Lecture 7: Introduction to Anatomical Imaging Flashcards Preview

04. MSK Exam 2 Final > Lecture 7: Introduction to Anatomical Imaging > Flashcards

Flashcards in Lecture 7: Introduction to Anatomical Imaging Deck (23)
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1

What color would the contrast agent be in a normal X-Ray with contrast?

 

What color would it be in a negative image / subtraction technology?

White

 

Black

2

In an x-ray, what colors will the bone and air filled organs be?

Bone: White

Organs with air: Dark

3

What is the correct orientation for a cardiac (thorax) Xray?

Why?

PA (Posterior to Anterior)

Because AP makes the heart look enlarged, since it is closer to the tungsten target

 

Basically keep the structure of interest closer to the recording plate!  

4

How many frames per second would you use for fluoroscopy of the peripheral vasculature?

 

What about for coronary artery studies?

Two to Three FPS

 

15 to 30 FPS

5

What is digital subtraction angiography?

A fluoroscopy method by which an image is taken, contrast is introduced, and then another image is taken and compared with the first. Everything that doesn't show the contrast is removed from the display for better imaging. 

6

What is the downside of digital subtraction angiography?

You have to inject the contrast directly into an artery, which can cause a pulsatory bleed

7

What is computed tomography?

Helical Xrays are reconstructed into an axial (transverse) view of a body section

8

Which direction are you looking when reading a CT?

From the feet up

9

What is the correct Hounsfield Scale window level and width for

Lung Tissue

Level: -550

Width: 1600

Remember that air is -1000, so it makes sense that lung is really low, and since we're starting so low, we need a wide window.

10

What is the correct Hounsfield Scale window level and width for

Soft Tissue

Level: 70

Width: 450

11

What is the correct Hounsfield Scale window level and width for

Bone

Level: 500 ish

Width: 1000-3000 ish

Really high and really wide, since bone varies greatly in density, and is obviously very dense.

12

What is cheaper, CT or MRI?

CT

13

What must you do before you order a CT with contrast?

Check renal function!

14

Would you have to have your patient hold still more for an MRI or a CT?

MRI

CT's are more resistant to motion

15

Which image can be manipulated post hoc; MRI or CT?

CT

MRI has to be set beforehand, CT has adjustable grey scale using the Hounsfield scale

16

Is fluid light or dark in T1 MRI?

Dark

17

Is fluid light or dark in T2 MRI?

Light

18

Which has better soft tissue contrast, MRI or CT?

MRI

19

Which is worse for claustrophobic patients, MRI or CT?

MRI

20

Why shouldn't metal workers get an MRI?

They can have metal shards in their tissues (eg the eye) and not know it. The MRI magnet can pull it out.

21

What can Nuclear Medicine imaging be used for?

Finding areas of metabolic "hotspots," especially metastases of cancers.

22

For Ultrasound, when would you use a 7-15 MHz transducer?

When you are trying to visualize structures near the surface

(thyroid gland, neck vessels, breasts, testes)

23

For Ultrasound, when would you use low frequency (1 to 3.5 MHz) transducers?

To visualize deep structures