Imaging

Question 1

What is unique of Xray techniques?

Answer 1

Uses photons from tungsten target to recording plate

The dark areas represent air/emptyness

The whiter the area, the thicker/more dense the area is

Question 2

What dyes can be used with negative xrays for better imaging?

Answer 2

Barium sulfate and Iodine compounds

Question 3

What should be positioned closer to the recording plate for a normal, not enlarged view?

Answer 3

If wanting to view the heart, patient should be laying anteriorly on the recording plate (PA view). If the patient was laying in an AP view, the heart would look enlarged

Question 4

Fluoroscopy?

Answer 4

Rotation of the xray source and equipment on the C arm to provide a 3D view of the body region

Question 5

What is unique of CT (computed tomography) techniques?

Answer 5

They are helical xrays reconstructed into axial sections, which are then stacked and viewed 3D.

can be used with barium/iodine

usually looked at inferior to superior

Question 6

What are the units on the hounsfield scale for water, air, compact bone, and soft tissues?

Answer 6

Water: 0
Air: -1000
Compact Bone: +3095
Soft Tissue: -100 to +100

Question 7

What is the window width and what would the numbers above and below be displayed as?

Answer 7

range of greyscale mapped onto hounsfield scale, above numbers in window width are white, and below window width are black, window width is middle grey

Question 8

What is unique to MRI techniques?

Answer 8

1. powerful static magnetic field aligns hydrogen atoms nuclear spins
2. Pulsed radio waves knock spins out of alignment
3. receiver coils measure energy released during nuclear spin realignment

Can use T1 or T2

Question 9

What does T1 stand for and what will cerebrospinal fluid look like?

Answer 9

Longitudinal relaxation time. CFS/fluid is dark in T1

Question 10

What does T2 stand for and what will CSF look like?

Answer 10

Transverse relaxation time. CSF/fluids are light in T2