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116 Cards in this Set
- Front
- Back
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Ultrasounds or radiology.... Provides a good overview of the thorax and is good for evaluation of lungs, cardiac size and bone.
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Radiographs
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Ultrasounds or radiology..... not good at evaluating air-filled structures or bone.
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Ultrasounds
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Ultrasound or radiology.... Good for evaluation of bones.
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Radiology
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Ultrasound or radiology.... Good for evaluation of soft tissues e.g. tendons, muscles.
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Ultrasound
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Ultrasound or radiology..... Good for evaluation of free abdominal gas, size of liver, spleen and kidneys (small animals).
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Radiology
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Ultrasounds or radiology...... Good to use for performing a fetal count.
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Radiology
-looking for bones |
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Ultrasound or radiology..... Provides no information about the parenchymal structures.
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Radiology
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Ultrasound or radiology....... Preferred for determining the origin of an abdominal mass
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Ultrasound
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Ultrasound or radiology..... used to determine fetal viability
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Ultrasound
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Ultrasound or radiology..... used to guide fine needle aspirations/biopsy.
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Ultrasound
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Ultrasound or radiology..... Evaluation of organ parenchyma
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Ultrasound
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Ultrasound or radiology.... cannot evaluate extra-abdominal structures
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Ultrasound
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Ultrasound or radiology.... not good in evaluating air-filled structures or bones
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Ultrasound
-Cannot penetrate air |
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What are the 5 parts of an ultrasound machine?
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1) Transducer
2) Central processing unit (CPU) 3) Display 4) Keyboard 5) Storage device |
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What is the transducer?
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Probe that sends and receives the sound waves
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What is the central processing unit of an ultrasound?
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Computer that does all calculations and contains power supply for machine and transducer
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Medical ultrasound uses the principles of _______.
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Sonar
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What does the transducer (probe) of an ultrasound contain?
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Piezoelectric crystals
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What emits and receives the sounds waves in an ultrasound?
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The piezoelectric crystals in the transducer (probe) emits sound after electric charge is applied and sound is reflected
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What happens to the sound waves that are reflected back to the transducer?
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Converted into an electric signal--> grayscale on monitor
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What allows an ultrasound to identify distance, size, shape and echogenicity of objects?
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Sound propagates through a medium and produces echoes which allow us to identify these things
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True or false. Ultrasounds still utilize electromagnetic radiation.
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False, no electromagnetic radiation
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What are 4 advantages of ultrasounds?
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1) Real-time (no wait)
2) Pain-less 3) Low cost 4) Widely available |
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_______, _______ and ______ are used to describe sound waves.
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Frequency
Wavelength Velocity |
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What is the frequency? Units?
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Number of times a wave is repeated/second
-Units=Hz |
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Diagnostic ultrasounds are ____-_____ MHz.
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2-13 MHz
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What is the definition of the wavelength?
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Distance traveled through one cycle
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Higher frequency ultrasound=____ resolution, ______ penetration
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Better resolution
Lower penetration Lower frequency=lower resolution, better penetration |
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What is an example of a use for a high frequency probe?
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tumor staging
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What determines the speed with which an acoustic wave travels?
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Density and stiffness o the media
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The greater the _______, the faster the acoustic wave will travel.
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Greater the stiffness
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Do sound waves travel faster in solids or liquids/gases?
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Faster in solids
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As a sound wave travels it gets attenuated, what happens to the sound waves' intensity and amplitude?
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Intensity and amplitude decrease
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Do deep structures or superficial structures have a weaker echo?
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Deep structures
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What waves you send into the body and what comes back to the probe varies because of ______.
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Attenuation
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What is the major cause of attenuation of acoustic waves?
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Soft tissue absorption, which is the conversion from acoustic energy into heat (where can get side effects)
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What is the problem in adding a Doppler if going to do an ultrasound of a fetus?
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Adding a doppler increases the heat produced by attenuation
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What are the 4 interactions of sound waves?
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1) Absorption
2) Reflection 3) Scattering 4) Refraction |
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What is reflection? What is the angel of incidence equal to?
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Sound wave bounces back to source of echo
-Angle of incidence=angle of reflection |
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What is scattering of sound waves?
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Sound waves counter media with non-homogenous surface and a small portion of sound wave is scattered in random directions while most of it continues in its original path
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What is refraction?
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Change of direction due to change of speed
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What are the 3 ultrasound modes?
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1) B-mode= brightness mode
2) M-Mode=motion mode 3) Doppler modes |
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What is the most common mode of ultrasounds?
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B-mode
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What information does B-mode provide?
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Structural information in a 2D image
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What information does M-Mode provide?
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Capture returning echoes in only one line of the B-mode image but displays it over a time axis
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What is a Doppler ultrasound?
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Frequency of the echo is changing when the object is moving
-Higher frequency when object moves towards the probe and lower when object moves away from the probe |
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What are the 3 types of Doppler ultrasound modes?
