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10/2/2014
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Chest Radiology:A Systematic Approach
Brian Wetzel ACNP
Senior Instructor
OHSU School of Medicine
Department of Emergency Medicine
Objectives
•A systematic approach to evaluating CXRs
•Identifying common pathology
•Accurately identifying several “can’t miss” findings
Basic Principles
• Plain‐film radiographs
– Depends on differences in radiographic density
• Air
• fat
• Tissue (water)
• Metal (bone)
– Border sharp & well defined
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CXR: why get one?
• CXR is helpful in selected patients
– Dyspnea
– Cough
– Hemoptysis
– Fever
– Chest pain
– Thoracic trauma
CXR: why get one?
• Clinical decision rules developed to predict positive predictors
• Absence of fever, tachycardia, tachypnea, adventitious breath sounds decrease the likelihood of infiltrate to <1%
• Use clinical judgment
(Gennis, et al. Clinical criteria for the detection of pneumonia in adults: Guidelines for ordering CXR in the emergency dept. J Emerg Med. 1989).
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Chest X‐ray
• Standard view is Posterior‐anterior (PA) view and
• LEFT lateral view
• Anterior‐posterior (AP) view used if pt too sick to stand
– Heart is further away (distorted)
Systematic Approach
Generally least to most interesting
1.Adequacy of the film
2.Upper abdomen
3.Thoracic cage (soft tissue and bones)
4.Mediastinal structures
5.Lungs
a. each individually
b. comparison of both
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X‐ray Quality
1. Penetration – thoracic spine is just visible
2. Alignment – clavicles should be equal
3. Nothing is cut off – entire chest visualized
4. Sufficient Inspiration – 9 or 10 ribs seen
Upper abdomen
1. Right hemi‐diaphragm slightly elevated
2. Gastric bubble
3. No free sub‐diaphragmatic air
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Subdiaphramatic air
Thoracic Cage
• Scapula
• Humerus
• Shoulder joint
• Clavicle
• Ribs
• Sternum
• Thoracic spine
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Mediastinal Structures
• Mediastinum & heart
– Trachea (including carina)
– Mediastinal widening (> 8cm = pathology)
– Cardiac borders
– Cardiothoracic ratio
(> ½ the width of the thorax = cardiomegaly)
• Hila
Left ventricle
Aortic knob
Right atrium
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Cardiothoracic ratio
Lungs
• Right lung lobes
– Upper
– Middle
– Lower
• Left lung
– Upper
– Lingula (lower portion of upper lobe)
– Lower
Lungs
• Lung markings well defined
• Compare for symmetry
• Various shades of Opacities – Alveolar or interstitial process