Term
| If general anesthesia is used for a skull x-ray what needs to be done before taking the film? |
|
Definition
| Pull the endotracheal tube. |
|
|
Term
| What are the four routine views for a skull study? |
|
Definition
1) Open-mouthed lateral
2) D/V
3) Right oblique
4) Left oblique |
|
|
Term
| Positioning for lateral skull film. |
|
Definition
| Lateral recumbency with the affected side toward the cassette. Mouth open, nasal septum parallel to cassette, mandibular rami and tympanic bulla should be superimposed. |
|
|
Term
| Positioning aid in lateral skull film? |
|
Definition
| Foam pad under the mandible |
|
|
Term
Landmarks of lateral skull film?
Center?
Measure? |
|
Definition
Landmarks-Entire head from the tip of the nose to the base of the skull
Center-lateral canthus of the eye
Measure-over the high point of the cranium |
|
|
Term
|
Definition
| Sternal, mandible of the animal resting on the table naturally, mouth closed, front legs outside of the field of view but cranially in a natural position |
|
|
Term
| D/V skull positioning aid? |
|
Definition
|
|
Term
D/V skull
Landmarks?
Measure?
Center? |
|
Definition
Landmarks: Tip of the nose to the base of the skull
Measure: Thickest point of the cranium
Center: Lateral canthus of the eye |
|
|
Term
|
Definition
| Dorsal recumbency, front limbs extended caudally, nose parallel to cassette |
|
|
Term
| V/D skull positioning aids? |
|
Definition
| V trough or sandbags, foam wedge placed under neck to keep the skull on the cassette |
|
|
Term
V/D skull
Landmarks?
Measure?
Center? |
|
Definition
Landmarks: Entire head from the tip of the nose to the base of the skull
Measure: Lateral canthus of the eye
Center: Lateral canthus of the eye |
|
|
Term
|
Definition
| Right lateral recumbency for left obliques, Left lateral recumbency for right obliques, Skull naturally obliqued toward the table 30-40 degrees with tape or gauze roll to keep mouth open to separate the mandible and maxilla |
|
|
Term
|
Definition
| Label the mandible that will appear on top |
|
|
Term
| The best view for tympanic bullae is? |
|
Definition
| open-mouthed rostrocaudal |
|
|
Term
| When radiographing the skull in the dorso-ventral position, it is important to? |
|
Definition
| Remove the endotracheal tube before making the exposure |
|
|
Term
| A left 20 degree ventral/right dorsal oblique projection of a dog's skull is made. Which tympanic bulla would be more ventral on this film? |
|
Definition
|
|
Term
| For a DV view of the entire skull, you should center the primary beam? |
|
Definition
| Between the lateral canthi on the sagital crest |
|
|
Term
| To ensure that your DV radiograph for the skull is parallel and perpendicular, you should try to have? |
|
Definition
| An imaginary line drawn between the medial canthi be perpendicular to the film |
|
|
Term
| You are required to take intraoral radiographs of the teeth of a Labrador. You are to use a regular x-ray machine because you do not have a dental unit. The animal is anesthetized. You should use? |
|
Definition
|
|
Term
| A veterinarian is performing a radiographic survey of a cat's skull to evaluate the trabecular bone in the nasal cavity for a nasal tumor (producing asymmetry). Knowing that ultra fine detail is needed, which of the following equipment would best allow for a diagnostic study? |
|
Definition
| Slow screen and film combination |
|
|
Term
| An open-mouth, end-on radiograph highlights? |
|
Definition
|
|
Term
| Ultrasound was developed from what? |
|
Definition
| Sonar used in submarines in WWII |
|
|
Term
| Name three organs that are easily seen in ultrasound, but not on radiographs. |
|
Definition
1) Prostate
2) Spleen
3) Kidneys |
|
|
Term
| Ultrasound is the best modality to evaluate what type of organs? |
|
Definition
| Fluid-filled and soft tissue organs (bladder, hearts, reproductive tracts) |
|
|
Term
| What are five advantages of ultrasound? |
|
Definition
1) Portable
2) Does not require ionizing radiation
3) Non-invasive
4) Well tolerated by patients
5) Accepted by owners |
|
|
Term
| Why is a coupling agent needed and what are some examples? |
|
Definition
| Agent allows sound to pass from the transducer directly into the body without interference from air. Gel, saline, water |
|
|
Term
| What in the transducer transmit the electrical impulses? |
|
Definition
|
|
Term
| What Hz does ultrasound operate at? |
|
Definition
| 3-10 MHz (million cycles per second) |
|
|
Term
| How is an image produced by an ultrasound? |
|
Definition
| Sound waves travel thru the body and reflect back to the transducer called echoes; the sound waves are analyzed by the computer, converted to electrical impulses and displayed on the screen producing a grey scale image |
|
|
Term
| What produces the grey scale effect? |
|
Definition
Returning sound waves have different intensities because tissues have different acoustic properties, or acoustic impedance
1) air scatters sound
2) Water transmits sound with little attenuation or reflection
3) Mineral and metals are highly reflective
4) Sound cannot penetrate bone |
|
|
Term
| What is the definition of acoustic impedance and what does it depend on? |
|
Definition
Definition: Ability of a living tissue to resist or impede the transmission of sound.
