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82 Cards in this Set
- Front
- Back
What are four special concerns w/ equine radiography?
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proper restraint, possible injury to personnel, damage to machine, need more time & patience
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Name two positioning devices for equine radiography
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positioning block and cassette tunnel
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What is the most common type of xray machine for equine?
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portable
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What is the most common cassette size for equine xray?
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10x12
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What are three machine options for equine xray?
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small portable, mobile unit, mounted unit on rails
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Four safety considerations for equine xray?
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protect personnel 1st (equip 2nd), take safest view possible, avoid views from behind rear leg, never hold xray tube
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Why is labeling esp important for equine xray?
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all legs look the same from cannon bone distally
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3 technique consideration for equine xray?
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clean debris from area of interest, pick foot & pack w/ playdough, and views of joints should be done weight bearing
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Why are special contrast techniques needed?
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give more info than flat films, used to highlight a lesion, increases contrast w/i a specific organ
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What are two types of contrast media?
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pos and neg
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What type of contrast media makes area white?
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Positive
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What type of contrast media makes area black?
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Negative
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Give 2 examples of positive contrast medias
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Organic Iodine & Barium
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What contrast media is used for excretory urography, angiography, and cystography?
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Organic Iodine
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What contrast media is usually used for the GI tract? When would it not be used and what would be used in its place?
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Usually barium, but contraindicated if perforation suspected - then iodine would be used
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Examples of neg contrast medias
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room air, oxygen, CO2, nitrous oxide
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What 2 neg contrast medias are safer because they are easily absorbed and have lest chance of air emboli?
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CO2 and nitrous oxide
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What type of contrast media is used for pneumocystography, double contrast studies, and pneumography?
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Negative
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What contrast media has side effect or air embolism?
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Air
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What are some side effects of iodine?
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nausea, allergic reaction, anaphylactic reaction, hypotension, and shock
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What are some side effects of barium?
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aspiration (make sure tube is in stomach), peritonitis (from perforation - leaks into abdomen)
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What change of exposure technique is used w/ contrast media?
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Increase MAS by 30%
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Describe general patient prep for abdominal study & what views taken?
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fast for 12-24 hours if possible, enema 4 hours prior, VD and right lateral views taken
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When is excretory urography indicated?
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to check kidney function and size
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What is procedure for excretory urography?
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place indwelling IV catheter, give bolus injection of iodine contrast agent, take films
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What are the 3 phases of excretory urography?
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nephogram (see renal vasculature), pyelogram (see renal pelvis), drainage phase (see ureters)
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When is cystography indicated?
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to examine bladder wall for abnormalities or tears
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What are 2 precautions for cystography?
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don't over fill bladder - it can rupture, use nitrous rather than air because of air embolism
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What is the procedure for cystogram?
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sedation necessary, do survey films first, clean penis, pass urinary catheter, remove urine, infuse contrast agent until bladder is moderately full
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Name and describe 3 kinds of cystograms
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pos contrast (iodine), pneumocystogram (gas), double contrast (both)
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When is a urethrogram indicated?
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to examine internal structure of urethra
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Name the 2 types of urethrograms
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retrograde and antegrade
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describe a retrograde urethrogram
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+ or - contrast inserted w/ a balloon-tipped catheter, film taken at end of injection
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Describe retrograde urethrogram
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+ contrast is placed into bladder (must use enough to induce urination), film is taken at voiding
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When is esophagography indicated?
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to examine esophageal function
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Describe esophagography procedure
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barium or iodine used, pt. in lateral recumbency slowly infuse contrast agent into cheek or mix into food, take film at pt swallows
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When is an upper GI study indicated?
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to evaluate stomach and small intestine
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In what situations are barium and iodine not used in an upper GI?
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don't use iodine in a dehydrated pt, don't use barium if perforation is suspected
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Describe patient prep for an upper GI?
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21-24 hr fast, enema 4 hours prior, sedation if needed
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Describe procedure for upper GI
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do survey film first, use barium or iodine, place stomach tube, induce agent into stomach
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What views are taken in an upper GI series?