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1) Color doppler
=Color flow ultrasound 2) Power doppler 3) Spectral doppler |
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What is color doppler?
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-Shows flow or tissue motion in a 2D image area (gives info on flowing structures)
-Direction and velocity of tissue motion or blood flow are color coded |
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How do you evaluate a color doppler key?
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Black line is considered transducer so look at black line and whatever color is on top is coming towards you and what's on bottom is going away from you
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What is Power Doppler used to detect?
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Able to detect very low flows
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True or false. Power Doppler can evaluate the flow velocity and direction of flow.
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False, color Doppler examines flow velocity or direction of flow, but power doppler is more sensitive to the presence of flow
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What is Spectral Doppler?
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Continuous and pulsed-wave form; used in cardiac studies; put a box in vessel of interest and look at flow of structure
e.g. veins will just see a uniform line, arteries will see pulse |
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Echogenicity relates to the relative _______ of a structure.
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Brightness
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What is anechoic?
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No echo within structure and appears black
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What is hypoechoic?
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If two structures are compared the darker structure is hypoechoic and the brighter structure is hyperechoic
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What do you call two structures that have the same echogenicity?
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Isoechoic
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What 3 structures of the body are the most hyperechoic (most echoic)?
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Bone, gas, organ boundaries =brightest
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What are the 2 least echoic structures in the body?
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Bile, urine (blackest)
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List structural fat & vessel walls, renal medulla, renal cortex, muscle, liver, prostate, renal sinus, liver, storage fat and spleen in the order from most echoic to least echoic.
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1) Structural fat & vessel walls
2) Renal sinus 3) Prostate 4) Spleen 5) Storage fat 6) Liver 7) Renal cortex 8) Muscle 9) renal medulla |
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What are the organ echogenicities from least to most echogenoic(5)? (what's the pneumonic)?
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Medulla (kidney)
Cortex of the kidney Liver Spleen Fat in renal Pelvix *My Cat Loves Sunny Places |
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What does the term ultrasound artifacts refer to?
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Findings seen on the ultrasound image that do not exist in reality
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What are 3 types of artifacts commonly encountered on ultrasounds?
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1) Attenuation artifacts
-Shadowing, distal enhancement, edge shadowing 2) Propagation artifacts -Revertebration, comet tail, mirror imaging 3) Miscellaneous -side lobe |
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What structures cause shadowing?
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very mineral dense structures, structures the ultrasound doesn't penetrate through so it's black behind it
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What causes distal enhancement?
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Waves are less attenuated in a fluid filled structure such as bile so structures distal to it look brighter
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What causes shadowing?
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Partial or total reflection or absorption of the sound energy
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In terms of shadowing, a weaker signal returns from behind a ______ reflector (air) or sound breaking structure (___, ___).
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Strong reflector
(stone, bone) |
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What is distal enhancement?
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The area behind an echo-weak or echo-free structure appears brighter (more echogenic) than its surrounding structures
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Why does distal enhancement occur?
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Because neighboring signal had to pass through more attenuating structures and return w/ weaker echoes
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What is edge shadowing?
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A thin acoustic shadow that appears behind edges of cystic structures
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What causes edge shadowing?
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Sound waves encountering a cystic wall or a curved surface at a tangential angle are scattered and refracted, leading to energy loss and the formation of a shadow
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The marker is always placed on the _____ side of the image.
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Right side or cranial
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What are the 3 attenuation artifacts?
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Shadowing
Distal enhancement Edge shadowing |
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What are the 3 propagation artifacts?
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1) Reverberation
2) Comet tail artifact 3) Mirror imaging |
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When does reverberation occur? What is it?
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When sound encounters two highly reflective layers. The sound is bounced back and forth b/w the 2 layers before traveling back
-Probe will detect a prolonged traveling time and assume a longer traveling distance and display additional "reverberated" images on a deeper tissue layer |
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In what part of the body is reverberation really common?
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Lungs
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Comet tail is similar to what other artifact?
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Reverberation
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What is a comet tail?
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Produced by the front and back of a very strong reflector (air bubble, BB or gun pellet)
Reverberations are spread very narrowly and blend into a small bnad |
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Where do mirror images occur (in what structures)?
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In a structure that is located close to a highly reflective interface (Such as the diaphragm)
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What causes a mirror image to be produced?
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The strong reflector causes additional sound waves to towards the nieghboring anatomy, from where they are bounced back towards the strong reflector and return to the transducer, these sound waves have a longer travel time and are perceived as an additional anatomic site==? image is duplicatedon the other side of the strong reflector
e.g. duplication of liver on other side of diaphragm |
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Side lobe artifacts are caused by low energy "side lobes' of the________.
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Main ultrasound beam
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What is a side lobe artifact?
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When echo from side lobe beam becomes strong enough and returns to the receiver, it is "assigned" to the main beam and displayed at a false location
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Where are side lobe artifacts usually seen? How do they appear?
