Chest X-ray Features

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Questions and Answers

What is the maximum transverse diameter of the heart in relation to the maximum transverse diameter of the chest?

50% of the maximum transverse diameter of the chest (correct)

70% of the maximum transverse diameter of the chest

60% of the maximum transverse diameter of the chest

80% of the maximum transverse diameter of the chest

What is the criteria for ensuring a satisfactory chest radiograph has no rotation?

The vertebrae behind the heart are barely visible

The diaphragm can be traced up until reaching the edge of the spine

Medial borders of the clavicle are equidistant from the spinous processes of the vertebral bodies (correct)

Ten ribs visible posteriorly in the mid clavicular line on the frontal chest radiograph

What is the purpose of ascertaining that there are ten ribs visible posteriorly in the mid clavicular line on the frontal chest radiograph?

To confirm that the chest radiograph has no rotation

To confirm that the patient has made a good inspiratory effort (correct)

To confirm that the chest radiograph has good penetration

To confirm that the heart size is normal

What is the effect of gravity on the pulmonary vascular structures?

90% of the pulmonary vascular structures are appreciated at the mid and lower zones Signup and view all the answers

What is the name of the sign that describes the visibility of densities on a radiograph?

The Silhouette Sign Signup and view all the answers

What should be barely visible in an X-ray with good penetration?

The vertebral bodies behind the heart Signup and view all the answers

What is the orientation of the standard chest radiograph where the heart size is measured?

Posterior-Anterior (PA) orientation Signup and view all the answers

How many densities are visible on any radiograph according to Benjamin Felson?

Three densities Signup and view all the answers

What does the disappearance of a normal silhouette imply?

The adjoining area has transmuted into the same density as its neighboring structure Signup and view all the answers

What is the main reason to evaluate the lung apices?

To identify a neoplasm Signup and view all the answers

What is the simplest solution to diagnostic uncertainty in the lung apices?

Request a supplementary apical view Signup and view all the answers

What is the commonest neck mass to displace the trachea?

Thyroid mass Signup and view all the answers

What does the trachea deviated to the contralateral side indicate?

A tension pneumothorax Signup and view all the answers

What is the hilar point on either side of the heart?

The intersection of the pulmonary arteries and veins Signup and view all the answers

What is the significance of the gastric air bubble on the left side?

It is a normal variant Signup and view all the answers

What is the purpose of reviewing the subdiaphragmatic region?

To identify free gas or bowel Signup and view all the answers

What is the normal relationship between the left and right hilar points?

The left hilar point lies higher than the right. Signup and view all the answers

What is the significance of the aorto-pulmonary window?

It is a common site for malignant lymphadenopathy. Signup and view all the answers

Why is bone review important in chest radiographs?

To exclude fractures or dislocations. Signup and view all the answers

What is a feature of cardiac failure in chest radiographs?

Increased cardiothoracic ratio. Signup and view all the answers

What is the principle used to diagnose lobar consolidation?

The silhouette principle. Signup and view all the answers

Which of the following is not a feature of lobar consolidation?

Right heart border Signup and view all the answers

Which pulmonary lobe is associated with the left hemidiaphragm?

Left lower lobe. Signup and view all the answers

What is the significance of the transverse or minor fissure?

It demarcates the right upper lobe. Signup and view all the answers

What is the characteristic of a pneumothorax on an erect radiograph?

Separation of lung edge from the chest wall Signup and view all the answers

What is the characteristic of a pleural effusion on an erect radiograph?

Increased density with a meniscus rising up the lateral chest wall Signup and view all the answers

What is the characteristic of a right upper lobe consolidation?

Consolidation above and terminating at the minor fissure Signup and view all the answers

What is the characteristic of a right middle lobe consolidation?

Consolidation below and terminating at the transverse fissure Signup and view all the answers

What is the characteristic of a left upper lobe consolidation?

