bym504e-mk-basics of ultrasound imaging
TRANSCRIPT
![Page 1: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/1.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 1
Basics of Ultrasound Imaging
April 2014
Department of Electronics & Communications Engineering,
Istanbul Technical University, Istanbul, Turkey
Mustafa Karaman, Ph.D
![Page 2: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/2.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 2
Ultrasound B-Scan Image: Liver
![Page 3: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/3.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 3
Pulse-Echo Ultrasonic Imaging System
![Page 4: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/4.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 4
Ultrasonic Imaging
• Tissue-wave interaction
• Transducer design
• Analog and digital electronic design
• Array signal processing (beamforming)
• Signal and image processing
![Page 5: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/5.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 5
Acoustic Applications
– Medical Imaging (non-invasive diagnosis)
– Nondestructive testing (NDT)
– Underwater acoustics (sonar)
![Page 6: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/6.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 6
Medical Imaging
– non-invasive observation of internal structures
of human body
Based on interaction between tissue &
energy (x-rays, electric fields, ultrasound, etc.)
Different forms of energy/radiation
imaging of different characteristics of tissue
![Page 7: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/7.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 7
Medical Ultrasound
– represents mechanical properties of tissue
– has no harmful biological side effect
– allows real-time imaging
– offers small-size, low-cost systems
complementary diagnostic tool
+ (will) provide real-time 3D imaging
![Page 8: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/8.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 8
Medical Ultrasound Waves
– Longitudinal waves: 2-15 MHz
– Transverse waves
» high attenuation in tissue
not used
![Page 9: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/9.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 9
![Page 10: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/10.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 10
![Page 11: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/11.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 11
Ultrasound Parameters
water
fat
bone
liver
kidney
muscle
soft tissue
Speed
(m/s)
1480
1440
4080
1550
1560
1590
1540
Attenuation
(dB / MHz cm)
0.0025
0.56
12.0
0.95
1.1
1.8
0.81
Impedance
1.48
1.36
7.80
1.66
1.63
1.71
1.62
)/10( 26 smkg
![Page 12: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/12.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 12
Ultrasound Parameters
![Page 13: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/13.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 13
Frequency & Wavelength
f
c
In soft tissue: C = 1540 m/s
f
(MHz) (mm)
3.0 0.51
5.0 0.31
![Page 14: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/14.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 14
Reflection
2
12
122
ZZ
ZZPower reflection coefficient:
Reflection between X and Soft tissue Z = 1.62
X 2
water + 0.452 0.020
fat + 0.087 0.008
bone - 0.656 0.430
liver - 0.003 9.6e-6
![Page 15: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/15.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 15
![Page 16: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/16.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
scattering
16
![Page 17: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/17.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 17
Reflection (Pulse-echo) & Transmission Modes
TX
Mode
(t>r/c)
![Page 18: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/18.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 18
A Sample Pulse-echo Signal
s(t)
S(w)
3.5Mhz, 40%BW
![Page 19: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/19.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 19
Attenuation in Pulse-Echo
ReII 2
0
F loss
(MHz) (dB/cm) (dB)
3.5 2.8 112
5.0 4.0 160
R
II 0
Medium Attenuation: Diffraction Attenuation:
![Page 20: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/20.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 20
Attenuation TGC
• Attenuation: compensated by TGC amplifier
• Gain: Operator controlled at discrete
range segments
range
gain
![Page 21: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/21.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 21
TGC Applied to B-Scan Image
![Page 22: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/22.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 22
Pulse-Echo Ultrasonic Imaging System
![Page 23: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/23.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
Transducers
23
PZT: Lead Zirconate Titanate
![Page 24: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/24.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
PZT: Lead Zirconate Titanate
24
ZPZT~30x105 g/cm2s ZSKIN=~1.7x105 g/cm2s
![Page 25: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/25.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
CMUT
25
vout
Vdc
~ vac
Generated Acoustic Wave
Incident Acoustic Wave
![Page 26: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/26.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
Trasnsducer Bandwidth
26
![Page 27: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/27.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
Trasnsducer Bandwidth
27
![Page 28: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/28.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 28
Beamforming
• Perhaps the most important building block.
• Probably the most expensive building block.
