The Chest X-Ray: A Survival Guide

Gerald de Lacey, Simon Morley, Laurence Berman

• Publisher: Saunders Ltd.
• Year: 2012
• eBook ISBN: 9780702051074
• Topic: Medicine
• Subtopic: Radiology, Radiotherapy & Nuclear Medicine

British Medical Association Book Awards 2009 - First Prize Winner, Radiology CategoryFeaturing a practical, clinical approach – and written in a quick-access style – this portable, economical reference helps you build a strong foundation in chest x-ray interpretation. Three radiologists with years of clinical and teaching experience present fundamental principles and key anatomical concepts…walk you through examples of classic chest x-ray features that provide subtle evidence of abnormality…and explore a variety of problems and dilemmas common to everyday clinical practice. High-quality drawings and digital chest x-rays – combined with secrets from the radiologists' toolbox, helpful differential diagnoses, handy checklists, and key references – deliver all the assistance you need to enhance your interpretation skills.- Provides a strong foundation of essential knowledge for an informed, systematic approach to accurate chest x-ray interpretation.- Features the work of three radiologists who offer you the benefit of their many years of clinical and teaching experience.- Emphasizes common errors and misdiagnoses to help ensure correct image readings.- Presents step-by-step guidance in a bulleted, quick-access format, in short chapters focused on clinical problems, to make it easy to master the information that you need to know.- Makes difficult anatomic concepts easier to grasp by pairing radiographs with color line drawings.- Explains the nomenclature special to the field through a glossary of important terms.- Highlights the most important concepts in diagnosis/interpretation via Key Points in each chapter.

Part A

Core Knowledge

1 CHEST RADIOLOGY: THE BASIC BASICS

You will need a basic understanding of some of the technical factors affecting chest radiography, if only to recognise when a particular appearance arises not from pathology but from suboptimal technique. This chapter concentrates on the frontal CXR. We discuss the lateral CXR in Chapter 2.

THE RADIOGRAPHIC IMAGE

Table 1.1 Attenuation of the x-ray beam.

Tissue absorption		Effect on the radiograph (see Fig. 1.1)
Least	Air or gas	Black image
	Fat	Dark grey image
	Soft tissue	Grey image
Most	Bone or calcium	White image

THE FRONTAL CXR

This standard CXR is obtained at a fixed distance between the x-ray tube and the cassette of 180 cm (6 ft). The patient faces the cassette and the x-ray beam passes through in the posterior to anterior direction, i.e. PA (Fig. 1.2).

Figure 1.1 Normal PA CXR. Standard radiographic technique allows comparison of the heart size on any previous or subsequent PA CXR.

Figure 1.2 Patient positioning for a standard PA CXR. The 180 cm (6 ft) x-ray tube to cassette distance results in a beam that is minimally divergent. In effect, the x-rays are parallel when they impact on the thorax.

The PA CXR is preferred because the radiographic technique is standard. This allows accurate and valid comparison between repeated PA CXRs.

If the patient is unable to stand erect then he faces the x-ray tube and an antero–posterior (AP) chest radiograph is obtained. AP CXRs are acquired:

At the bedside or with a seriously ill or frail patient in the emergency department. The patient may be lying supine (Fig. 1.3) or sitting up.

In the radiology department when the patient is either too frail or too unsteady to stand erect. The radiographer (technologist) sits the patient ona chair with his back to the cassette (Fig. 1.4).

Figure 1.3 Bedside (i.e. portable) radiograph, patient supine. AP CXR. The distance from the x-ray source to the cassette is much less than 180 cm (6 ft).

Figure 1.4 Frail patient. Departmental radiograph, patient sitting up. AP CXR.

THE BEDSIDE (PORTABLE) AP CXR HAS DISADVANTAGES

The AP CXR should always be interpreted with caution (Fig. 1.5). The following factors may cause misleading appearances:

The mediastinum is magnified (Figs 1.6 and 1.7).

When lying supine a patient is often unable to take a full inspiration. Also, he may...

Table of contents

• Cover
• Title Page
• Front Matter
• Copyright
• PREFACE
• ACKNOWLEDGEMENTS
• REFERENCE: NORMAL CXR
• Table of Contents
• Part A: Core Knowledge
• Part B: Clinical Problems
• INDEX