CT

Question 1

What are disadvantages of conventional radiography?

Answer 1

no depth detail
organs/structures superimposed

Question 2

What is cross sectional imaging?

Answer 2

Slices of human body in transverse/axial plane

Question 3

CAT scans stand for?

Answer 3

Computed axial tomography

Question 4

What are 3 planes of body?

Answer 4

Axial
Coronal
Sagittal

Question 4

What is CT?

Answer 4

Using computer technology with x-ray to image body cross-sectionally

Question 5

What type of image receptor is used in CT?

Answer 5

defector

Question 6

What is the width of the slice determined by?

Answer 6

Width of x-ray beam

Question 7

What is the image represented by?

Answer 7

MATRIX of numbers

Question 8

What does each pixel have?

Answer 8

number that represents the x-ray attenuation in corresponding voxel of object
Each pixel has a location

Question 9

What is a high CT number equal?

Answer 9

white areas because of increased attenuation

Question 10

What does a low CT number equal?

Answer 10

Black because of decreased attenuation

Question 11

What is the Hounsfield scale?

Answer 11

water is 0
air is -1,000
bone is 1,000

Question 12

What does a narrow window allow?

Answer 12

Enhancing contrast of tissue
eg soft tissue window, bone window

Question 13

How does CT work (3 steps)?

Answer 13

x-ray tube linked to detector
tube and detector circle patient
takes hundres of x-ray pictures

Question 14

What are 4 advantages of CT?

Answer 14

Visualization of internal organs
avoids superimposition of tissues
high contrast allows differentiation of organs
viewed in multiple planes

Question 15

what was the intial scanner?

Answer 15

Shoot and step (1 slice)
table only moves when source is off

Question 16

What are spiral scanners?

Answer 16

Constant table movement

Question 17

What is multislice scanners?

Answer 17

Multiple detector rings

Question 18

What is the current rotation spped?

Answer 18

4 per second

Question 19

What are 3 resolutions?

Answer 19

Spatial
Contrast
Tempora

Question 20

What are 3 pieces of equipment in CT?

Answer 20

Gantry (doughnut on side)
computer
table

Question 21

What is the procedure?

Answer 21

Patient lies in supine table & arms placed over head (body scans)
table moves in and out of gantry
holds breath at various times
IV contrast injected
oral contrast administered

Question 22

What is the topogram?

Answer 22

Plain 2D image as initial scout view
used to define start & end of main scan
Find any artefacts

Question 23

What is windowing?

Answer 23

changing brightness & contrast image
focuses on different anatomical structures

Question 24

What does MRS allow for?

Answer 24

Selection of optimal plane to image an organ/disease process

Question 25

What are 2 limits in CT scans?

Answer 25

aperture size patient limits

Question 26

what is the axial plane?

Answer 26

looking from patients feet up left side of image is patients right side

Question 27

what does orla constrats media do?

Answer 27

delineate small bowel

Question 28

What are 2 types of oral contrast?

Answer 28

gastrogafin & barium

Question 29

What does IV contrast allow for?

Answer 29

demonstrate blood vessels improves sensitivity of lesions small possibility of reactions

Question 30

What are 6 medial applications in CT?

Answer 30

Oncology - staging & diagnosis stroke trauma - bone damage guiding biopsy procedures screening for disease bone mineral densitometry

Question 31

What are the top 4 cancer types?

Answer 31

lung colorectal breast prostrate

Question 32

What are 4 disadvantage of brain imaging?

Answer 32

unable to visualize vasculature without contrast media poor visualization of cerebellum poor sensitivity acute stroke no anatomical detail

Question 33

What does CT images show in the brain?

Answer 33

Exact, number, location and affect of tumor on adjacent structures

Question 34

What type of strokes do CT distinguish?

Answer 34

Hemorrhagic or ischemic

Question 35

What does CT perfusion imaging measure?

Answer 35

cerebral blood flow for early stroke detection

Question 36

What 4 things can CT tell us about hemorrhage?

Answer 36

identification, location, classification and age of hemorrhage

Question 37

How can CT demonstrate fractures?

Answer 37

due to high spatial resolution imaging

Question 38

What 4 things can CT tell us about sinuses?

Answer 38

Which sinuses are affected presence of polyps anatomical variants anatomy of OMU prior to FESS Sx

Question 39

What can CT scans visualise in the inner ear?

Answer 39

ossicles and semicircular canaks bone erosions

Question 40

What 4 diseases do CT investigates?

Answer 40

hearing loss tinnitus pain swelling

Question 41

What is high resolution CT good for?

Answer 41

Chronic interstitial lung processes eg emphysema and fibrosis airspace diseases

Question 42

What 3 things can CT detect?

Answer 42

pulmonary angiography pE detection abdominal aortic aneurysm detection

Question 43

What is used to image the hear?

Answer 43

Modern multislice CT scanners

Question 44

How is CT used in oncology?

Answer 44

Disease detection staging monitoring

Question 45

What does CT scans show about tumour follow up?

Answer 45

patients response to treatment disease progress

Question 46

What can CT scans be used for abodomn?

Answer 46

acute abdomen solid organ injury oncology appendicitis/renal stones

Question 47

What sex is pelvis CT limited to?

Answer 47

Females

Question 48

What can pelvis scans show?

Answer 48

Oncology scanning & staging fracture detection

Question 49

What is a CT colongraphy?

Answer 49

Scan if large bowel air pumped into colon

Question 50

What are 3 examples of CT intervention?

Answer 50

Biopsies Drainage Tumour ablations

Question 51

What is the CT dose?

Answer 51

2-20mSv 1 in 2000 risk of additional cancer incidence

Question 52

What does increasing dose allow for?

Answer 52

Better image quality

Question 53

what is the effective dose in chest CT?

Answer 53

~8 mSv

Question 54

What is a ceretom scanner?

Answer 54

8 slices brain CT in trauma units

Question 55

What are 3 improvements?

Answer 55

Dual source CT perfusion imaging radiomics

Question 56

How many slice scanners do wide row detectors have?

Answer 56

320

Question 57

What resolution is increased in dual source?

Answer 57

temporal resolution of 83ms due to covering large area in short amount of time

Question 58

What is seen at 80kV?

Answer 58

iodine bone metal

Question 59

What is seen at 140kV?

Answer 59

Plastic uric acid stone fat

Question 60

What is an application of dual energy CT?

Answer 60

Quantification of iodine to visualize perfusion defects in lung air, tissue, iodine defects in myocardium

Question 61

What does CT and PET combine?

Answer 61

Anatomical and functional imaging images fused together

Question 62

When is micro CT used?

Answer 62

studies which minute detail is desired nm

Question 63

When are examples of micro CT?

Answer 63

Tissue engineering enamel thickness & tooth measurement

Question 64

What is nano-CT?

Answer 64

Pixels of 300nm

Question 65

What is industrial CT used for?

Answer 65

QS of materials

Question 66

What aid is used for diagnosis with CT?

Answer 66

computer

Question 67

How do you achieve no noise?

Answer 67

CNN machinery

Question 68

What is radio genomics?

Answer 68

Create imaging biomarkers