Final Exam Material

Question 1

Inventor of CT Scan 1972

Answer 1

Godfried Hounsfield

Question 2

Conventional CT (default)

Answer 2

Tube rotates 360 degrees then table moves

Question 3

Helical CT

Answer 3

Moves in a continuous figure 8 while patient slides through

Question 4

aka’s for helical CT

Answer 4

Spherical or multidetector

Question 5

Hounsfield Units (HU)

Answer 5

Calcium +1000
Water 0
Air -1000

Question 6

Maximizing bone vs soft tissue vs lung parenchyma/ Windowing

Answer 6

2000 HU of density captured per image: human eye see only 400 HU at a time

Question 7

Best modality for fine bone detail

Answer 7

CT Scan

Question 8

Best modality to see calcium

Answer 8

CT Scan

Question 9

Modality to find OPLL

Answer 9

CT Scan

Question 10

Modality to find subtle fractures

Answer 10

CT Scan

Question 11

Thin section CT

Answer 11

aka high resolution CT

Question 12

Thin section/ high resolution CT

Answer 12

Gold standard for chest imaging

Question 13

Bone Window

Answer 13

Allows you to ddx cortex from medulla

Question 14

Soft Tissue Window

Answer 14

Cortex and Medulla blend together. Muscular structures can by seen

Question 15

Helical CT advantages

Answer 15

Image large areas in detail in short period of time. Higher dose and higher cost. Good for screening trauma in unconscious patients

Question 16

CT advantages

Answer 16

Great for bone detail, fracture and tumor assessment, calcium lesions, GI/GU conditions, acute brain bleeds

Question 17

3D CT

Answer 17

Used for reconstructive surgery and visceral conditions

Question 18

Jefferson Fx

Answer 18

Often not visible on plain film, occurs via axial load to vertex of head, rust sign. CT is definitive

Question 19

Dens Fx

Answer 19

Minimal displacement on plain film. Dens NOT well visualized on MR. CT is definitive

Question 20

Hangman’s Fx

Answer 20

Very hard to see on plain film, via forced hyperextension injury, CT definitive

Question 21

UID/BID

Answer 21

Very hard to see on plain film (bow tie sign/inverted bun sign), via hitting head and shoulder simultaneously or head turned during flex/ext injury, CT definitive

Question 22

OPLL

Answer 22

Confirmed with CT but MR better to see degree of neural compromise. Manual adjusting contraindicated

Question 23

Tumors

Answer 23

CT to view margins of lesion and tumors that have calcium

Question 24

Lung Lesions

Answer 24

CT is gold standard for almost all lung lesions

Question 25

CT and GI/GU

Answer 25

CT excellent resolution. Ultrasound may be a better alternative

Question 26

Acute brain bleed

Answer 26

CT great to assess stroke, epidural or subdural bleeds

Question 27

Metastatic disease (nuclear medicine)

Answer 27

Can image entire body with one exam (same exposure as C/T/L/P x-ray series); sensitive to early change

Question 28

Fatigue fracture (nuclear medicine)

Answer 28

Sensitive but doesn't explain problem if scan is negative; MR is better choice

Question 29

Paget's (nuclear medicine)

Answer 29

Great to identify which bones are involved

Question 30

ddx bone island vs early mets (nuclear medicine)

Answer 30

For a px over 40 with pain and no series of previous films available. If scan is cold it's a bone island

Question 31

Bone scan/scintigraphy (nuclear medicine)

Answer 31

Fracture will stay hot for 12-18 months. Tc-99 most common.

Question 32

Nuclear medicine

Answer 32

Aka bone scan/scintigraphy. Sensitive but not specific. Hot benign processes: Paget's and FD. Cold for MM

Question 33

Nuclear medicine technique

Answer 33

A radionucleide is tagged to a metabolite and areas of increased uptake visualized.

Question 34

Single Photon Emission Computed Tomography (SPECT)

Answer 34

Slices through a bone scan. Good to ddx active from inactive pars defect

Question 35

Active pars defect (SPECT vs MRI)

Answer 35

Non union of stress fracture in pars due to repetitive hyperextension. Eventually fibrous bridge might form (not visible on X-ray)

Question 36

Active = fractured pars defect

Answer 36

Boston hard brace holds body in slight flexion so healing can occur

Question 37

Px with DISH getting numb. You suspect OPLL

Answer 37

Confirm OPLL with CT

Question 38

Px with OPLL and neurological signs

Answer 38

Get MRI to see degree of cord impingement

Question 39

CT abdomen imaging

Answer 39

Use oral contrast

Question 40

CT imaging with kidneys involved

Answer 40

Use IV contrast

Question 41

Reformatting

Answer 41

Volume averaging used to create slices in any plane

Question 42

HU; X-ray vs CT

Answer 42

X-ray HU = heat unit | CT HU = Houndsfeild

Question 43

Positron Emission Tomography (PET)

Answer 43

Tag radionucleotide with sugar to mimic sugar uptake. Can be used with CT or MRI. Good for tumor evaluation and screening for recurrence

Question 44

PET advantage

Answer 44

Assessing many tissues at once

Question 45

PET disadvantage

Answer 45

Expensive and technically challenging