– 30 - 50% of parts & labor of a scanner
• Forming transmit/receive beams
Scan image plane (reconstruct image).
This slide is from K. Thomenius’ presentation.
![Page 29: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/29.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 29
![Page 30: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/30.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 30
![Page 31: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/31.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
Focusing
31
![Page 32: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/32.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
steering
32
![Page 33: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/33.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 33
Scan (Beam) Lines
![Page 34: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/34.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 34
Beamforming = steering + focusing
![Page 35: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/35.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 35
Tra
ns
du
ce
rs &
Sc
an
Fo
rma
ts
Transducer
Array
Active Subarray
Scan Line
Beam
Transducer Array = Active Subarray
Scan Line
Beam
Transducer
Array
Active
Subarray
Sc
an
Lin
e
Beam
Linear Array Curvi-Linear Array Phased Array
![Page 36: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/36.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 36
![Page 37: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/37.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 37
End of Session-1
![Page 38: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/38.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 38
Basics of Ultrasound Imaging
Session 2
![Page 39: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/39.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 39
Transducer
Array
Active Subarray
Scan Line
Beam
Transducer Array = Active Subarray
Scan Line
Beam
Transducer
Array
Active
Subarray
Sc
an
Lin
e
Beam
Linear Array Curvi-Linear Array Phased Array
Recall From Session-1:
Transducers & Scan Formats
![Page 40: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/40.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 40
Recall From Session-1: Beamforming
![Page 41: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/41.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 41
PSF
• Point Spread Function
– Image of a point reflector (target)
• Also called LSF (line spread function)
– 2D cross-sectional image of line reflector (target)
• Represents the spatial impulse response of the (linear) imaging system.
• Used to characterize
– transducer response (radiation pattern, beam pattern)
– the image quality of the system.
![Page 42: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/42.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 42
r
(r,)
D/2x
dx
Observation
point
Geometry for driving PSF
-D/2
Excitation Pulse: p(t)
Aperture
![Page 43: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/43.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 43
PSF
( / )
Signal at the observation point:
( / )( , ) cos
Assume paraxial case: cos 1 &
1( , ) ( / )
For CW excitation: ( )
( , )
D
D
jwt
wj
jw t c jwt c
D D
p t cs t dx
r
s t p t r c dxr
p t e
s t e dx e e dx
![Page 44: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/44.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 44
PSF
2
( , )( , ) /
wj
jwt jwtcjwt
D
wjc
D
j
D
s th w e e dx e
e
e dx
e dx
Temporal frequency response
![Page 45: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/45.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 45
Near & Far Fields
2 2
2
2
2
2 sin
21 sin
[1 ( ) ( ) ...]
r x rx
x xr
r r
r O x O x
2
2
[1 ( ) ( )] Near-Field (Fresnel)
/ Far-Field (Fraunhofer)
[1 ( )]
sin
r O x O x
r D
r O x
r x
Distance from source point to observation point:
r
(r,)
x
dxAperture
![Page 46: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/46.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 46
One-Way PSF
2
22 / sin
2 / sin
( , )
(sin , )
(sin ) ( )
{ ( )}
sin / sin
/ sin
j
D
j r j x
D
j x
D
D
h w e dx
h w e e dx
h a x e dx
F a x
D
(r,)
dx
Aperture
Function
aD(x)
![Page 47: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/47.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 47
(sin ) (sin )t rh h
One-Way (Tx & Rx) PSF
• Transmit and receive responses of an
aperture are identical.
• Transmit and receive beam patterns (PSFs)
of a transducer are identical.
![Page 48: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/48.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 48
3dB width
main lobe
side lobes
1/ 2
PSF for D=16sin(8 sin )
(sin )0.5 sin
h
Sin
![Page 49: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/49.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 49
Aperture & Sampled Aperture (Array)
d
(r,
r
1 2 3 N
Continious
Aperture
Function
Sampled
Aperture
Function
d
![Page 50: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/50.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 50
PSF of Sampled Aperture (Array)
1
sin( sin )2
(sin ) exp( sin )
sin( sin )
N
n
Ndh j nd
d
• Note that: It is a periodic sinc()-like function with
a period of sin=2/d.
– Sampling in one FT domain corresponds to periodicity
in the other FT domain.