Depends on the density and elasticity of the tissue. |
|
|
Term
| Sound travels in pulses called? |
|
Definition
| Propagation speed/velocity |
|
|
Term
| On what organ are U.S. ultrasounds calibrated on? |
|
Definition
| The human liver at 1540 meters per second |
|
|
Term
|
Definition
| The distance that a wave must travel in one cycle. Shorter than audible sound but longer than x-ray. |
|
|
Term
|
Definition
| The number of cycle per unit of time (seconds). As the frequency increases the length of the wavelength decreases. Commonly 2-10 million Hertz or cycles per second. |
|
|
Term
|
Definition
| The speed that sound travels through an object (Velocity=frequency x wavelength). When the sound waves return the computer records the time that the echo took to return to calculate the depth at which the sound was reflected. |
|
|
Term
| Define acoustic shadowing. |
|
Definition
| The lack of echos below a reflective area like bone or air because the sound waves do not penetrate and are reflected back up to the transducer. This gives you a black area and no information deeper than the bone. |
|
|
Term
|
Definition
| No echoes are detected or reflected back, and the area is black. Typically associated with fluid-filled structures like a urinary bladder. |
|
|
Term
|
Definition
| Tissue reflects back few echoes. Area appears darker than surrounding tissue. Reflects less sound back than the area of tissue around it, such as a tumor with necrosis. |
|
|
Term
|
Definition
| A dense structure in the ultrasound image that appears bright or white compared with adjacent structures. A bladder stone is hyperechoic. Also called echogenic. |
|
|
Term
|
Definition
| Tissue equal in appearance to that of surrounding tissues. |
|
|
Term
|
Definition
| A single piece of sound information related to the intensity of the signal |
|
|
Term
|
Definition
| Uniform number of echoes throughout such as a normal liver or testicle |
|
|
Term
|
Definition
| The conversion of electrical energy to ultrasound or acoustic energy |
|
|
Term
|
Definition
| The loss of intensity of the ultrasound wave as it travels through tissue |
|
|
Term
| What four things affect attenuation? |
|
Definition
1) Absorption: production of heat as sound passes through soft tissues causing loss of energy
2) Scattering: sound is reflected in different directions
3) Reflection: the return of a part of the ultrasound beam towards the transducer
4) Frequency: sound emitted from a high frequency transducer attenuates faster than sound emitted from a lower frequency transducer. |
|
|
Term
|
Definition
| The part of the machine used to scan the patient. It sends out a series of sound impulses and collects the returning echoes. |
|
|
Term
| What are the two types of transducers? |
|
Definition
1) Pulse wave transducers: short bursts of sound that is emitted and waits until the echo is returned before sending out another.
2) Continuous wave: Contains two transducers. One constantly sends out and the other always listens. |
|
|
Term
| What are transducer crystals? |
|
Definition
| The active element required to promote the conversion of electrical energy to sound waves. |
|
|
Term
| What are the two types of crystals and give two examples of each. |
|
Definition
Natural: quartz, tourmaline, rochelle salt
Synthetic: lead irconate, barium titanate |
|
|
Term
| What are the five types of transducers? |
|
Definition
1) sector
2) linear
3) curvilinear
4) vector
5) endovaginal |
|
|
Term
| A high frequency transducer... |
|
Definition
Increases resolution
Increases attenuation
Decreases penetration |
|
|
Term
| Low frequency transducers... |
|
Definition
Decrease resolution
Decrease attenuation
Increase penetration |
|
|
Term
| Four key components of transducer care. |
|
Definition
1) Avoid hard impacts that will damage the crystals.
2) Broken crystals will show up as black lines on your display.
3) Prevent extreme temperature changes.