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VD, DV, & rt lateral
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Describe a double contrast gastrogram
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same as upper GI except pt needs empty stomach and gas introduced right after barium - films done right away (don't wait)
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When is a barium enema contraindicated?
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when rupture/perforation is suspected
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Describe procedure for a barium enema
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survey films first, pt in lateral recumbency, lubricated enema cath inserted and balloon inflated, infuse media slowly
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What is a pneumoperitonealgram
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the injection of CO2 or nitrous into the peritoneal cavity to improve the contrast of abdominal organs
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What is a myelogram?
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induction of iodine contrast into the subarachnid space around the spinal cord
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What is a non-selective angiogram?
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injection of a bolous of iodine contrast into a vessel - film is taken at time of injection and is effective for identifying occulsions or aneurisms
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How does US work?
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Short bursts of ultra-high frequency sound waves are xmitted into patient. When they hit something they bounce back and are converted into a white dot on monitor screen.
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In US, the greater the difference in density and composition between two adjoining tissues, the ____ the echo will be.
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stronger
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In US, the stronger the echo, the ____ the white dot on the monitor screen.
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brighter
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In US, what determines the position of the white dot on the monitor screen?
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the length of time between the production of the sound burst and the return of the echo
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In US, echos from deeper tissues take ____ to return to the transducer and will be be placed as white dots ____ on the monitor screen.
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longer, lower
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In US, echos from more superficial structures tissues return ____to the transducer and will be be placed as white dots ____ on the monitor screen.
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faster, closer to the top
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What is the appearance of fluid on an US?
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Black
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What is the appearance of soft tissue on an US?
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shades of grey
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What is the appearance of bone/stone/gas on an US?
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white
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What is acoustic impendance?
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How well a substance xmits sound
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What is acoustic interface?
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the boundary between two tissues w/ different xmitting properties (causes returning echo)
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What is echogenicity?
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the ability to produce echos
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What is anechoic?
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produces no echos (no dots on screen)
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What is hypoechoic?
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Produces weak echoes (grey dots on screen)
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What is isoechoic?
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produces echoes similar to background echoes
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What is hyperechoic?
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produces intense echoes (bright white dots on screen - bones)
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What is resolution?
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The degree of image detail and quality
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One cycle per second is called a ____.
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hertz
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One million cycles/second is called a ____.
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megahertz
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Diagnostic US uses sound waves at what frequency?
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2-10 MHz (2-10 million cycles/second)
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What is attenuation?
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sound waves are attenuated or decreased as the travel through tissue
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What three thing can cause attenuation?
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absorption, reflection, and scatter
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What are three common transducer frequencies?
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3.5, 5, and 7.5 MHz
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The higher the transducer frequency, the ____ the sound wave is attenuated, but the ____ the detail.
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faster, better
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lower transducer frequency = ____ penetration and thus ____ poorer resolution
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better penetration, poorer resolution
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higher transducer frequency = ____ penetration and thus ____ poorer resolution
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lower penetration, better resolution
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US does not penetrate what three things?
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bones, stones, and air
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In US, you must have gel between transducer and skin in order to eliminate what?
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air gap
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What is an acoustic window?
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clear path for sound wave around bones or lungs to get to structure of interest
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What is acoustic shadowing useful in identifying?
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bladder stones
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What is acoustic enhancement and what is it used for?
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Concept that sound waves travel through fluid more readily thus they have higher remaining energy when they pass through an area composed of fluid. Useful in differentiating a solid tumor from an abscess.
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What is the most common display format in US?
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Real Time - produces a moving picture - can see fetal movement and heart beating
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In US, what type of display format isn't used much anymore.
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A Mode
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In US, what display format isn't used very often, produces a still life picture, and is also called "brightness mode"?
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B Mode
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In US, what display format is used w/ echocardiography, produces an "ice pick" view of the heart, and makes a line tracing of heart wall and valve action?
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M Mode
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