MSK Scanning

Question 1

T/F
Skeletal trauma can generally be studied by standard radiographs

Answer 1

Trye

Question 2

T/F
In complex anatomic regions (pelvis, shoulder, foot, ankle) more precise information about the presence, location, orientation and relationship of fracture fragments can be obtained with a CT scan

Answer 2

True

Question 3

What can be extremely useful for skeletal trauma imaging on CT?

Answer 3

Multiplanar reformations and 3D reconstructions

Question 4

What is a useful method of evaluating bone and soft tissue tumors?

Answer 4

General MSK scanning

Question 5

T/F
General MSK scanning adds details to information already obtained with radiographs

Answer 5

True
Ex. Complex fractures

Question 6

T/F
MSK scanning can also evaluate joints, with the introduction of air or iodinated contrast

Answer 6

True

Question 7

When is contrast used for scanning the MSK?

Answer 7

Tumors, infection, joints
-osteosarcoma
-osteomyelitis
-osteochondroma

Question 8

What are some advantages of MSK scanning?

Answer 8

1. Cross sectional anatomy and spatial relationship
2. Ability to image both sides to permit comparison
3. Ability to image bone and soft tissue simultaneously
4. Enhanced contrast sensitivity
5. MPR and 3D reformats
6. Can be combined with contrast introduction to address other diagnostic information

Question 9

-acquisition of slices as thin as 0.5mm (increased spatial resolution)
-allows for MPR in any plane with the same spatial resolution as the original sections
-allows for extensive anatomic coverage

Answer 9

MDCT

Question 10

-patient supine
-head first
-AP and lat scouts

Answer 10

Upper extremity
*hand/wrist not done supine

Question 11

T/F
Although upper extremities are done with the patient lying supine, hand and wrist scans are not done supine

Answer 11

True

Question 12

-patient supine
-feet first
-AP and lat scout

Answer 12

Lower extremities

Question 13

T/F
Techniques are tailored to each patients region separately

The plane of the CT section should be perpendicular to the long axis

Answer 13

True

Question 14

T/F
MSK requires multiplanar reformatting (MPR)

Answer 14

True

Question 15

T/F
3D is usually required for fractures demonstrated on CT and also aids in surgical planning

Answer 15

True

Question 16

What is used to aid with patient positioning to hold area of interest steady?

Answer 16

Pillows and angle sponges

Question 17

T/F
Breath holds are not necessary in general MSK scanning

Answer 17

True

Question 18

T/F
Ankle is scanned with a straight leg, and the opposite leg bent at the knee

Answer 18

True
*if leg is bent and foot is flat on the table, the gantry would need to be angled

Question 19

T/F
IV contrast is not routinely required for general MSK scanning

Answer 19

True

Question 20

What is CT MSK used to evaluate?

Answer 20

-bone
-tumors
-multiple and complex fractures
-joints (arthrograms)

Question 21

-both sides should be symmetrical
-lower extremity: supine feet first
-upper extremity: head first, supine or prone
-scouts: AP/LAT
-ACQUISITION: 0.625mm x 0.625mm
-MPR: all plane, including oblique planes at 1 mm x 1 mm
-contrast: not routinely used
-respiratory phase: none

Answer 21

CT MSK general protocols

Question 22

When would contrast be used for MSK general protocol?

Answer 22

To assess vascularity of tumors, or vascular injuries (ex. Runoffs)

Question 23

Why would a respiratory phase be used for MSK general?

Answer 23

If breathing will be detrimental to the image

Question 24

T/F
CT sections should be perpendicular to the long axis of the bone

Answer 24

True

Question 25

Visualization of vessel in upper extremity

Answer 25

Upper runoff

Question 26

Visualization of vessels in lower extremity

Answer 26

Lower runoff

Question 27

T/F For a runoff protocol, contrast should always be injected in the unaffected extremity

Answer 27

True *for any contrast injection

Question 28

T/F When arm is positioned above the head, right or left can be confusing

Answer 28

True *radiopaque marker used to determine L and R and scan orientation

Question 29

Indication: Complex fractures demonstrated of the radius or ulna, carpal bones OR subtle fractures not visualized on radiographs

Answer 29

CT wrist

Question 30

How is the patient positioned for a CT wrist?

Answer 30

Arm extended over head: prone or supine *if arm can not be extended, arm is rested on abdomen as a last resort ****mA must be increased to reduce noise levels****

Question 31

T/F Acquisition of the foot and ankle can be obtained in a number of different imaging planes

Answer 31

True *depends on the aspect of primary concern

Question 32

How are patients most often positioned for foot/ankle imaging?

Answer 32

Supine with legs flat on the table *taping feet together or using a foot holder will help prevent motion during the scan

Question 33

T/F Both ankles can be scanned with a 22cm DFOV allowing side by side comparison of the symptomatic ankle with the normal ankle

Answer 33

True

Question 34

What should the DFOV include for the ankle?

Answer 34

Large enough to include hind foot, mid foot, proximal bases of all MTs

Question 35

What should the DFOV include for foot?

Answer 35

Large enough to include the entire forefoot (MTs and phalanges) along with the hind foot and mid foot

Question 36

The plane parallel to the plantar surface of the foot

Answer 36

Axial plane

Question 37

How is the axial plane acquired for foot?

Answer 37

Acquired directly when the patient is positioned with toes pointing straight up

Question 38

Patient positioned with bent knees so that the feet lie flat on the table

Answer 38

Oblique coronal plane

Question 39

How is the oblique coronal plane acquired for feet?

Answer 39

Gantry tilted 20-30 degrees (top of gantry away from the patient) Scan plane is perpendicular to the subtalar joint