Curry Chapter 4 Flashcards
Acoustic enhancement
“increased echo amplitude” or “posterior through transmission” visualized posterior to a structure that does not attenuate (decrease, stop, impede, or absorb) the sound beam. considered a type of sonographic artifact
example: bright posterior through transmission can be visualized posterior to the urinary bladder
ALARA (as low as reasonably achievable)
the prudent use of diagnostic sonography dictates that the output level and exposure time to ultrasound is minimized while obtaining diagnostic data
example: the thermal index(TI) and mechanical index (MI) are components of ultrasound bioeffects that should be monitored while scanning. The TI and MI values are usually located in the upper right side of the display screen.
Anterior (ventral)
situated at or directed toward the front. a structure in front of another structure.
Example: the liver is situated anteriorly in the body. The body of the pancreas is anterior to portions of the: splenic vein; superior mesenteric artery; left renal vein; abdominal aorta; spine.
The head of the pancreas is anterior to the inferior vena cava.
Acoustic impedance
Resistance a material provides to the passage of sound waves.
example: bone portrays more acoustic impedance than tissue.
acoustic shadows
“reduced echo amplitude” or echo “drop off” posterior to a structure that attenuated (decreases, stops, impedes, or absorbs) the sound beam. Margins of the shadow are generally sharp and well-defined. considered a type of sonographic artifact.
example: black posterior shadowing can be visualized posterior to the fetal femur.
anechoic
term used to describe an echo-free appearance on a sonographic image
example: a true cyst appears anechoic
artifact
image artifacts are echo features or structures observed on ultrasound images that are unassociated with the object being imaged
example: acoustic shadows are one type of sonographic artifact
ascites
accumulation of serious fluid anywhere in the abdominopelvic cavity
example: ascites may be visualized in the posterior cul-de-sac of the abdominopelvic cavity
attenuation
decrease in the intensity of the sound beam as it passes through a structure, caused by absorption, scatter, or beam divergence
example: the density, composition, and angle of the sound beam when it strikes an object determine how much of the sound beam is attenuated
axial (short axis) (view or section)
at right angle to longitudinal sections.
example: axial views of the aorta may be seen in transverse scanning plane images. axial sections of the pancreas can be visualized in sagittal scanning plane images of the mid hypogastrium.
beam divergence
widening of the sound beam as it travels
Example: the pyramid appearance of an ultrasound image typifies bean divergence.
calculi/ “stones”
concentration of mineral salts that may accompany some disease processes.
Example: calculi are often visualized within the gallbladder as bright, movable, structures that vary in size and cast posterior shadows.
calipers (electronic)
two or more measurement cursors that can be manipulated to calibrate the distance between echoes of interest on the image
Ex: measurement calipers are used to obtain length, width, and anteroposterior measurements to provide the dimensions or total volume of a structure of interest.
color flow doppler
doppler shift info in a 2D presentaion superimposed on a real time gray scale anatomic cross-sectional image
ex: flow directions are presented as diff colors on the ultrasound display screen
complex mass
abnormal mass within the body composed of both tissue and fluid
ex: a complex mass is classified as an abnormal tissue and fluid collection within the body that disrupts the otherwise normal echo pattern of organ parenchyma
contralateral
situated on or affecting the opposite side
ex: the ovaries are contralateral organs
contrast
a comparison to show differences
ex: an ultrasound image produced a preponderance of dark and light comparative gray scale tones
coronal scanning planes
any plan parallel to the long axis of the body and perpendicular to sagittal scanning planes
ex: a coronal scanning plane image demonstrated the anatomy visualized in a lateral to medial dimension and superior to inferior dimension
- does not display anterior/ posterior
coupling agent
substance used to reduce air between the ultrasound transducer and surface of the skin
ex: gel is a typical coupling agent used in sonography
Crura of diaphragm
right and left crus or fibromuscular bands arising from the lumbar vertrebrae that insert into the central tendon of the diaphragm
ex: the crura of the diaphragm are often visualized on ultrasound images as curvilinear structures immediately adjacent to the spine. their sonographic appearance varies from bright to hypoechoic relative to adjacent structures
cystic
describes the sonographic appearance of a fluid collection within the body that does not meet the criteria to be considered a true cyst
ex: ascites is said to be cystic in nature
deep
internal, situated away from the surface
ex: the kidneys are deep structures within the body
depth of penetration
max distance the sound bean travels from the transducer through a medium
ex: the greater the distance the beam will travel through a medium. the greater the attenuation of a medium, the less the distance of travel
diffuse disease
infiltrative disease throughout an organ that disrupts the otherwise normal sonographic appearance of organ parenchyma
ex: infiltrative disease alters the normal echo pattern throughout an organ
distal
situated farthest from the point of origin
ex: the abdominal aorta is distal to the thoracic aorta
doppler (effect)
change in observed sound frequency caused by relative motion between the source of the sound or reflector and the observer.
ex: doppler is used to detect blood flow through vessels. it detects not only the presence of flow but also the direction of flow by measuring the difference in the frequency of the reflected sound compared with the transmitted sound.
echogenic
describes a structure that is able to produce echoes or echo pattern. hyperechoic, hypo, and anechoic are the terns used to quantify either an abundance or absence of echoes displayed by a structure in a sonographic image
ex: body structures are echogenic or capable or producing echoes
echopenic
few echoes
ex: the bile-filled gallbladder may appear echopenic
echo texture
describes the sonographic appearance of soft tissue structures within the body
ex: normal organ parenchyma (soft tissue) is charactized sonographyically as homogeneous or uniform in echo texture. if disrupted or changed by disease, the parenchyma typically assumes an irregular or heterogeneous echo texture or pattern. the nature of this change may be diffuse disease (infiltrative;focal) or localized disease ( a mass or multiple masses circumscribed to a specific area)
extraorgan pathology
abnormal disease process that originated outside of an organ
ex: an extrahepatic mass may be visualized originating outside of an organ causing abnormalities such as displacement of other organs and structures, obstruction of other organs or structures from view, internal invagination of organ capsules, and discontinuity of organ capsules.
focal/ multifocal change
disease process confines to isolated areas of an organ
ex: a focal area of altered echo pattern may be visualized in only a part of an organ
focal zone
the point at which the sound beam is the narrowest and the resolution is the best.
ex: different transducers have different depths where their focus or focal zone is optimal. therefore, the depth of a structure (of interest) within the body determines which transducer should be used.
gray scale
scale of achromatic colors having multiple graduations from white to black
ex: sonographic display format where echo amplitude (intensity) is recorded and presented as variations in brightness of shades of gray.