Medical Imaging: Normal Chest Anatomy

Question 1

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What are the five radiographic densities?

Answer 1

• Air
• Fat
• Bone
• Metal
• Fluid (soft tissue)

Question 2

What is the standard x-ray view? Full inspiration or full expiration? Why is the patients close to the film?

Answer 2

• Posteroanterior view
• Full inspiration
• Standing close to film reduces magnification and increases sharpness

Question 3

What are some limitations of a lateral CXR?

Answer 3

• Left hemidiaphragm is not differentiated from the heart anteriorly; same density
• Right sided nodule will appear larger than an identical left sided nodule due to increased magnification

Question 4

What are some drawbacks of an AP film?

Answer 4

• Increased magnification
• Decreased sharpness

Question 5

When might an AP film be used for a CXR?

Answer 5

For children, or adults who are too sick to stand

Question 6

Why is a lordotic x-ray used?

Answer 6

To get clavicles off apices of lungs

Question 7

What can a lateral decubitus view help to identify?

Answer 7

Air or fluid trapped in lungs

Question 8

What can an expiratory view be used to identify?

Answer 8

• Pneumothorax (air going into pleural space)
• Focal air trapping; lung won’t collapse like normal

Question 9

How do Hounsfield units work?

Answer 9

Reflection of how well a material attenuates x rays relative to water (water = 0)

Question 10

Indications for standard CT chest

Answer 10

• Pneumonia
• Malignancy
• Pleural Disease

Question 11

Inidcations for high-res CT

Answer 11

Parenchymal disease (e.g. interstitial lung disease)

Question 12

Indications for CT Aortogram

Answer 12

Aortic pathology

Question 13

Indications for CT Pulmonary Angiogram

Answer 13

Pulmonary embolism

Question 14

Indications for CT Coronary Angiogram

Answer 14

Coronary artery disease