Etc. MSK Exam 1

Question 1

AP/PA view of CXR

Answer 1

IN CXR, PA is preferred due to the enlargement of heart and mediastinum in a AP view. If you want normal size of image, put it closest to target.

Question 2

Fluoroscopy

Answer 2

Real time X-ray. Used to GI studies, angiographic studies, cateters, and ortho surgery.

Question 3

Digital subtraction angiography

Answer 3

Similar to fluoroscopy, but other tissues are subtracted so you only see the artery.
Used in sent placement, catheter placement.
More invasive as artery must be entered to gain access to vasculature.

Question 4

Hounsfield scale

Answer 4

Measures density. Water is 0 and compact bone is 3095. Most soft tissues between -100 and 100.

Question 5

Window level and width

Answer 5

256 levels of gray. The level is the middle gray and a the width is the range. Below the window is black and above are white. Wide window is good for bone, narrow is good for soft tissues.

Question 6

Pros and cons of CT

Answer 6

Pros: quick, motion not a big problem, gray scale can be manipulated, resolution excellent, available and cheap.
Cons: Los of radiation. If using contrast, must check kidneys, some pts allergic to iodine.

Question 7

T1 vs T2 Weighted MR

Answer 7

T1: longitudinal. Time for spinning protons to realign with external mag field. Fluid is dark.
T2: transverse. Measure amt of time for spinnign protons to align perpendicular. Fluid is light in T2.

Question 8

MCN roots

Answer 8

C5-C7

Question 9

Median N roots

Answer 9

C6-T1

Question 10

Ulnar N roots

Answer 10

C8-T1

Question 11

Radial N roots

Answer 11

C5-T1