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In hypoechoic or anechoic structures and appear as bright and rounded lines
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What are the 6 structures of the liver can be evaluated using ultrasonagraphy?
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1) Size & shape
2) Echogenicity -Homogenous 3) Vessels 4) Bile ducts 5) Surface 6) Gallbladder |
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The liver is less echoic than the ______ or _____ and is isoechoic or hyperechoic to the ________.
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Hypoechoic: spleen & falciform fat
Isoechoic or hyperechoic: cortex of the adrenal gland |
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What 3 properties of the spleen can be evaluated using an ultrasound?
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1) Size & shape
2) Echogenicity -Homogenous 3) Surface |
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The spleen is hyperechoic compared to the _____ and ______ and less echogenic than the fat of the _______.
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Hyperechoic: liver parenchyma & cortex of kidney
Hypoechoic: fat in renal pelvis |
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What layers can be seen in the wall of the stomach using an ultrasound? How thick is a normal stomach wall?
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Normally all 5 layers can be seen
-Thickness: 3-5 mm |
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How many contractions per minute does a normal stomach have?
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4-5 contractions /minute
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What part of the small intestine is most consistent in its position? Where is it located?
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Duodenum- starts at the pylorus and "runs" along the right abdominal wall until the tuber coxae
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Which of the 5 layers of the small intestine are hypoechoic (black)?
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M & M:
Mucosa & muscularis |
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How many contractions per minute is normal in the small intestine?
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Duodenum: 4-5 contractions (same as stomach)
Rest of SI: 2-3 contractions/minute |
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How thick is the small intestine normally?
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2-3 mm, duodenum wall up to 5 mm thick
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How many layers comprise the wall of the colon? How thick is the wall of the colon?
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3 layers
1-2 mm thick |
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What are the 5 layers of the stomach & small intestine (start in lumen & go out)?
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1) Mucosa
2) Submucosa 3) Muscularis -Mucosa> muscularis 4) Subserosa 5) Serosa |
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What shape is the pancreas on an ultrasound?
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V shaped: right limb & left limb
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Where is the right limb of the pancreas located?
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Medial and slightly dorsal of the descending duodenum
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Where is the left limb of the pancreas located?
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In the mesenterym, "runs" from right to left in the cranial abdomen along the creater curvature of the stomach
-Ends in the area of the hilus of the spleen or the cranial pole of the left kidney |
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The pancreas is isoechoic with __________, isoechoic or minimally hyperechoic with the ______ and less echogenoic than ______
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Isoechoic with surrounding mesentery, isoechoic or minimally hyperechoic w/ liver, less echogneic (hypoechoic) to spleen.
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What is the size and shape of a kidney as seen w/ an ultrasound?
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Bean shaped
Symmetric like "cut open tomato" |
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Is the cortex or medulla of the kidney hyperechoic?
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Cortex is hyperechoic compared to medulla
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What is the shape of the left and right adrenal glands in a dog? cats?
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Dogs:
-left=bean shaped -Right= coma shaped Cat: more ovoid shaped |
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Is the cortex or medulla of the adrenal glands hyperechoic?
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Medulla is hyperechoic to cortex (Opposite of kidney)
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How does the content of the urinary bladder appear?
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Anechoic-black
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Why should the bladder be distended when ultrasounds are performed?
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Because an empty bladder has thicker walls compared to the thin walls of a distended bladder
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How does an ultrasound of cystitis appear?
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Hyperechoic on the outside of the bladder
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A normal uterus and ovaries are ______on an ultrasound.
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Small
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How should normal prostate parenchyma appear on an ultrasound?
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Homogenous
Hypoechoic |
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What are 2 musculoskeletal injuries that are detected by ultrasounds?
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Tendon injuries
Muscle injuries |
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What are 4 risks of performing an ultrasound guided fine needle aspirate and biopsy?
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1) Hemorrhage
2) Pneumothorax w/ pulmonary masses 3) Seeding of tumor cells -Especially 4) Infection |
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What is the preferred technique for performing an ultrasound-guided core biopsy?
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Biopsy "gun"
14-20 g Insert through very small skin incision |
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Why are biopsy guns the preferred biopsy technique with ultrasounds?
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Get a more representative sample
-Tissue not just cells |
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What is the risk of doing a biopsy gun technique?
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Has a much higher risk of bleeding
-So usually start with fine needle aspirate and then biopsy if needed |
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In the _____, biopsies are often needed to get an answer, if no diffuse changes are present.
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Kidneys
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Why are biopsy guns the preferred biopsy technique with ultrasounds?
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Get a more representative sample
-Tissue not just cells |
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What is the risk of doing a biopsy gun technique?
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Has a much higher risk of bleeding
-So usually start with fine needle aspirate and then biopsy if needed |
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In the _____, biopsies are often needed to get an answer, if no diffuse changes are present.
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Kidneys
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