Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Musculoskeletal > Ortho Introduction to Radiology > Flashcards

Ortho Introduction to Radiology Flashcards

1
Q

X-Ray Properties

A

high energy electromagnetic waves that pass through a body part onto a film
Most of the radiation is passed through the body, but some is absorbed producing the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 factors of radio-opacity

A
  1. atomic number: higher is more radiopaque
  2. physical density: air (black), fluid and soft tissue (grey), bone (white)
  3. Thickness: thicker structures result in more attenuation, more radiopaque
    Overlapping structures will be additive and appear more radiopaque than if they were separate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

General Opacities

A
  1. Mineral opacity
  2. Soft tissue/fluid opacity
  3. Fat opacity
  4. Gas Opacity
  5. Metal Opacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

X-Ray Components

A

Electrode pair, glass vacuum tube in a lead case
Cathode generates electrons that strike the tungsten anode
Electron collides with tungsten atom knocks an e- out of a lower orbit
When a higher orbital electron falls to fill the gap, energy is released as a photon (x-ray)
95% of energy is deposited as heat, only 5% generates x-rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Digital radiography

A

Photostimulable plate absorbs x-rays and emits light (flourescence) that is detected by an image reader

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Flat Panel Detectors

A

most common
Amorphous silicon: x-ray converted to light, which is converted digital output signal (indirect image)
Amorphous selenium: x-ray photons converted directly into charge on a sensor (direct image)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

High Density Line Scan Solid State Detectors

A

Phosphor detectors records X-ray energy during exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Radiation Protection

A
  1. Reduce time of exposure
  2. Increased distance from radiation source
  3. Radiation shielding (lead shields)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Scanograms

A

Measure leg lengths precisely

Used in children if correction is necessary to equalize growth of legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Comparison X-Rays

A

When comparing left to right

Done to verify a fracture in a pediatric patient (compare epiphysis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Stress X-Rays

A

Usually done to assess ligamentous stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Arthrogram

A

Contrast is injected into a joint capsule and a radiograph is taken
If the contrast extraverts then the capsule has a tear in it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Myelogram

A

Image the subdural space

Useful in diagnosing spinal stenosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many views are needed when doing conventional x-ray exams?

A

Radiographs provide a 2D image

3D must be reconstructed mentally (from orthogonal projections, need at least 2 views)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Orthogonal projections

A

two radiographic projections made at right angles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

X-Ray Naming

A

Direction primary beam enters and leaves the tissues being examined (AP)
Position of the patient (prone, supine, seated, standing) during exposure, left/right markers identified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Radiographic planes

A
  1. Median or midsagittal plane
  2. Coronal plane
  3. Axial or transverse cross-sectional plane
18
Q

Computed Tomography

A

Fanned x-ray beam rotated around a patient is measured by a series of detectors
Measurement of transmission at different angles allows computation of an image
Image densities are the same as conventional X-rays
Density and contrast varied by varying amount of radiation and time of exposure
Good for viewing fractures

19
Q

Ultrasonography

A

Displays an image based on acoustic properties of the tissue
Sound waves are sent into a patient and returning echo is converted into an image
Resolution depends on wavelength and frequency of waves

20
Q

Types of Ultrasound

A
  1. Low frequency-longer wavelength, less resolution, greater depth of penetration
  2. High frequency-smaller wavelength, greater image detail, superior for images of tendons, ligaments and bone
21
Q

High Frequency US

A

Better for tendons, ligaments and bone
Smaller wavelength
Greater image detail

22
Q

MRI

A

Tissue in magnetic field causes magnetic moment spin of hydrogen nuclei to line up
Deflecting the nuclei from this orientation using RF signals causes protons to emit RF signals that are used to generate images
Good for soft tissue contrast
Good for bone marrow, cartilage, soft tissues, ligaments, muscle and fat

23
Q

T1

A

Measures energy released as proton exposed to RF signal realigns to magnetic orientation
Fat and muscle appear different on T1 (visualize fluid better)

24
Q

T2

A

Measures energy transmitted by the wobbling effect of protons that have been exposed to RF signal (they are out of phase and release energy as they become in phase “larmor frequency”
2nd RF blast is used
Normal muscle and striated muscle appear different on T2

25
Q

Radio-isotope absorption

A

Tissues with increased circulation will receive more isotope

26
Q

Strontium 85

A

1961

1st isotope used for bone scanning

27
Q

Strontium 87

A

Shorter half life, poor soft tissue clearance

28
Q

Technetium tc99

A 
1971
Short half life
Excreted into urine 4 hours post injection
Administered as phosphate complex
Binds with Ca2+ in bone
29
Q

Indium 111

A

leukocyte scan

Used to tag WBCs and assess uptake into areas of infection (useful in osteomyelitis)

30
Q

Gallium 67

A

impregnates into Ca2+ hydroxyapatite crystals
Uptake in neutrophils and bacteria
Track progression of treatment of infection

31
Q

Factors that affect uptake of isotopes

A
  1. Bone turnover rate
  2. Blood flow to trauma
  3. Trauma
  4. Time isotope is in the system
32
Q

PET

A
  1. metabolic imaging (good for diagnosing tumors)
  2. Tracer is used to measure the rate of glucose absorption by tissue
  3. Accumulation rate reflects glucose utilization in tissue
  4. Based on increased glycolytic rate in pathologic tissues
33
Q

Advantages of PET

A

high sensitivity for bone pathology, allow imaging metabolic activity, white cell scintgraphy used to dx osteomyelitis, scintigraphy used to dx metastsis, stress fx, occult fx, etc

34
Q

Disadvantages of PET

A

Lack of detail and special resolution
Limited early sensitivity to detect acute fx in patient with slow bone metabolism, low sensitivity with lytic diseases (multiple myeloma)
Low specificity for bone pathology

35
Q

DEXA Scan

A

Dual energy X ray absorption
Measures absorption of 2 beams of radiation into hip and spine
Results are compared to standard
T-scores calculated and used to identify if patient has osteopenia or osteoporosis
Measures bone mineral density

36
Q

Dexa scan values

A

Osteopenia-T-score at or below -2.5
Severe osteoporosis-T-score at or below -2.5 and history of one or more fractures
Normal T-score -1 and above

37
Q

BMD differences

A

20-40 for healthy caucasian women
One standard deviation on either side represents 68% of population
85% of women 20-40 have normal BMD

38
Q

CT Advantages

A

Better cross sectional capability

39
Q

Bone Scan Advantages

A

Early detection of fracture
Stress fracture, can be positive as early as 48 hours post injury
Detection of infection and degree of involvement

40
Q

MRI

A

Bone contusion
Articular cartilages
Relationships of neurovascular structures to other anatomy

41
Q

Ultrasound advantages

A

Fluid filled tissue and vascular supply

Musculoskeletal (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions