Echogenicity
a measure of acoustic reflection due to the ability of a tissue to reflect an ultrasound wave
echogenic
describes an organ or tissue that is capable of producing echoes by reflecting the acoustic beam
Hypoechoic
portions of an image that are not as bright as surrounding tissues, or tissues that appear less bright than normal
Hyperechoic
tissue that reflects more sound back to the transducer than the surrounding tissues; appears bright
Isoechoic
tissue that has the same ultrasonic appearance as that of the surrounding tissue
Anechoic
without echoes, or black
cyst
well defined, round, fluid filled structure with few to no internal echos with posterior enhancements
cysitic
a term used to describe a fluid-filled structure
Solid
contains echoes, grey echoes
complex
has both cystic and solid components
fluid-filled level
Interface between two fluids with different acoustic characteristics
Echotexture
characteristic pattern of echoes within tissue parenchyma, smooth or coarse
homogeneous
uniform composition, the liver appears this way
heterogeneous
non-uniform composition, Kidney is the only organ that we look at that is this way.
gain
a measure of the strength of the echoes through the image. Controls the degree of echo amplification (brightness) Measured in dB. Too much gain = artifacts in fluid-filled structures. Too little gain = negates real echo information. ALARA
Time Gain Compensation (TGC)
control that compensates for attenuation (loss of sound beam) as it passes through tissue. Slide pods AKA pots or sliders. Used together with gain for a uniform image.
Specular reflector
reflection from a smooth surface at right angles to beams. Diaphragm + bone
acoustic enhancement
area posterior to a cystic structure that appears brighter than surrounding tissue. through transmission
noise
artifactual echoes that are resulting from too much gain rather than true anatomy
reverberation
multiple echoes displayed at increasing depths due to bouncing of the sound beam between two or more strong interfaces
ring down
an extreme form of reverberation associated with air/ gas and appears as a bright linear streak or series of parallel bands
shadowing
failure of a sound beam to pass through a structure. clean vs. dirty shadows
smooth
uniform smooth appearance of an organ
Abdominal regions - RT + LT Hypochondriac
top row Rt + Lt sides of tic tac toe
Abdominal regions - Epigastric
top row center of tic tac toe
Abdominal regions - Rt + LT flanks
Middle row RT + LT of tic tac toe
Abdominal regions - UMBILICAL
middle row, center of tic tac toe
Abdominal regions - RT + LT groin
bottom row RT + LT of tic tac toe
Abdominal regions - Hypogastric
bottom row, center of tic tac toe
unilateral
pertaining to one side. ex) L leg
bilateral
both sides. ex) both legs
Ipsilateral
on the same side of the body. ex) RT arm + leg
Contralateral
on the opposite side of the body. ex) RT arm + LT leg
Amplitude
measured in decibles (dB). Measures how quiet or loud the echo strength is.
Frequency
pitch of the sound wave. It asks how many cycles are occurring in 1 sec.
Pulse repetition rate
The number of times per second that a transmit-receive cycle occurs
Greyscale
shows echoes in varying levels of grayness, depending on the strength of the interface
beam angle interface
The strength of the returning echo is related to the angle at which the beam strikes the acoustic interface. Perpendicular = stronger returning echoes = better image
Attenuation
the progressive weakening of the sound beam as it travels through a medium. prevents you from seeing distal portions of structures.
Resolution
the ability to distinguish two structures as two adjacent but different structures
beam profile
sound beams vary in shape and resolution. can be focused. the best lateral resolution is located in the area of the focal zone.
Near zone
closer to the transducer, fresnel zone.
the focal zone
beam is narrowed to improve the lateral resolution
far zone
farthest from the transducer, Fraunhofer zone. Lateral resolution is diminished bc it is beyond the area of focusing.
A-Mode
amplitude Modulation, most basic form of diagnostic U/S + is no longer used. single beam analyzed, it could only show if something were present
B-Mode
dot's of varying brightness. strong echo = bright dots. weak echos = less brightness. echo depth is determined by the time it takes the echo to return to the transducer and display on the monitor. 2-D scan
M-Mode
motion mode, used in echocardiography, OB fetal heart rate + movement of the diaphragm.
real time B-Mode
images can be taken in sequence. constant feedback with rapid, 30 refreshes / sec. extended structures can be followed, observation of movement, portable.
Frame Rate
# of times that our image is refreshed in real-time display. To improve FR = minimum # FZ, decrease width + depth
Real-time imaging
all modern U/S units. Consists of a scan converter and transducers.
scan converter
Portions of the imaging system in which the echoes are converted to a television image: digital scan converters store the image so that it can be pre- + post- processed.
transducer crystal
Piezoelectric crystal made of zirconate titanate (PZT). convert the electric voltage into acoustic energy upon transmission and acoustic energy to electrical energy upon reception.
matching layers
lie in front of the transducer element. provides a step-down layer between the transducer and the skin. Aids in sound beam transmission bus some impedance occurs here.
damping material
attached to the back of transducer element to decrease secondary reverberations of the crystal with returning signals. increases axial resolution.
Transducer Case
provides a housing for the crystal, damping material layer, and insulation from interference from electrical noise
electronic cable
bundle of wires to excite the transducer and receive the returned electrical impulses
mechanical transducers
crystal is physically moved to provide steering for the beam. Provide a sector image with fixed focus. 3D + 4D transducers
Oscillating transducer
The motor drives the transducer element back and forth to produce a sector image. No Longer Used.
Electronically Steered Systems
Multiple PZT elements used, each has its own electrical supply. Steering and focusing
Electronically Steered Systems: Linear Sequenced Arrays
multiple elements mounted on a straight or curved bar. Groups of elements are electronically pulsed at once to act as a single larger element. Pulsing occurs sequentially, moving the sound beam from end to end.
