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Diagnostic Imaging > Lectures 4-6 (Q1) > Flashcards

Lectures 4-6 (Q1) Flashcards

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1
Q

What is the radiopharmaceutical used in Scintigraphy?

A

Technetium

(99mTc)

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2
Q

What are the main clinical applications of Scintigraphy (5)?

A
  • Bone scans → lameness evals
  • Thyroid scans
  • Parathyroid scans
  • Renal scans
  • PSS studies
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3
Q

What agent is used for bone scans?

A

MDP

(Methyline Di-Phosphate)

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4
Q

What does MDP bind to in bones?

A

hydroxyapatite crystals

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5
Q

What is MDP localization in bone dependent on?

A

Depends on the rate & extent of bone remodelling and blood perfusion

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6
Q

What is the drawback of scintigraphy?

A
  • Not very specific (but is highly sensitive)
  • Lesions can be ID easily but can’t DX w/o using further techniques
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7
Q

List the safety concerns you must take into account when using MDP.

A
  • Protective gear (i.e. gloves, etc)
  • Remains in the urine for 48 hrs.
  • Need to keep the animals in controlled areas to prevent exposure to non-protected individuals
  • Will have contaminated bedding & kennels
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8
Q

List the 3 Imaging Phases of a Bone Scan.

A
  • Phase I: Vascular or pool phase
  • Phase II: Soft tissue phase
  • Phase III: Bone phase
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9
Q

Characteristics of the Vascular phase of a bone scan?

A
  • Area imaged = vasculature & extravascular fluid
  • Very short phase
  • Only 1 area can be imaged
  • Best real-time
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10
Q

Characteristics of the Soft tissue phase of a bone scan.

A
  • Distributed in the ECF of all body tissues
  • Occurs 1- 15 min post injection
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11
Q

Characteristics of the Bone phase of a bone scan.

A
  • IDs pathological increases in blood flow & bone pathology
  • Occurs 2-4 hrs. post injection
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12
Q

How is the image formed in Scintigraphy?

A
  • Gamma camera records radiation emitted from P
  • Photomultiplier tube inside the camera transforms the light into an electric signal
  • Intensity of radiation = pixel brightness
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13
Q

What is proportional to Tc uptake in Scintigraphy?

A

Tc uptake is proportional to the intensity of radiation

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14
Q

What is a “hot spot” on Scintigraphy?

A

An area of increased uptake =

increased bone/soft tissue activity

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15
Q

What does 99mTcO4 allows you to visualize?

A

Thyroid morphology

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16
Q

What does 131I or 123I allow you to visualize?

A

Thyroid fxn

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17
Q

Which organ should show similar

uptake to the thyroid?

A

the salivary glands

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18
Q

What is Fxnal Renal Scintigraphy used for?

What is the radiopharmaceutical used?

A
  • GFR calculation
  • 99mTc-DTPA
    • Diethylene triamine pentaacetic acid
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19
Q

What % of 99mTc-DTPA is boung to plasma proteins?

A

5-10%

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20
Q

What radiopharmaceutical is used for

Scintigraphy of PSS?

A
  • Sodium 99mTc-pertechnetate → trancolonic/transsplenic scintigraphy
  • <strong>99m</strong>Tc-mebrofenin → transsplenic scintigraphy + liver fxn assay
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21
Q

Where will the radiopharmaceutical accumulate in a normal patient in a PSS Scintigraphy?

A

In the liver

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22
Q

Where does the radiopharmaceutical accumulate in PSS patients?

A
  • Predominately in the cardiac chambers
  • Minimal to no uptake in the liver
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23
Q

How is Leukoctye Scintigraphy used in Equines?

A

to ID foci of inflammation

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24
Q

How are Scintigraphic Ventilation-Perfusion studies utilized?