4) Some are sensitive to certain cleaning agents. Follow manufacturer directions. |
|
|
Term
|
Definition
| The entire range of frequency. A transducer can produce more than one frequency above or below its center frequency. |
|
|
Term
| Brightness and contrast control |
|
Definition
| should be adjusted so that black, white, and all different shades of gray can be seen. Monitors can be capable of 1,664 shades of gray. |
|
|
Term
|
Definition
| adjusts for the amount of tissue being displayed on the monitor |
|
|
Term
|
Definition
| affects brightness of the image. Increased brightness=higher gain and power |
|
|
Term
| What are the three display modes? |
|
Definition
1) A-mode (amplitude)
2) B-mode (brightness)
3) M-mode (motion) |
|
|
Term
|
Definition
| Amplitude: displays the returning echos as spikes from a baseline. The echo intensity is displayed by the height of the spike. |
|
|
Term
|
Definition
| Brightness: forms the basis for two dimensional imaging. The returning image is displayed as dots on the image screen. Can view in real time as in a beating heart or neonatal animal. |
|
|
Term
|
Definition
| Motion: A continuous display of a thin slice of an organ over time. Produced by passing a narrow sound beam across a body part. Each echo interface is presented as a dot. The motion of the part is displayed by sweeping the image across the screen. Used in echocardiography. |
|
|
Term
| What two scanning planes should be used in ultrasound? |
|
Definition
Sagittal: Long axis; with the transducer held to the cranial or caudal end of the animal
Transverse: (short axis) transducer held 90 degrees to the long axis |
|
|
Term
| How is doppler ultrasound used? |
|
Definition
| Detects moving blood flow in veins and arteries of the body making it possible to watch the flow of blood, hear it, and analyze flow direction, velocity and pattern. |
|
|
Term
| What are the benefits of color flow? |
|
Definition
| Another method to assess flow allowing for visualization of structures not previously identified, such as detecting blood clot, plaque, or tears of the wall lining, etc. |
|
|
Term
|
Definition
Clip hair with 40 blade
Abdomen: xiphoid process to the pubis and from the rib cage to the flanks
Cardiac: area over the heart clipped caudal to the elbow |
|
|
Term
| What are two common artifacts in ultrasound? |
|
Definition
1) Acoustic shadowing: the sound is attenuated at an acoustic interface, preventing the sound from being transmitted to deeper tissues
2) Distant enhancement: occurs when the sound beam traverses a cystic structure and the tissue deep to the cyst appears brighter than surrounding tissues. |
|
|
Term
| Two main uses of ultrasound in large animal medicine. |
|
Definition
1) Pregnancy detection
2) Tendon injury |
|
|
Term
| How do therapeutic ultrasounds work? |
|
Definition
| They elevate the temperature of deep muscle by about 3 degrees, bone 4 degrees, skin does not get hot |
|
|
Term
| What are the six main effects of therapeutic ultrasound? |
|
Definition
1) Increases cellular metabolic rate
2) Vasodilation
3) Increases pain threshold
4) Stimulate cell process that will remove the debris of injury and enhance tissue repair
5) Breaks down scar tissue
6) Phonophoresis: forcing substances through the skin and into the underlying tissue |
|
|
Term
| Therapeutic ultrasound is contraindicated in what six instances? |
|
Definition
1) Can overheat bones and tissue causing pain and burns
2) neoplasia
3) eyes
4) spine
5) brain
6) near growing areas of bone |
|
|
Term
| What does DICOM stand for and what is its purpose? |
|
Definition
DICOM: Digital Imaging and Communications in Medicine
Standard format to save and send images on the integrated computer screens (digital x-rays, ultrasound, etc.) |
|
|
Term
| The ultrasound term that refers to few echoes detected, and the area is a low-level gray compared with the surrounding tissue, is? |
|
Definition
|
|
Term
| The imaging technique that involves a piezoelectric crystal within a transducer is? |
|
Definition
|
|
Term
| Hypoechoic tissues have which of the following characteristics in an ultrasonic study? |
|
Definition
| Reflects few echoes that result in low-level grays on the screen |
|
|
Term
| Which of the following best describes a high-frequency ultrasound unit transducer? |
|
Definition
| Increases resolution and decreases penetration |
|
|
Term
| A bladder stone is hyperechoic. What type of image does this project on the ultrasound monitor? |
|
Definition
|
|
Term
| A urine-filled bladder is usually best classified as? |
|
Definition
|
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