Produces a fuzzy 'veiling' effect with consequent reduced conspicuity of the aortic knuckle's silhouette Signup and view all the answers

What is the characteristic of a tension pneumothorax?

Mediastinum is displaced to the contralateral side and there is inferior displacement of the ipsilateral hemidiaphragm Signup and view all the answers

What is the indication of a horizontal fluid level within the chest?

Hydropneumothorax with air in the pleural space Signup and view all the answers

When should an expiratory view be requested?

When there is a clinical suspicion of pneumothorax Signup and view all the answers

Study Notes

Normal Features of a Chest X-ray

A satisfactory chest radiograph should have:
- No rotation, confirmed by ensuring the medial borders of the clavicle are equidistant from the spinous processes of the vertebral bodies.
- Good inspiration, confirmed by ascertaining that there are ten ribs visible posteriorly in the mid clavicular line on the frontal chest radiograph.
- Good penetration, where the vertebrae behind the heart are barely visible, and the diaphragm can be traced up until reaching the edge of the spine.

A System for Reviewing the Chest Radiograph

Check for AP or PA orientation
Evaluate the heart size:
- The maximum transverse diameter of the heart should not exceed 50% of the maximum transverse diameter of the chest on a standard posteroanterior (PA) radiograph.
- This measurement is known as the Cardiothoracic Ratio.
Assess pulmonary vascularity:
- Pulmonary venous vessels should not be discretely visible in the outer third of the lung fields.
- Approximately 90% of the pulmonary vascular structures are appreciated at the mid and lower zones due to the effect of gravity.
Review the lung fields:
- The Silhouette Sign: only three densities are visible on any radiograph (bone, air, and soft tissue).
- The diaphragm and heart borders are adjacent to lung lobes.

Review Areas

Subdiaphragmatic region:
- No free gas should be present under the diaphragm on an erect chest radiograph.
- A gastric air bubble is frequently seen on the left side, while interposed small or large bowel may occasionally be seen on the right.
The lung apices:
- Evaluating the lung apices can be difficult, particularly in older patients where there is asymmetrical calcification of the costochondral junctions.
- Request a supplementary apical view if there is diagnostic uncertainty or an asymmetry in the apical appearances.
The trachea:
- The trachea should be midline, and any deviation may be due to pathology within the neck or chest.
The hilum:
- The hilar point on either side of the heart represents the intersection of the pulmonary arteries and veins.
- The left hilar point normally lies higher than the right.
- The hila should always be equal in size and density.
The aorto-pulmonary window:
- The reviewer should follow the left edge of the mediastinum from its superior aspect to identify the aortic knuckle and pulmonary artery.
- There should be no convexity or mass within the aorto-pulmonary window.
Bones:
- Review bones for two reasons:
  - Trauma: to exclude fractures or dislocations, particularly at shoulder level.
  - Neoplasia: to exclude infiltration and destruction, particularly in metastatic disease and myeloma.

Common Pathologies

Cardiac Failure:
- Increased cardiothoracic ratio
- Increased (venous) pulmonary vascularity
- Kerley B lines
- Pleural Effusions
- Bat or Angel Wings
Lobar Consolidation:
- The confident and accurate diagnosis of lobar consolidation rests on an understanding of the Silhouette Sign.
- Identify the missing silhouette to determine which pulmonary lobe is affected.
Pneumothorax:
- Divided into simple and tension pneumothorax.
- Tension pneumothorax is diagnosed radiologically when the mediastinum is displaced to the contralateral side and there is inferior displacement of the ipsilateral hemidiaphragm.
- Accompanying clinical distress is also present.
Pleural Effusions:
- Typical appearances on an erect radiograph are those of an area of increased density with a meniscus rising up the lateral chest wall.
- A horizontal fluid level within the chest suggests a hydropneumothorax with air in the pleural space.

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Description

This quiz covers the normal features of a chest X-ray, including the positioning, inspiration, and penetration of the image. Understand the key characteristics of a satisfactory chest radiograph.