• This results in repeated main lobes, so called
grating lobes.
• To avoid grating lobes, choose d/2
![Page 51: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/51.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 51
Array PSF with Grating Lobes
main lobe 3dB beam width
first side lobe
side lobes
Grating lobe grating lobe
![Page 52: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/52.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 52
Two-Way PSF
2
(sin ) (sin ) (sin )
sin( sin )(sin ) (sin )
sin( sin )
sin( sin )(sin )
sin( sin )
t r
t r
TR
h h h
Ndh h
d
Ndh
d
![Page 53: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/53.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 53
sin 0.5 16 sin(sin )
sin 0.5 sinh
One-Way PSF
![Page 54: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/54.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 54
Two-Way PSF
![Page 55: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/55.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 55
Two-Way Pulsed PSFs
R: 1D 2D 3D 4D 5D 6D 7D
arr
ay (
N=
16
, d
=/2
)
-0.5
0.0
+0.5
![Page 56: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/56.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 56
Mesh Plot of Two-Way PSFs
1D
2D
3D
4D
5D
6D
7D
![Page 57: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/57.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 57
Effective Aperture
)(sin)(sin
)}()({
)}({)(sin
)()()(
rt
rt
e
rte
hh
xaxaF
xaFh
xaxaxa
![Page 58: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/58.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 58
Aperture Apodization
Array Channels
![Page 59: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/59.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 59
Apodized PSF
)(sin)(sin
]}[][{)(sin
hW
nanwFha
![Page 60: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/60.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 60
Effect of Apodization on PSF
Xtr & Rcv Hamming Window
Xtr & Rcv Uniform Window
![Page 61: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/61.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 61
Depth of Focal Zone
focal point
depth of focal zone
2
2
88 nofD
rr
![Page 62: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/62.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 62
F/number Apodization
RangeD 2D
f/number = Rfocal / Deffective, Deffective= D * cos
• Used for improved focal zone.
![Page 63: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/63.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD
f/number apodization
63
![Page 64: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/64.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 64
Effective Aperture Size
r
(r,)
D
steering angle
focal point
D cos
effective aperture
![Page 65: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/65.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 65
Aperture Apodization
• increases depth of focal zone
•suppresses side lobes
• reduces point resolution
(increases main lobe width)
• reduces T/R power (SNR)
![Page 66: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/66.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 66
Pulse-Echo Ultrasound Imaging System
![Page 67: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/67.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 67
Output Signal of Beamformer
(Beamformed A-scan)
![Page 68: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/68.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 68
Beamformer Output
rN
n
nn crttptAts1
)/)(()()(
t rN
k
N
n
knnk crtttptAtAts1 1
)/2)()(()()()(
Receive Beamforming:
T/R Beamforming (synthetic):
![Page 69: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/69.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 69
Wavefronts With/out Focusing
Row-1: No focusing, Row-2: Xtr focusing, Row-3: Xtr & Rcv focusing
(N=64)
![Page 70: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/70.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 70
End of Session-2
![Page 71: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/71.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 71
Basics of Ultrasound Imaging
Session 3
![Page 72: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/72.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 72
Sector Scan
![Page 73: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/73.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 73
Scan-Conversion
![Page 74: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/74.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 74
Scan-Conversion
/)(
/)(
/)(
121
1212
1211
CCCC
rdBBBC
rdAAAC
![Page 75: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/75.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 75
Scan-Conversion
sin
Ran
ge (r)
x
y
![Page 76: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/76.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 76
Logarithmic Compression
• To view regions with different contrast levels on the same display range
a = 10db_floor/20; % a=0.01 for db_floor=-40;
x = x / xmax;
if x()<a then x() = a
y = 20 log10(x)
• 40 dB < dB_floor < 60 dB
![Page 77: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/77.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 77
Image Resolution
• Axial (range) resolution
• Lateral (azimuth) resolution
• Point resolution
