AFAMS Residency Orientation April 16, 2012 Basics of Chest X-Ray AFAMS Residency Orientation April 16, 2012

Outline CXR Basics Types of CXR Obtaining Images PA vs. AP Films Obtaining Images Systematic method to reading CXR Common Signs Examples

Chest X-ray (CXR) Basics A standard chest X-ray consists of a PA Image Lateral Image Images read together AP for supine patients Lots of information available on a CXR Be systematic with your reading Always compare to prior studies if possible

Basics of X-Rays X-Rays are part of the light spectrum Unlike visible light, x-rays pass through the human body Pass through lungs without much interference Difficult to pass through bones Place film cassette on other side of patient and capture the shadow

Basics of X-Ray Organs absorb X-rays differently and thus their shadow on the film is different Bone: high absorption (film appears white) Tissue: moderate absorption (film appears grey) Air/Lungs: little absorption (film appears black)

Types of CXRs PA and Lateral Supine AP Patient facing cassette X-ray 6 feet away Supine AP X-ray 40 inches away Magnifies anterior structures and pulmonary vasculature 101 cm 1.83 m

Comparing Chest X-rays Protocols AP Preferred method Note heart enlarged, lung fields not as clear

PA Image PA Film Read as if patient is facing you (Patient’s left side is on the right of the X-ray)

Lateral Image Obtained with patient’s left side against the cassette. Minimizes heart silhouette magnification

Assessing Film Technique Inspiration Penetration Rotation

Inspiration Image should be at full inspiration Diaphragm at level of 8-10 rib Allows reader to see intrapulmonary structures Poor Inspiration mimics RML Infiltrate Same patient with proper inspiration

Penetration Amount of radiation required for a quality image PA film: should barely see thoracic spine disc spaces Lateral: spine should appear darker as move cadually Examples of adequately penetrated images

Penetration Overpenetrated Underpenetrated

Rotation Patient should be flat against the cassette Rotation of the patient will alter appearance of mediastinum Observe rotation by comparing location of clavicular heads Should be equal distance from spinous process of thoracic vertebral bodies

Rotation Normal Rotated to the Right

Mass vs. Infiltrate Mass Infiltrate

Lobes and Fissures: PA Film A: Minor Fissure between RML and RLL B: Upper and lower boundaries of major fissures

Lobes and Fissures: Lateral B: Major Fissure L Lung A: Minor Fissure R Lung B: Major Fissure R Lung

CXR Anatomy

CXR Anatomy

How to Read an X-Ray Part 1 Patient Data (Name, history, age, sex) Technique (PA vs. AP, rotation, penetration, etc) Trachea: midline or deviated, any masses? Lungs: masses, infiltrates? Costophrenic angles should be sharp (if not = effusions) Silhouette signs, air-bronchograms, pulmonary edema Pulmonary vessels: enlarged?

How to Read an X-Ray Part 2 Hilar Region: masses or lymphadenopathy Heart: enlarged, abnormal shape Pleura: effusion, thickening, calcification Bones: fractures or masses ICU Films: looks for line and tube placement

How to Read an X-Ray Part 3 It is best to focus on a small area of the film and then scan rather than look at the whole film at once

Signs: Silhouette Sign Loss of lung/soft tissue interface caused by mass, fluid, or infiltrate in the normally air filled lung Commonly applied to heart, aorta, chest wall, and diaphram borders with lung Location of silhouette sign helps to localize pathology Lose Right Heart and Lung border = RML

Signs: Air Bronchogram Tubular outline of an airway made visible by filling of the surrounding alveoli by fluid or inflammatory exudates Causes Pulmonary edema Lung Consolidation Severe Interstitial Disease Neoplasm

Signs: Solitary Pulmonary Nodule Can be innocuous or potentially fatal lung cancer Always compare to prior films for growth Nodules with irregular borders are suspicious

Conclusions Lots of information in a chest x-ray Always read the film in the same order Never skip to the most prominent abnormality, you will miss a small (but potentially important finding) Compare to priors if possible We will finish with some examples of common pathology

Examples: Atelectasis Collapse or incomplete expansion of alveoli Causes: Endobronchial lesions (mucous plug or tumor) Extrinsic compression (mass, lymph node) Peripheral compression (pleural effusion) Linear density on CXR

Examples: Pulmonary Edema Cephalization of pulmonary vessels (arrow) Kerley B Lines Peribronchial cuffing “Bat Wing” Appearance Increased Cardiac Size (arrow)

Examples: Pneumonia Airspace disease and consolidation CXR Findings Airspace opacity Lobar consolidation Interstitial opacities

Differentiating Atelectasis from Pneumonia Volume Loss Associated ipsilateral shift Linear, wedge shaped Apex at hilum Air bronchograms Normal or increased volume No shift Consolidation, air space process Not centered at hilum Air bronchograms

Examples: TB TB can be seen as consolidation, cavitation, fibrosis, adenopathy, or pleural effusion depending on stage of infection

Examples: Pleural Effusions Fluid in Costophrenic Angle Blunting of Costophrenic Angles

Examples: Pneumothorax (PTX) Air inside the thoracic cavity but outside the lung PTX appears as air without lung markings in least dependent area of chest

Examples: Hemopneumothorax Lung Air Fluid

Examples: Interstitial Lung Disease Hazy ground glass opacification Volume Loss Linear opacities bilaterally “Honeycomb lung”

Examples: COPD and Emphysema Diffuse hyperinflation Flattened diaphragms Increased retrosternal space Bullae

Examples: Rib Fractures Can you find the rib fracture?

Examples: Pericardial Effusion

Examples: Hiatal Hernia Gastric Bubble

Hilar Enlargement Enlarged Pulmonary Artery Hilar Adenopathy