A

To evaluate Ventilation/Perfusion matching

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25
How is **MMA** (macro-aggregated albumin) used?
To visualize the perfused lung → gets stuck in pulmonary capillaries
26
How is **DTPA** (Diethylene triamine pentaacetic acid) used?
Aersolized and visualizes the lung paranchyma
27
What is the advantage of Scintigraphy?
More sensitive & can pick up bony changes before they are visible with radiographic methods (Rads, CT)
28
What does **SPECT** stand for?
Single Proton Emission Computed Tomography
29
How is SPECT different from Scintigraphy?
2 gamma cameras rotate around the P & takes images @ multiple positions along the 360° circle
30
How are SPECT images often studied? Why?
* DUAL studies = scintigraphy overlayed on CT or MRI * to improve anatomic accuracy & improve spatial resolution
31
What does PET scan stand for?
Positron Emission Tomography
32
What type of energy is recorded by PET scan detectors?
anihilation radiation | (sounds dangerous!)
33
Anihilation radiation produces ____ photons that are emitted in _______ direction.
* TWO * exactly opposite directions (180° from each other)
34
What is the advantage of PET scans?
* PET detectors are more sensitive & thus can detect very subtle pathologies * Functional imaging → agent accumulates in areas w/ high glucose metabolism (1° tumor & their metastasis) * Can study brain fxn
35
Essential Radiographic Techniques?
* Appropriate exposure * High definition film/screen combo * Use standard positioning techinques * Take at least 2 views * Collimate to the area of interest * Use sedation or GA if needed * Label appropriately * Use the same projections & exposure for follow up studies
36
Label the parts of a long bone
37
What supplies blood to normal, healthy bone? (3)
* Centrifugal from the **medullary artery** (~ 2/3 of blood supply) * **Periostal vessels** * **Epiphyseal vessels** → immature animals
38
Characteristics of Woven Bone?
* Unorganized structure * Formed in fetal life & during skeletal repair * "Fracture callus" * Replaced by lamellar bone during remodelling * Makes up the skeleten of lower vertebrates
39
Characteristics of **Lamellar Bone**?
* Orderly structure * Slower rate of formation * Occurs later in fracture healing
40
Which type of bone *lacks* radiographic density?
Cancellous/Trabecular/Spongy bone
41
Which form of bone is more dense radiographically?
Compact or Cortical bone
42
What leads to the development of flat bones?
Intramembranous ossification
43
Periosteal membrane around \_\_1\_\_ bone lays down \_\_2\_\_ laminae.
1. Tubular (diaphyseal) 2. Concentric
44
How do the cells differentiate in **Endochondral ossificaiton**?
along a Chondrogenic pathway
45
How do long bones gain length?
Endochonral bone growth along growth plates
46
Where is the **physeal plate** located?
Btwn the epiphysis & metaphysis
47
Where is the **Epiphyseal Plate** located?
Beneath the surface of Articular cartilage
48
Where are the **1° Ossification Centers** located?
Diaphyses | (middle of bone)
49
Where are the **2° Ossification Centers** located?
* Epiphyses (ends of bone) * Metaphysis
50
Where are the **Traction Centers** (3° Ossification center) located?
Apophyses
51
The metaphyseal width \_\_1\_\_ immediately to the width of the \_\_2\_\_ as it grows shaftward.
1. decreases 2. diaphysis
52
What is the **"cut back" zone**?
* Site of marked modeling in width in the Metaphysis→ cortical margin is irregular * Has a roughened cortical/periosteal border * In young, growing animals
53
How do growth plates appear on rads?
appear poorly organized
54
Give some examples of **3° Ossification Centers**.
* Supraglenoid tubercle scapula * Olecranon * Medial epicondyle of the humerus * Trochanter tertius femoris * Tibial apophysis * Tuber calcis * Tuber coxae
55
What are the weakest parts of developing bone? Consequence?
* Physes * Physeal FXs are common in young P
56
What does the shape of the physis partially determine? (In regards to FXs)
Type of Salter-Harris FX
57
What commonly occurs after injury to the physis?
* Malformations of bone growth * abnormal length, shape, contour
58
Damage to the **Ulnar Physeal plate** (btwn the epiphysis & metaphysis) can cause what?
Premature closure of the growth plate → shortened ulna →cranial bowing → angular limb deformities
59
Describe the different types of **Salter Harris FXs** (Type I - V)
60
List the 6 different types of **Periosteal Rxns.**
* Smooth, well defined * Parallel/Lamellar → "onion skin" * Brush border * Palisading * Irregular, ill defined * Radiating → "sunburst"
61
What type of Periosteal Rxn is this? 3 Rule outs?
* Lamellar or "Onion skin" periosteal rxn * Ewing's, osteomyelitis, or osteosarcoma
62
What type of Periosteal Rxn is show here? (lateral aspect of 5th metacarpal & digit)
Palisading Periosteal rxn | (ex. hypertrophic osteopathy)
63
What type of Periosteal Rxn is seen here?
Sunburst Periosteal Rxn | (often highly aggressive)
64
What type of Periosteal Rxn is seen here (arrows)?
* Codman Triangle * Osteosarcoma, Ewing sarcoma, osteomyelitis, metastasis, chondrosarcoma ormalignant fibrous histiocytoma
65
Characteristics of **Benign Bone Lesions**?
* Short zone of transition * **distinct margins,** **sclerotic border** * Intact cortex * Intact, smooth periosteal new bone * Slow changes in appearance
66
Characteristics of **Malignant Bone Lesions**?
* Long zone of transition * I**ndistinct margins, less dense border** * Interuppted cortex * Interuppted, irregular periosteal new bone * Changes appearance rapidly
67
Is this lesion benign or malignant?
Benign
68
