Ultrasound
Michael Baram
Objectives
• Basic science
• Terminology
• Examples
– Movies
• What we should and should not be doing
Disclosures
• Becoming more of a techy.
• I have lost my touch for subclavians
• I tried to trade my kids in for a machine
(It did not work)
Anatomy of a wave
• Velocity = wavelength x frequency
• High frequency wave travel more linear and
reflected easier
Velocity through material
Medium
Speed (m/s)
Blood
1566
Brain
1505-1612
Fat
1446
Kidney
1567
Liver
1556
Muscle
1542-1656
Bone
2070-5350
Water
1480
Air
333
Brass
4430
•
Velocity of a
wave is a
constant
through a given
substance
(at a constant temperature)
•
Assumption
made all
velocity about
1540 m/s
How waves are made
US- the perfect child
Attenuation
Reflection of Beam
Partial reflection of a sound beam occurs at a
tissue interface.
Breast Mass or Cyst?
Different Waves have different
degrees of attenuation
Low vs High Frequency
4 MHz
7 MHz
Reasons for attenuation
GAIN
Shadowing
• The lateral edge shadow is a thin acoustic
shadow that appears behind edges of
cystic structures.
Shadowing
• artifact is similar to reverberation
Terminology
Image Interpretation:
• Anechoic / Echolucent - Complete absence of
returning sound waves, area is black.
• Hypoechoic - Structure has very few echoes
and appears darker than surrounding tissue.
• Hyperechoic / Echogenic - Opposite of
hypoechoic, structure appears brighter than
surrounding tissue.
Terminology
Image Acquisition / Probe Positions:
•
Transverse Plane - Also known as an axial
plane or cross section, separates the superior
from the inferior, or, the head from the feet.
•
Sagittal Plane - Oriented perpendicular to the
ground, separating left from right. The
"midsagittal plane" is a sagittal plane that is
exactly in the middle of the body.
•
Coronal Plane - Also known as the frontal
plane, separates the anterior from the posterior
or the front from the back.
•
Oblique Plane - The probe is oriented neither
parallel to, nor at right angles from, coronal,
sagittal or transverse planes.
•
Longitudinal Plane - The longitudinal plane is
perpendicular to the transverse plane an can be
either the coronal plane or sagittal plane.
Probe Types
• http://www.youtube.com/watch?v=fntJ7GLj
CSU
• http://www.youtube.com/watch?v=VF_OG
TSdSlo&feature=channel
• http://www.youtube.com/watch?v=Sb1bM8
MnpRk&feature=channel
• http://www.youtube.com/watch?v=XpN1R7
A0r_0&feature=channel
What we Should and Should Not DO
Thank you
• Any questions
Fast Exam
• Subxiphoid
bladder
• http://folk.ntnu.no/stoylen/strainrate/Ultras
ound/
• http://www.sonoguide.com/physics.html