Chapters 1-4 Flashcards
What’s the basic beam profile?
transducer -> near field -> focal zone -> far field
What’s another word for near field?
Fresnel
What’s another word for far field?
Fraunhofer
Define the focal zone.
The focal zone is the region around the focus where the beam is relatively narrow.
Reflections from the focal zone create images that are more accurate than from other depths.
Depth of view
Describes the maximum distance into the body than an ultrasound system is imaging.
The markers along the edge of an image indicate depth.
Define gain.
Receiver gain increases the amplitude of the returning signals
This creates a brighter image
Define TGC.
Time Gain Compensation) adjusts gain according to depth
Can transducers change from one frequency to another?
Yes. The Transducer is capable of switching from one frequency to another by changing the frequency of the “transmitter” voltage.
What is Spatial Resolution?
Spatial resolution refers to how closely positioned two reflectors can be to one another and still be resolved as two different objects on the display
When structures are displayed as separate images we say that they are resolved
What are 3 resolutions included in spatial resolution?
axial, lateral, and slice thickness resolution
These 3 resolutions are listed from best to worst
What does image resolved mean?
objects have good resolution. aka the two objects can easily be told apart.
What are the other names of Axial resolution?
L-A-R-R-D Longitudinal Axial Range Radial Depth
Which direction is the axial resolution?
The y axis. From anterior to inferior. aka one above the other.
What are the other names of Lateral Resolution?
L-A-T-A Lateral Angular Transverse Azimuthal
What direction is lateral resolution?
x axis. From right to left. aka side by side
What is lateral resolution determined by?
Lateral resolution is determined by the beam width
A narrow beam width gives a good lateral resolution
What is Temporal resolution.?
The ability to depict the movement of structures accurately
Temporal resolution is very important in the depiction of moving objects, such as the heart
Temporal resolution is determined by the frame rate
If frame rate increases, so does the temporal resolution. Because more frames gives a better view like in tvs.
What do multiple focal zones do?
decrease temporal resolution
improve lateral resolution
increase sensitivity of the sound beam
make the overall beam thinner
Name the abdominal regions in their correct location/.
right hypochondrium, epigastrium, left hypochondrium.
right lumbar, umbilical region, left lumbar.
right iliac, hypogastrium, left iliac.
Name the abdominal quadrants correctly. And which organs are located in each of them.
right upper quandrant, left upper quandrant.
right lower quadrant, left lower quandrant.
Name body planes and directional terms.
Coronal plane. sagittal plane. transverse plane. lateral. medial. distal. proximal. superfical. deep. anterior. posterior.
Name directions of the sagittal plane on monitor.
anterior (on top) and posterior (bottom).
superior (on left) and inferior (on right).
Name directions of the transverse plane on monitor.
anterior (top) and posterior (bottom).
right (left) and left (right).
Acoustic enhancement
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.
Acoustic impedance
The resistance a material provides to the passage of sound waves.
Acousting shadows (shadowing)
“Reduced echo amplitude” or echo “drop off” posterior to a structure that attenuates (decreases, stops, impedes, or absorbs) the sound beam. Margins of the shadow are generally sharp and well defined. Considered a type of sonographic artifact.
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.
Anechoic
Term used to describe an echo-free appearance on a sonographic image.
Anterior/ventral
Situated at or directed toward the front.A structure in front of another structure.
Artifact
Image artifacts are echo features or structures observed on ultrasound images that are unassociated with the object being imaged.
Ascites
Accumulation of serous fluid anywhere in 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.
Axial
At right angles to longitudinal sections. Term used to describe the section of a structure portrayed within a scanning plane image.
Beam divergence
Widening of the sound beam as it travels.
Calipers
Two or more measurement cursors that can be manipulated to calibrate the distance between echoes of interest on the imaging screen.
Color flow Doppler
Doppler shift information in a two-dimensional presentation superimposed on a real-time gray-scale anatomic cross-sectional image.
Flow directions are presented as different colors on the ultrasound display screen.
Complex mass
Abnormal mass within the body that is composed of both tissue and fluid.
Calculi/stones
Concentration of mineral salts that may accompany some disease processes.
some disease processes.Calculi are often visualized within the gallbladder as bright, movable structures that vary in size and cast posterior shadows.
Contralateral
Situated on or affecting the opposite side.
The ovaries are contralateral organs.
Contrast
A comparison to show differences.
Coronal scanning planes
Any plane parallel to the long axis of the body and perpendicular to sagittal scanning planes.
Coupling agent
Substance used to reduce air between the ultrasound transducer and surface of the skin.
Gel is a typical coupling agent used in sonography.
Crura of diaphragm
Right and left crus or fibromuscular bands arising from the lumbar vertebrae that insert into the central tendon of the diaphragm.
Cystic
Describes the sonographic appearance of a fluid collection within the body that does not meet the criteria to be considered a true cyst.
Deep
Internal.Situated away from the surface.
Depth of penetration
Maximum distance the sound beam travels from the transducer through a medium.
Diffuse disease
Infiltrative disease throughout an organ that disrupts the otherwise normal sonographic appearance of organ parenchyma.