Clinical imaging of thorax part I (AS lecture)

Question 1

Wilhelm Roentgen

When were X-rays discovered and by who

Answer 1

• 1895
• wilhelm conrad roentgen

Question 2

what appears black on x ray

Answer 2

air

Question 3

what appears gray but darker than soft tissue on x ray?

Answer 3

fat

Question 4

what 2 things appear white-ish gray and have the same density on radiographs?

Answer 4

• fluid
• soft tissue

Question 5

what is the most dense naturalling occuring material in the body that absorbs more x-rays in the body and where is most of it found?

Answer 5

• calcium
• mostly found in the bones

Question 6

what material usually absorbs all x-rays and appears the whitest on conventional radiographs?

Answer 6

metal

Question 7

what are 5 advantages of plain radiographs

Answer 7

• quick
• cheap
• low dose radiation
• can be portable
• can detect range of pathologies

Question 8

X-ray techniques

what are 4 disadvantages of plain radiographs

Answer 8

• lacks detail
• ionising radiation (even though low amounts)
• limited range on densities
• difficult to perform on some patients

Question 9

X-ray projections

outline 2 reasons why PA view is preferred over AP view in X ray imaging

Answer 9

PA views are:
- higher quality
- heart size is nearer to real size as heart is nearer to the detecter

Question 10

outline 4 x-ray projection techniques

Answer 10

• posterior anterior/anterior posterior view
• left lateral/right lateral
• AP recumbant ( AKA AP supine)
• right oblique/left oblique view

Question 11

why is heart magnification minimised in PA view vs AP view?

Answer 11

heart magnification is minimised due to the use of a narrower beam, produced by the increased distance between the source and the patient.

Question 12

what 2 reasons explain why heart size is exaggerated in AP view compared to PA view?

Answer 12

heart size is exaggerated in AP view because:
- heart is farther away from detector
- X-ray beam is more divergent as source is nearer the patient

Question 13

what are the 4 main things to observe when conducting an X-ray?

Answer 13

• Rotation
• inspiration/expiration
• penetration
• heart (cardiac shadow)

Question 14

what 3 questions are asked when checking for rotation in an X-ray?

Answer 14

3 questions asked when checking for rotation in X-rays are:

• do the thoracic vertebral spines align in the centre of the sternum and between the clavicles?
• are the clavicles in the same level
• is the trachea in the midline?

Question 16

how many anterior and posterior parts of the ribs should be visible in full inspiratory chest radiograph films?

Answer 16

posterior: 9-10

anterior:5-7

Question 17

where do the anterior parts of the ribs intersect the diaphragm?

Answer 17

• intersect the diaphragm at the mid-clavicular line

Question 18

what increases in likelihood if a chest X-ray is underexposed and why does this increase in likelihood?

Answer 18

This increases the likelihood of missing an abnormality in overlying structures as the thoracic vertebrae will not clearly be visible

Question 19

what is a characteristic of over-penetrated chest x-rays, what does this decrease/make absent on x-ray and what 3 things can be missed on an x-ray because of this?

Answer 19

characteristic:
- diffusely dark

this decreases the visibility of pulmonary markings or makes them absent on chest x-ray

3 things that can be missed on an x-ray because of this are:
- pneumothorax
- consolidation
- emphysema

Question 20

state what ABCDE is in other things to observe in X-ray radiographs

Answer 20

A: Airways Trachea, endotracheal tube, etc.

B: Bones (Clavicles, ribs, sternum, thoracic vertebrae, etc.)
Cardiac shadow
Diaphragm: Remember the right hemidiaphragm is slightly higher.
Everything else: Any wire, tubes, pacemaker, effusions, etc.

Question 21

what level is the aortic knuckle visualised on chest x-ray?

Answer 21

• around the level of T4/T5 or lateral to the carina

Question 22

what is the characteristic of the costophrenic and costo-cardiac angles?

Answer 22

characteristic:
- should be sharp and well-defined

Question 23

what does it mean if the costo-cardiac and costophrenic angles are blunted/lost?

Answer 23

this means there is a chance fluids in the pleural cavity (known as pleural effusion)

Question 24

where is the gastric bubble normally seen?

Answer 24

under the left hemidiaphragm

Question 25

what does free air under the right hemidiaphragm suggest?

Answer 25

suggests bowel perforation

Question 26

what does deviation of the trachea from the midline suggest?

Answer 26

suggests presence of a **mediastinal mass **or tension pneumothorax