediastinal tumors
Pleural Effusion: Abnormal fluid collection. Radiographic signs include homogenous opacification, loss of diaphragm outline and no visible pulmonary/bronchial markings. Identifying the meniscus sign (concave upper border).
Pneumothorax: Air in the pleural cavity. Radiological signs include absent lung markings, and mediastinal shift (tension pneumothorax).
Hydro Pneumothorax: Air and fluid in pleural cavity, usually related to bronchial-pleural fistula.
Rib Fractures: Commonly involve the 4th-10th ribs. Fractures of the 1st-3rd ribs are often associated with high-energy trauma. A flail chest can occur with three or more contiguous ribs in at least two places fracturing and resulting in rib floating.
Clavicle Fractures: Common (5% of all fractures), typically in the mid-shaft.

Tuberculosis (TB) can present in primary or secondary forms in an x-ray.
Primary TB usually occurs in children and may present as consolidation or lymphadenopathy.
Secondary TB presents in adults, often with cavitary lesions, pleural effusion, and possible lymphadenopathy.
Miliary TB involves hematogenous dissemination of the bacilli and presents with millet-sized nodules.

Podcast