Is this lesion Benign or Malignant?
Malignant
69
What should you always do in conjunction when assess bone lesions?
Assess the surrounding soft tissue
70
When do **Pathological FXs** often occur?
spontaneous or following minor trauma to a weakend bone
71
Which animals get **Fatigue FXs**? Where do these fxs typically occur?
* Racing animals → horses & greyhounds * Metacarpals & metatarsals
72
What can mimic FX lines? (7)
* Nutrient foramina * Overlying fascial plane fat * Gas in the fascial plane in open FXs * Normal growth plates * Skull sutures * **Mach lines** * Artefact from a damaged grid
73
What is the only way that FX lines can be visualized radiographically?
if they are aligned PARALLEL to the X-ray beam (it passes directly through them)
74
Increased opacity of the cortex and medulla can be indicative of what 3 things?
* Folding FX * Impaction * Overriding FX ends
75
What is the best way to confirm a **Chip FX**?
Radiograph the opposite limb & compare
76
List the 4 different criteria used to classify FXs.
* Morphology * Cortical involvement * Fragment shape * Articular/physeal involvement
77
What type of FX line is demonstrated here? What typically causes this type in animals?
* Comminuted FX w/ a **Transverse FX line** * High energy trauma → HBC
78
What type of FX line is seen here?
Oblique FX line
79
What type of FX line is seen here?
Spiral FX line
80
What are Comminuted FXs?
* Have at least three fracture fragments & the fracture lines interconnect. * The individual fracture lines that form the comminuted fracture may be transverse, oblique, or spiral.
81
What type of FX is seen here?
Comminuted FX
82
What type of fracture is seen here?
**Butterfly FX** (fragment)→ type of Communited a bone break in which the center fragment is contained by two cracks & forms a triangle.
83
What type of FX is shown here?
Multiple segmental FX | (type of Comminuted FX)
84
How do **Avulsion FXs** typically occur?
when a fragment of bone tears away from the main mass of bone as a result of physical trauma (often at the site of tendon & ligament attachement)
85
What type of FX is seen here?
Avulsion FX
86
What type of FX is seen here?
* **Greenstick FX** * occurs when a young, soft bone * One side bends and the other side breaks
87
Which **Salter-Harris Type** is shown here?
Salter-Harris **Type I** | (seperation @ the level of the physis)
88
What Salter-Harris Type is shown here?
Salter-Harris **Type II** | (involves the physis & metaphysis)
89
Which Salter-Harris Type is seen here?
Salter-Harris **Type III** | (involves the physis & epiphysis)
90
Which Salter-Harris Type is seen here?
Salter-Harris **Type IV** (involves physis, metaphysis & epiphysis)
91
Which Salter-Harris Type is seen here?
Salter-Harris **Type V** (crushed/compressed physis) (May not be visisble @ time of injury) (May lead to abnormal growth/deformity)
92
What type of physeal FX is seen here?
Salter-Harris **Type VI**
93
What type of Physeal FX is seen here?
Salter-Harris **Type VII** (AKA Ogden VII) * Isolated to the epiphyseal plate→ does NOT involve the physis * May be an avulsion fx
94
What are the features of a **Pathological FX**?
* Cortical thinning or destruction * Medullary bone cystic/destruction * Periosteal new bone is present * Shape/pattern/direction of FX line is unusual * Bone shape is often abnormal
95
What is the likely cause of this fracture?
Pathologic FX
96
Etiology of **Sesamoid Bone Dz**?
* Congenital → bipartite sesamoid bones * Traumatic → nonunion FX * 2° changes → Modeling following arthrosis
97
How do you initally assess a FX? (8 questions you should be asking yourself)
1. Location * which bones are involved? where on the bone? 2. Age of FX * sharpness of FX ends? signs of bone healing or callus formation? 3. Type of FX 4. Displacement of the Fragments * Distracted? Impacted? or Overriding? 5. Bone radiolucency or loss of normal architecture? 6. Joint involvement? 7. Foreign material present? 8. Soft tissue changes? 9. Other injuries elsewhere in the body?
98
What can help you determine the age of a FX?
* Margin of FX fragment * Fragment density * Fracture gap * Callus formation * Periosteal rxn?
99
Signs of an **ACUTE FX.**
* Sharply, delineated fx margins * Persistent "normal" bone density * Wide fracture gap * No callus formation
100
Signs of a **Chronic FX**?
* Indistinct, rounded fx margins * Loss of bone density * Bridged fx gap * Callus formation
101
Describe the steps of **FX healing** in chronological order.
1. Blurring of FX lines → bone resorption 2. Widening of FX gap → bone resorption 3. Formation of endosteal & periosteal callus 4. Progressive bridging of FX gap & decreased luceny 5. Remodelling of the callus → becomes smoother & smaller 6. FX gap no longer visible
102
What is the relationship btwn calluls formation and bone stability?
More stability = less callus formation Less stability = more callus formation
103
How can plates potentially complicate FX healing?
Plate provides stress protection → reduces the load on the bone → weakens the bone (instead of strengthening it) → may lead to reFX
104
Periosteal tearing can lead to a _________ and complicate FX healing.
Bucket handle callus
105
How can non-anatomic reduction complicate FX healing?
* Malunion * Non-union * Hypertrophic * Atrophic
106
How does an **Atrophic Non-Union** appear on a radiograph?
* Pointed FX ends * No callus formation visisble * No osseous bridging of FX gap
107
What is the 1/2 life & carrier molecule of Technetium?
Half life = 6 hrs Carrier = MDP

Diagnostic Imaging (5 decks)

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