Imaging

Question 1

List the descending order of attenuation value.

Answer 1

Metal, bone, water, muscle, fat, air.

Question 2

Where is the x-ray detector placed in a PA radiograph?

Answer 2

On the patient’s chest.

Question 3

Where is the x-ray detector placed in an AP radiograph?

Answer 3

On the patient’s back.

Question 4

Which are preferred, AP or PA, and why?

Answer 4

PA, because the shorter distance between the detector and the organ results in a more accurate depiction of the anatomy, whereas an AP may magnify certain organs.

Question 5

Should x-rays be taken at full expiration or full inspiration?

Answer 5

Full inspiration.

Question 6

How many posterior and anterior ribs should be visible?

Answer 6

10 posterior ribs, 6 anterior ribs.

Question 7

What is very important when it comes to reading chest x-rays?

Answer 7

Having a systematic approach when looking at an x-ray.

Question 8

What is a silhoutte sign?

Answer 8

The loss of normal borders between two structures on a radiograph, when they are very similar in density.

Question 9

Approximately where is the I-line? What does it separate?

Answer 9

It goes right through the carina/sternal angle (T4), between ribs 4 and 5. Anything above it is upper lobe, any thing below is lower lobe.

Question 10

Which lung has a middle lobe? Between which ribs is it located?

Answer 10

The right lung. Ribs 4 and 6.

Question 11

What ribs to the minor fissure and the major/oblique fissure run along side?

Answer 11

Minor fissure: rib 4, oblique fissure: rib 6

Question 12

What does the minor fissure separate? major/oblique fissure?

Answer 12

The minor fissure separates the upper and middle lobes in the right lung. The oblique fissure distinguishes the inferior lobe in both lungs.

Question 13

What are the boundaries of the anterior, middle and posterior mediastinum?

Answer 13

Anterior: posterior surface of sternum to anterior surface of pericardium, aorta and brachiocephalic veins.
Posterior: posterior surface of pericardium and great vessels to anterior surface of spine.
Middle: between anterior and posterior. Contains the heart and great vessels.

Question 14

Where is the line that distinguishes the superior and inferior mediastinum drawn?

Answer 14

At T4, through the sternal angle.

Question 15

Where can the superior vena cava be found?

Answer 15

To the right of where the trachea bifurcates. This is only visible when there is pathology.

Question 16

Which hemidiaphragm should be slightly higher than the other.

Answer 16

The right should be higher than the left, due to the liver.

Question 17

True or false: the heart should not exceed 50% the width of the thorax.

Answer 17

True.

Question 18

If the patient is standing upright, where in the lungs will the pulmonary vasculature be more prominent?

Answer 18

In the lower lobes, due to the effect of gravity on the circulating blood.

Question 19

On lateral films, why is the thoracic spine easier to visualize as you go from top to bottom of the lungs?

Answer 19

There is more soft tissue in the apices and more air in the bases.

Question 20

What causes pulmonary edema?

Answer 20

Increased hydrostatic pressure of lung capillaries or increased capillary permeability Fluid can accumulate in the interstitium or alveoli.

Question 21

What is an early sign of pulmonary edema?

Answer 21

Kerley B lines. They indicate interstitial edema.

Question 22

What pattern does alveolar edema have in the lungs?

Answer 22

A butterfly pattern, with puffy white areas, characterized by a central predominance of shadows with a clear zone at periphery lobes.

Question 23

What is the most common non-cardiogenic type of pulmonary edema?

Answer 23

Neurogenic. It is caused by sympathetic vasoconstriction, leading to an increase in pulmonary venous pressure and a shift of blood from systemic to pulmonary circulation, increasing pulmonary capillary pressure and permeability.

Question 24

What can go wrong in the pleural capillaries that leads to pleural effusion?

Answer 24

Too much hydrostatic pressure on the arterial side or too little osmotic pressure on the venous side.

Question 25

Can an x-ray by itself diagnose pneumonia?

Answer 25

No, but you can get an idea that there’s something wrong.

Question 26

What is unique about the presentation of pneumonia on an x-ray?

Answer 26

The particulate matter (not fluid) consolidates in a single portion of the lung.