Electronically Steered Systems: Phased Array
multiple transducer elements mounted compactly in a line. All elements pulsed w/ small-time delay. image is sector/vector format. useful for intercostal + cardiac. Small footprint
Multi-D Array Transducers
multiple rows of elements to form a matrix of crystals. Crystals are pulsed in sequence for improved resolution and a very thin slice thickness.
Specialized U/S Transducers
small parts, rectal, biopsy, doppler probes, endocavity, transesophageal, intraluminal/ intracardiac
Transducer Image Format: Linear Array
rectangular footprint. Superficial structures, excellent resolution. Used for thyroid, testicles, breast, vascular.
Transducer Image Format: Curved
Large field of view. Convex footprint, good resolution. Used for abdomen + OB scans (transabdominal) we use these the most
Transducer Image Format: Sector
small wedge footprint, deeper penetration, resolution suffers
Transducer Image Format: Vector
small trapezoidal footprint, deeper penetration, resolution suffers. Used for cardiac + neonatal brain
Transducer Image Format: 3D Imaging
Multiplanar rendering of normal structures and pathology. Used in OB scans and to check IUD placement.
Transducer Image Format: 4D Imaging
Real-time imaging of a 3D image. Mostly for OB.
Elastography
A sonographic technique employed to evaluate a mass based on its stiffness. Two types: Compression + Shear- Wave
Compression Elastography
Qualitative stiffness through colors. Manual compression of the tissue. Used in breast imaging.
Shear-Wave Elastography
qualitative + quantitative stiffness of an organ. Uses an electronic push pulse to provide compression of tissue. Used in liver imagine. Qualitative = color hues ; Quantitative = numbers.
Dynamic Range
range of intensities from the largest to the smallest echo a system can display. Usually do not adjust this setting
Edge enhancement
alters the edges of the image pixels to accentuate the transition b/t areas of different echogenicitys. pre- processing = before the image is frozen. Usually do not adjust this setting.
frequency selection
allows the user to choose b/t different sending frequencies of the transducer (transducer frequency)
pulse repetition frequency
# of times / sec that a transmit-receive cycle occures. (PRF / Velocity / Scale)
Maps
Changing maps changes echo intensities. May allow for better pathology evaluation. Post-processing = after image is frozen. Can alter image aesthetics by placing more or less emphasis on echo intensities.
Persistence
Frame average function. Creates a smoother image. What we need to get through this next year and a half :)
Harmonics
Displays images at twice the transmitted frequency. Reduces artifacts. Used w/ fluid filled things such as the gallbladder.
Cine Loop
System memory stores the most recent sequence of imaging frames. Useful in pediatric scanning or if the patient cannot hold their breath or keep still.
Auto Optimization
Personal preference button
Focal Zones
enhances the resolution of an area in the image
Wall Filter
the operator control that eliminates low-frequency, high-amplitude doppler signals caused by wall or valve motion; also called high-pass filter
Calipers
markers for measuring
Zoom ( read zoom)
Magnifies the image by increasing the pixel size. Post-processing feature. Degraded image quality.
RES (Write Zoom)
Magnifies the image w/out increasing pixel size. Pre-processing feature. The box is placed on the screen + the areas w/in the box is expanded. Image is a true magnification.
RLD
patient lying on their right side to image spleen or left Kidney. They are facing you
LLD
patient lying on their left side. Image GB, liver + RT kidney. also use this position for pregnant patients that feel faint.
Trendelenburg position
A position in which the patient's feet and legs are higher than the head
Fowler's position
Semi-sitting position; the head of the bed is raised between 45 and 60 degrees. legs are also raised / bent
Semi-Fowler's Position
The head of the bed is raised 30 degrees; or the head of the bed is raised 30 degrees and the knee portion is raised 15 degrees
Image Labeling Standards
Permanent medical-legal record. Clear + concise. Name of facilityName of PtSonographer initialsDate + time of examScan planeOrgan being evaluatedPatient position (only if not supine)Cine loops sweep direction LMP for pelvic + OBlabel pathology that is distorting the anatomy
scanning techniques
beam should always be as perpendicular as possible to the structure. Scan through the best acoustic window possible. For something to be real, it must be real in all three planes. ULTRASOUND IS TOTALLY OPERATOR DEPENDENT: YOU CAN MAKE THINGS DISAPPEAR OR SHOW UP W/OUT KNOWING IT!!!!!!!
Transducer Selection
Always start with the highest frequency and go down as needed. High frequency = better resolution but limited penetration. Low frequency = good penetration, bad resolution.
Curved linear array transducer (MHz)
2.5 - 7.5 MHz
Linear array transducer (MHz)
7-15 MHz
Sector/Vector Transducer (MHz)
2.5 - 5 MHz
endovaginal / transvaginal exam
no full bladder. better resolution of pelvic organs, especially endometrium + cervix. Limited field of view, especially if the patient has fibroids. Invasive. For scanning GYN, early OB, cervix measurement of OB 2/3
Color Doppler
For scanning blood vessels, organ vascularity, the direction of blood flow, transplants and renal stones. Red + blue is dependent on the map and direction of blood flow (NOT vein or artery)
Work Related Musculoskeletal Disorders (WRMSD)
Injuries resulting in restricted work or time away from work or involving symptoms that last for 7 days or more.Include muscles, tendons + joints. Caused by or aggravated by workplace activities.
What % of workplace illnesses are caused by WRMSD?
60%
What % of sonographers in N. America have some form WRMSD?
93% since Covid, 80% prior. 20% of sonographers will have a career ending injury.
Risk Factors associated w/ WRMSD: Biomechanical
awkward scanning postures, always maintain a neutral position. Excessive force used in the exam + workplace design (such as chairs not close enough to bed)