•Contrast resolution
![Page 78: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/78.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 78
Aixal & Lateral Resolution
R: 1D 2D 3D 4D 5D 6D 7D
arr
ay (
N=
16
, d
=/2
)
-0.5
0.0
+0.5
![Page 79: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/79.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 79
Resolution of B-Scan Image
axia
llateral
![Page 80: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/80.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 80
Axial & Lateral Resolution
• Axial (Range) Resolution
pulse shape
pulse width
Xducer bandwith
• Lateral (Azimuth) Resolution
array size
frequency & BW
apodization
![Page 81: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/81.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 81
Point Resolution
• capability of resolving point targets
main lobe width
3 dB resolution: FWHP of main lobe
6 dB resolution: FWHM of main lobe
nofD
rFWHM 22.122.1
![Page 82: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/82.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 82
Contrast Resolution
• capability of resolving regions with different
contrast levels
ratio of power in main lobe to power
in side lobes
Contrast-to-Nose-Ratio:2
2
2
1
21
CNR
![Page 83: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/83.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 83
Delay & Amplitude Quantization
• Delay & Amplitude Quantization side lobe level contrast resolution
• RMS Array/Delay Quantization Errors/ Main Lobe Amplitude
» m=fs/fo=32, N=128 - 59 dB
• RMS Signal-amplitude Quantization Sidelobe Level / Max Image
Amplitude
» N=128, B=8 bits -74 dB
(Peterson & Kino IEEE Trans. UFF, July 1984)
Nmd
6
NBa32
1
![Page 84: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/84.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 84
Real-Time Imaging Constraint
sfiring
cxRangex
frame
firingsx
s
frames1
/2
192
1/1540/20.0220
frame
firings
sfiring
smmxx
frame
firingsx
s
frames
![Page 85: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/85.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 85
Beam Space Sampling
maxmaxmax sin
/2
sin2
sin
sin2
e
e
NN
B
NBNNNNN ert
22
2/145sinsin 0
max
179128 BN
![Page 86: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/86.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 86
Issues
• volumetric scan hardware
• digital systems ADC cost
• flow imaging correlation proces.
• phase aberration resolution
• motion artifacts resolution
![Page 87: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/87.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 87
Dimension of a Transducer Array
This slide is from K. Thomenius’ presentation.
![Page 88: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/88.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 88
3-D Imaging using 2-D Arrays
![Page 89: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/89.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 89
Why 2D?
This slide is from K. Thomenius’ presentation.
![Page 90: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/90.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 90
Volumetric Imaging
# of array channels (NxN) Hardware
32x32 = 1K, 64x64 = 4K, 128x128 = 16K
• 2D sparse arrays with 256 channels currently
available for 3D/4D imaging.
• For ergonomic scanning, the number of cables should be limited by 256 – 512.
# of Beam lines Frame rate
New scanning methods needed.
![Page 91: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/91.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 91
Doppler Frequency
cos2 0fc
vff d
v: flow velocity (?)
f = fd: average Doppler frequency
c: ultrasound velocity
fo: ultrasound frequency
: angle between beam and velocity
![Page 92: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/92.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 92
Correlation Processing
• Differential phase/delay
• Phase of complex correlation coeff.
• Index of max of RF correlation func.
Estimation of motion, phase aberration, flow
k nnk nn
k
nn
nn
ksksksks
ksks
*
11
*
*
1
1,
)()()()(
)()(
k nnk nn
k nn
nn
mksmksksks
mksksm
)()()()(
)()()(
11
1
1,
![Page 93: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/93.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 93
RF Correlation
![Page 94: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/94.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 94
Non-Aberrated Wavefronts
![Page 95: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/95.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 95
Phase Aberration
![Page 96: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/96.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 96
Phase Aberration
Row-1: No aberration., Row-2: 1x aberration., Row-3: 2x aberration
(N=64)
![Page 97: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/97.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 97
Motion!
Maximum Velocity of Heart
Heart Valve cm/s =0.44mm 20 frames/s
– normal 30 cm/s 680 /s 34 /frame
– higher 60 cm/s 1360 /s 68 /frame
– abnormal 100 cm/s 2270 /s 134 /frame
Heart Wall 1-15 cm/s 20-340 /s 1-17 /frame
![Page 98: BYM504E-MK-Basics of Ultrasound Imaging](https://reader034.vdocuments.mx/reader034/viewer/2022051503/577ccf001a28ab9e788e9eb5/html5/thumbnails/98.jpg)
Basics of Ultrasound ImagingMustafa Karaman, PhD 98
End of Session-3