Exam 2 Flashcards
What is the defining characteristic of ultrasounds?
Benefit of real-time imaging
A second benefit to ultrasound is the ability to do what?
Move the diagnostic probe in any direction
What is not a factor in ultrasound?
Use of ionizing radiation
The probe on an ultrasound is also known as the _____
Transducer
Speed of sound varies with _____ of tissues
density
What ultrasonic mode is associated with brightness?
B-Mode
If pixels are bright they are ________
Hyperechoic
If pixels are dark they are ______
Hypoechoic
What ultrasonic mode is associated with motion?
M-Mode
__-mode creates __-mode
M-mode creates B-mode
Shows the image of the flow of blood and other liquids
Doppler
In color flow Doppler imaging, the information collected is presented as a color overlay on top of a __-___ image
B-image
In the color flow Doppler, blue moves ____ the probe and red moves ____ the probe
Blue moves away from the probe, and red moves toward the probe
Change shape with eletrical current
Piezoelectric ceramics
_______ in ceramics emit a mechanical vibration at a preset frequency
Crystals
Sound frequency emitted is usually set anywhere between __ and ____ megahertz (MHz)
2 and 18
What is the sound frequency set for opthalmic studies?
Up to 50 MHz
Sound waves do not travel through ___
Air
What is digitized to create a diagnostic image?
Electrical current
There is an inverse relationship between increasing the ______ output and the maximum ____ it can scan
frequency, depth
The higher the frequency the ______ it will penetrate
less
The higher the frequency the ____ the lateral spatial resolution
higher
Where is lateral spatial resolution best?
Near probe
Transducer with flate contact surface and fine detail imaging
Linear transducer
Transducer used for general scanning, aka sector prober or curvilinear
Convex Transducer
Transducer similar to convex but smaller, used for small patients and intercostal studies
Microconvex transducer
Transducer that creates 3D images
Matrix transducer
Transducer containing piezoelectric elements that are stimulated in complex timing sequences, steered through firing time delays. Most used for cardiac studies.
Phased Array Sector Transducer
What are ultrasounds used for in bovine/ruminants?
Reproductive and biopsies
What are ultra sounds used for in equine?
Tendon and ligament injuries and fertility
What are ultrasounds used for in porcine?
Back fat levels
Artifacts that are created by air pockets, metallic objets, foreign body
Comet tails
Artifact caused by redirection of sound, associated with curved fluid-filled structures such as the gall bladder, urinary bladder, cysts and sometimes kidneys
Edge shadowing
This artifact occurs when the sound beam travels through weakly attenuating structures such as as bladder with fluid
Acoustic enhancement
In acoustic enhancement artifacts, the reflection appears brighter at the ___ side of the structure
Far side
Artifact that occurs when sound beam reflects back from the surface between two structures and the machine misinterprets it and places a mirror image on one of the structures
Mirror image
Artifact resembling the northern lights, caused by repeated reflection of echoes trapped between two strong reflectors (ie. gas filled loop of bowel)
Reverberation
Artifact that occurs when sound beam hits a dense object (such as a bladder stone), sound beams are reflected away and are absorbed creating dark streak or shadow
Acoustic shadowing
Use the magnetic field and radio frequencies to determine the chemical makeup of a substance
MRI (Magnetic Resonance Imaging)
Shows concentration of free-floating hydrogen molecules in tissue, much better contrast than CT
MRI
MRI’s are superior in demonstrating what structures?
Brain, spinal cord, and soft tissue structures (ligaments and cartilage)
MRI’s _____ (do or don’t) use ionzing radiation
Do not
Molecules in an MRI align based on their _____ and become magnitized
polarity
MRI’s are tuned to the frequency of what?
Hydrogen atoms in molecules
Magnet with two slabs facing each other, with lower field strengths
Permanent magnet
Low field magnets with electrical charge through copper wiring wrapped around a center
Electromagnets (resistive magnets)
Most common magnet, superconductive in very low temperatures. Massive electromagnet.
Superconducting magnets
Nuclear medicine is divided into what two groups?
Therapeutic and diagnostic
Administration of radioactive iodine for the treatment of hyperthyroidism and thyroid tumors
Veterinary therapeutic nuclear medicine
Administration of radionucleotides to the patient and detection of the electromagnetic radiation emitted from the patient via a gamma scintillating camera
Diagnostic nuclear medicine
In nuclear medicine _____ is attracted to bone
Technetium Tc 99m
In nuclear medicine ______ is attracted to the thyroid gland
Iodine I 131
What isotopes in nuclear medicine are used in horses?
Technetium Tc 99m
Half life of technetium 99m and protocol
6 hour half life, 24-48 hours protocol
Nuclear medicine waste products need to be kept in lead line container for __-___ hours
24-48
Minimum views required for pelvis and pelvic limbs
Two views
When radiographing pelvis/pelvic limbs, high ____ is preferred
contrast
When radiographing pelvis/pelvic limbs ____ __ technique is preferred
Table Top
What routine views are used for pelvis?
Lateral, Ventrodorsal hip extended
What routine views are used for the femur?
Lateral, craniocaudal
What routine views are used for the stifle?
Lateral, caudocranial
What routine views are used for the tibia/fibula?
Lateral, caudocranial
What routine views are used for the foot (tarsus/metatarsus/digits)?
Lateral, plantardorsal
The main required view for pelvis radiograph (OFA)
VD hip extended for coxofemoral joint
What pelvis radiograph is needed to determine the laxity in coxofemoral joints
PennHIP
At what age can OFA’s be submitted?
2 years or older
How are OFA’s rated?
Excellent, good, fair, or poor
What must be included in an OFA view?
Pelvis bilaterally symmetrical
Patellas and stifle joints included
Last three lumbar vertebrae
Femurs parallel with equal ischial overlap
Patellas centered in femoral groove
What three views must be included for PennHIP?
Extended VD
Compression
Distraction
What do compression views measure?
the extent to which the femoral head fits within the acetabulum
What do distraction views measure?
the amount of passive laxity inherent in the joint
At what age can PennHIPs be taken?
16 weeks
What reasons do we send in PennHIP for?
Joint laxity
CHD (Canine hip displaysia) and oestoarthritis
DJD (Degenerative joint disease)
How many views are required for small animal forelimbs?
2
What limbs are routinely radiographed lateral and caudocranial?
Shoulder, scapula, humerus
What limbs are routinely radiographed lateral, and craniocaudal?
Elbow, radius, ulna
What two routine views are done for the foot?
lateral and dorsopalmar
What is measured for the lateral and craniocaudal scapula view?
cranial scapula border
Where is the central ray positioned for the shoulder joint?
Scapulohumeral articulation
What are the borders for the shoulder joint?
Proximal third of humerus and scapula
What are the borders for the scapula?
Shoulder joint and caudal border of the scapula
For the pelvis measurement, the caliper should be placed _______
Laterally
The caliper measurement is used to determine _____ for both lateral and VD pelvis radiograph
kVp
Where is the primary beam centered for a pelvis radiograph?
Centered over hip joints
For a pelvis lateral view, the lower leg should be pulled slightly _______
cranial
For a pelvis lateral view include entire ______, portion of the _____ _____ and most of the _____
Pelvis, lumbar spine, femur
What view should be used when pelvic trauma is suspected?
Frog leg view
In frog leg view, femur should be flexed at _____ degrees
45 degree angle
What pelvic view puts minimal stress on pelvis?
Frog leg view
Where should the beam be centered for a VD view of the pelvis?
Over level of pubis and acetabulum
Where should the measurement be taken for a VD view of the pelvis?
Over the acetabulum
