Ultrasound Physics (SPI) Review/Study

Ultrasound Physics (SPI) Review/Study
Meaning of Anechoic? Correct Answer: Dark, less echos.

Meaning of Echogenic? Correct Answer: Full of echoes.

Meaning of Hyperechoic? Correct Answer: More echoes than adjacent tissue.

Meaning of Hypoechoic? Correct Answer: Less Echoes than adjacent tissue.

Meaning of Isoechoic? Correct Answer: Similar/same echoes than adjacent tissue.

Meaning of Homogenous? Correct Answer: Uniform Texture. (smooth)

Meaning of Heterogenous? Correct Answer: Different levels of echogenicity.

Definition of Wavelength? Correct Answer: The length of one cycle.
-Denoted by (Lamda)

Unit for Wavelength? Correct Answer: m, cm, mm

Definition of Propagation Speed? Correct Answer: The speed at which sound
travels through a medium

Unit for Propagation Speed? Correct Answer: m/s or mm/microseconds

Propagation Speed depends on? Correct Answer: Density, Stiffness.

Definition of Density? Correct Answer: Concentration of matter.
-Inversely related to prop speed.

Definition of Stiffness aka "Bulk Modulus"? Correct Answer: The resistance of a
medium to compression.
-Stiffness is directly proportional to speed.

What are the two types of Ultrasound Waves? Correct Answer: 1.)
Electromagnetic - Wave travels through a vacuum.
2.) Mechanical - Wave must travel through a medium.

,What are two kinds of Mechanical Waves? Correct Answer: A.) Transverse
B.) Longitudinal

Ultrasound images are made up of typically how many scan lines? Correct
Answer: 128 - 256 scan lines.
(more the better resolution)

Scanning format for Sector (shape)? Correct Answer: Pie Shaped, Scan lines
originate from the same location and spread out as they travel.
.
/\
/\

Scanning format for Modified Sector? Correct Answer: Scan lines originate from
different points, but close together.
///\\\
/// \\\

Scanning format for Linear? Correct Answer: Scan lines originate from different
points and travel parallel to each other. |||||||
|||||||

Definition of PRF? Correct Answer: -Pulse Repetition Frequency
-The number of cycles per second. (including listening time)

Units for PRF? Correct Answer: Hz, kHz, MHz

Formula for PRF? Correct Answer: PRP=__1__
PRF

Definition of PRP? Correct Answer: -Pulsed Repetition Period
-The time from the beginning of one pulse to the beginning of the next pulse.

Units for PRP? Correct Answer: s, ms, microseconds

Formula for PRP? Correct Answer: PRP=__1__
PRF

Definition of Pulse Duration? Correct Answer: The time the pulse is on.

, Unit for Pulse Duration? Correct Answer: Microseconds

Formula for Pulse Duration? Correct Answer: PD = n x T

Definition of SPL? Correct Answer: -Spatial Pulse Length
-The length of one pulse

Unit for SPL? Correct Answer: mm

Formula for SPL? Correct Answer: SPL = n x (lamda) aka Wavelength

Definition of Duty Factor? Correct Answer: The percentage of time the pulse is on
-Unitless (just a number)
-For continuous wave, duty factor = 100%
-For pulsed wave, Duty Factor is less than 1%

Formula for Duty Factor? Correct Answer: DF = __PD__
PRP

Definition for Bandwidth? Correct Answer: The range of frequencies found in a
pulse.
-The shorter the pulse, more frequencies.

Definition for Fractional Bandwidth? Correct Answer: Describes how large BW is
compared to frequency
-Unitless

Formula for Fractional Bandwidth? Correct Answer: FBW = __BW__ (BW =
bandwidth)
Fo (Fo = Operating Frequency)

Definition for Quality Factor? Correct Answer: Way to rate a transducer, Quality
of the transducer.
-The lower the QF, the better transducer.

Formula for Quality Factor? Correct Answer: QF = __Fo__
BW

Definition of Power? Correct Answer: The rate that work is performed.
-The rate of energy transfer