Spine & Extremities

Question 1

What are the names of the soft center and firm outer layer of a vertebral disc?

Answer 1

soft center: nucleus pulposus

firm outer layer: anulus fibrosus

Question 2

At what vertebral level does the spinal cord end?

Answer 2

T12-L1.

Question 3

After the spinal cord ends, what does it taper into?

Answer 3

conus medullaris

Question 4

What is the nerve bundle that extends inferiorly from the spinal cord?

Answer 4

cauda equina

Question 5

What are the two common sites for spinal fracture?

Answer 5

C6-C7 & T12-L2

Question 6

What is a sequestered disc? What else is this called?

Answer 6

a portion of a disc’s nucleus completely breaks free and migrates from its normal position; herniated disc

Question 7

Define spondylosis.

Answer 7

hypertrophy of the facet joints. CAN lead to spinal stenosis

Question 8

Define spondylolysis.

Answer 8

a defect of the pars interarticularis caused by an osteophyte

Question 9

Define spondylolisthesis.

Answer 9

anterior “slipping” of a vertebral body over an inferior one. caused by degenerative changes in the facet joints.

Question 10

What is the recommended slice thickness for the c-, t-, and l-spine?

Answer 10

c-spine: 1-2 mm

t- and l-spine: 3-5 mm

Question 11

What are the SFOV and DFOV for the spine?

Answer 11

SFOV: large, 48-50 cm
DFOV: small, 10-15 cm

Question 12

What window levels and widths are used for CT of the spine?

Answer 12

bone: WL 300 & WW 2000

soft tissue: WL 50 & WW 400

Question 13

When would IV contrast be indicated for CT of the spine? How much and at what flowrate?

Answer 13

metastatic disease, soft tissue mass, infection, and abscess. 100-125 mL at 2-3 mL/sec during the portal venous phase.

Question 14

What is the most common malignancy of the skeletal system?

Answer 14

Multiple Myeloma; systemic malignancy of the plasma cells of the bone marrow

Question 15

What is the infection of a bone?

Answer 15

Osteomyelitis

Question 16

_____-section slices are acquired with at least ___% overlap for muscoskeletal scans.

Answer 16

thin-sections (<1.25 mm); 50% slice overlap

Question 17

What is the ideal position for scans of the upper extremity?

Answer 17

prone, with affected limb extended over head. hand pronated for hand, wrist, forearm. hand supinated for elbow scans (until humeral epicondyles are parallel with the scan table)

Question 18

Describe the axial imaging plane for a foot.

Answer 18

leg fully extended with foot flexed and toes pointing up. parallel to the foot’s plantar surface.

Question 19

Describe the oblique axial imaging plane for a foot.

Answer 19

axial plane parallel to the metatarsals, roughly 20-30 degrees caudal from the direct axial plane. used to assess the tarsal-metatarsal joints

Question 20

What is best demonstrated by the sagittal plane of the foot?

Answer 20

tarsal and metatarsal bones and joints

Question 21

Describe the oblique coronal imaging plane for a foot.

Answer 21

scan plane is perpendicular to the long axis of the metatarsals. best shows ankle joint

Question 22

What is the best plane to image the ankle and hindfoot?

Answer 22

direct coronal, perpendicular to the tibia

Question 23

What is tarsal coalition?

Answer 23

it is the abnormal union of adjacent bones of the ankle. it is the most common in the talocalcaneal and calcaneonavicular joints

Question 24

What type of lower leg fracture is best demonstrated by CT over x-ray?

Answer 24

tibial plateau fx

Question 25

How does inflammed muscle appear compared to non-inflammed with contrast enhancement?

Answer 25

inflammatory muscle appears less enhanced by contrast than normal muscle tissue

Question 26

What anatomy is included on a CT of the shoulder?

Answer 26

glenohumeral joint: from the entire humeral head through the proximal humerus

Question 27

What is the best way to limit the out-of-field artifacts caused by the body during a CT of the shoulder?

Answer 27

center the shoulder at the midtable, use a large SFOV, and use a smaller DFOV. streaking will still occur but will be limited to the periphery of the image

Question 28

Which structures make up the acetabulum?

Answer 28

ischium, ilium, and pubis

Question 29

Name two indications for an IV contrasted study of the pelvis.

Answer 29

pelvic vasculature and bladder