Week 6 - CXR & CT

Question 1

Order from radiopaque to radiolucent: muscle, bone, metal, air, fat.

Answer 1

Metal, bone, muscle, fat, air.

Question 2

Standard xray has x-ray tube how far away from plate and subject?

Answer 2

6 feet, PA

Question 3

Notable differences in AP x-ray vs PA

Answer 3

Heart appears enlarged (more time for beam to diverge). PA generally better quality

Question 4

How to ensure patient isn’t rotated in x-ray

Answer 4

Trachea midline, clavicles equidistant from midline, both costophrenic angles visible.

Question 5

ABCDEF of CXR interpretation

Answer 5

Airway and adenopathy (usually mediastinal), bones and breast shadows, cardiac silhouette, diaphragm, everything around the lung fields (scan for free air, soft tissue masses/lymph nodes), fields (lung fields).

Question 6

Things to look for on a lateral CXR

Answer 6

Vertebrae go from more radiopaque to more radiolucent from superior to inferior. There should be an anterior clear space in front of the heart.

Question 7

When is contrast used with chest CTs?

Answer 7

Evaluate vasculature

Question 8

Considerations for CT as compared to CXR

Answer 8

Cost: $100 vs $1500, radiation: 10 vs 580 milli rem. Consider renal function when using contrast dye.

Question 9

How does a PE appear on CT?

Answer 9

Vasculature is white because of dye. Area of embolus/filling defect is more radiolucent.