Lecture 6 materials - radiogaph Flashcards
How are x-ray images made?
High-energy photons interact with tissue by absorption, transmission, and scatter
X-rays that pass through the patient interact with the detector/film to create a radiograph
What factors affect absorption vs transmission?
Density & tissue thickness, atomic number
As values increase, absorption increases and leads to more opaque (white) areas
What are the 5 radiographic opacities?
Gas (Lucent), Fat (2nd most lucent), Soft tissue & fluid (3rd most lucent), Mineral (2nd most opaque), metal (most opaque)
What type of compound is used to increase contrast?
Barium 56
What causes opacity?
Density, atomic number, object thickness
What is summation?
An increase in opacity due to superimposition of structures that are not in contact
What is border effacement?
When 2 structures of the same radiographic opacity are in contact and their margins can’t be distinguished
What are roentgen signs?
Description of your radiographic finding
Location, Margination, Number, Opacity, Shape, Size
What is an orthogonal view?
Two radiographs that take views that are 90 degrees to each other
What is a cranial-caudal view?
Proximal to the tarsus/carpus
What is a dorsopalmar/dorsoplantar view?
Distal to the antebrachiocarpal/tarsocrural joint
What is a mediolateral or lateral view?
Image travels mediolaterally (medial view to lateral view)
Images also named for the side that is down ‘lateral’ ‘dorsal’
What is craniocaudal view or dorsopalmar/plantar view?
Craniocaudal - extremities proximal to carpus
Dorsopalmar - extremities from carpus to distal
Dorsoplantar - extremities from tarsus to distal
How to make a craniocaudal hanging radiograph
Marker on Lateral side
Proximal up
How to make a lateral/oblique radiograph
Marker on dorsal/cranial side
Proximal up, animal facing left
Why are oblique views important?
They provide angles that may be distorted otherwise (summation, border effacement)
How to accomplish an oblique view
Dorsomedial to palarolateral (DMPLO)
Dorsolateral to Palmaromedial (DLPMO)
What does DLPMO stand for?
Dorsomedial border to Palmarolateral border
What bone of the carpus projects back in a radiograph? What view is this?
Ulnar carpal bone and accessory carpal bone DLPMO
In what view is the first carpal bone projected back?
DMPLO (dorsomedial palmarolateral)
In what view is the 2nd carpal bone and medial splint bone projected back?
Dorsomedial palmarolateral
Where does the majority of bone growth occur?
Metaphysis
What do growth plates look like in a radiograph?
Radiolucent line of cartilage that separates the metaphysis from the epiphysis
Same opacity as soft tissue, leaves an opaque scar when closed
What is the epiphysis
End of long bones, present between the physis and the joint
What is the apophysis?
Tertiary growth center within a bone where ligaments/tendons attach
Does not contribute to bone length (greater trochanter)
What is cortical bone?
Dense lamellar bone
Can you see periosteum and endosteum on radiographs?
Not unless they are diseased
What is trabecular bone?
Spongy bone containing trabeculae (lacy pattern of bone deposition). Found in epiphysis of long bones, short irregulr bones, and most flat bones
What is the medullary cavity?
Inside portion of diaphyseal bone, less radiopaque than cortical bone, contains bone marrow and fat
Where is the nutrient foramen located?
Middle of diaphysis
How to spot articular cartilage
Articular cartilage is thick in younger animals. There will be a radiolucent space in young animals
What types of structures show up with a “soft tissue opacity”
Cartilage, synovium, fluid, ligaments
Does the articulation between the Axis and the Atlas have an intervertebral disc?
No, articulation with the dens
When do spinous processes become more visible on vertebrae?
Cervical 4
How to spot C6 and C7 on a radiograph?
C6 has large transverse processes
C7 has a taller spinous process than other cervical vertebrae
What vertebrae is the anti-clinal vertebrae?
T11
WHere do articular facets begin to change shape?
At T10 and T11
Which vertebrae are ribs named for?
The transverse process with which the articulate
How to differentiate lumbar vertebrae?
Bodies are longer than thoracic vertebrae
Spinous process angled cranially
Transverse process angled cranial and ventral. These should line up on a good angled radiograph
Where can you see diaphragm attachments?
L3 ad L4
What is the radiographic marker for the sacrum?
Promontory
What does the sacrum look like on a radiograph?
Continuous smooth arch between sacrum and ilium
Do thoracic vertebrae have discernable accessory processes?
Yes, T9/T10 to T13 and the first 4 lumbar vertebrae have accessory processes
