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Page 1: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

1Kiev, Ukraine. 2016

Page 2: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

2

Physical Principles of Modern

Medical Ultrasound Diagnostics

Barannik E.A.

Dept. of Nuclear and Medical Physics

School of Physics and Technologies

Karazin Kharkiv National University

Kiev, Ukraine. 20161804

Page 3: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

3

A few important innovations in ultrasound imaging and their

corresponding technology enablers

HISTORY

Thanks to

its real time capabilities

its non ionizing properties and

its low cost

ultrasound has significantly impacted clinical segments

within radiology, obstetrics, vascular or cardiology etc.

Microprocessor DSP (digital signal

processing chips)

Low cost A/D

convertersMiniaturization Multicore CPU

Page 4: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

4

CONVENTIONAL 2D IMAGING

Each focused beam allows the reconstruction of one image line

The time to build image

Maximum frame rate HzTFRimage

601

max

linesimage N

c

z=T

2

Transmitting: no dynamic focusing Receiving: dynamic focusingP

iezo

ele

ctr

ic

ele

men

ts

S

Receiv

ed

sig

nalsS

ign

al d

ela

ys

Scattere

r

Beam

form

er

Imaged

areaImaged

area

Imaged

areaImaged

area

Lateral

resolution

Final

image

Page 5: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

5

Brightness mode (B-mode): the traditional ultrasound wave is used to image

in gray scale the structures differing by reflection power in accordance with an

amplitude of ultrasound response.

Controlled attenuation parameter (CAP): a novel technology of ultrasonic

attenuation measurement for the evaluation of some liver deceases.

B-MODE & CAP

The set of points having the same reflection power but different depth defines

the attenuation coefficient.

2

11 ln)2(P

Pd

Attenuation coefficient

Page 6: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

6

COMPOUND B-MODE IMAGING

Speckle reduction by an averaging

of a number of equivalent, but not

correlated, images obtained using

different data sets(thyroid gland)

D-mode image formation and

speckle-noises reduction using

angle and frequency compounding

(liver)

• Angle compounding

• Frequency compounding

• Spatial compounding

• Temporal compounding

Averaging process will lead to some

loss of time and spatial resolution

Page 7: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

7

SYNTHETIC APERTURE IMAGING

The retrospective transmit focalization can be done dynamically for each pixel

increasing the quality of the final image compared to physical insonification.

Maximum reachable frame rates increase from 30 Hz to more than 300 Hz.

Ultrafast coherent plane wave compounding. Continuous transmit focus: Ultra high resolution

Conventional transmit focus

Pie

zoele

ctr

ic

ele

ments D

ela

yed s

ignals

Sig

nal dela

ys

Scattere

r

Sig

nal genera

tor

Imaged

areaImaged

area

Imaged

area

Final

image

Page 8: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

8

HARMONIC IMAGING

Tissue Harmonic Imaging frequently reduces

significantly image artifacts and provides

better contrast resolution

Fundamental frequency

1860

Riemann G. F. B.

Second harmonic

2)( PP

2PP + =

22P

In most medical applications it cannot be

assumed that the linearity condition is satisfied

xv

A

Bcc )

21(

0

,)(2

0000c

PA

0

2

2

002

2

2

0)()(

cPB

Page 9: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

9

DOPPLER IMAGING

Ultrasound Doppler is widely used in clinical practice to study the vascular

system, to determine blood flow velocity and direction, and to image soft tissues

The most common imaging formats:

Color Flow Imaging

Color Power Imaging

Spectral Doppler

Doppler spectral width depends on:

wavelength

Doppler angle

sample volume size

mean flow velocity

acceleration of blood flow

velocity profile within sample volume

flow turbulence

time window duration

cos2 V

=fD

V

Doppler frequency

Page 10: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

10

CFI & CPI

Color Flow Imaging (CFI) – value and direction of velocity, color-coded and

superimposed on the B-Mode image

Color Power Imaging (CPI) – the intensity of the Doppler signal is related to

the number of moving reflectors, color-coded, superimposed on the B-mode

image, generally very sensitive for low flow

Zone sonography

Page 11: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

11

SPECTRAL DOPPLER

In the case of low mean flow velocities the width of the resulting Doppler

power spectrum is defined mostly by the wavelength of the incident field, the

Doppler signal duration and the acceleration of scatterers

In the opposite case the size of sample volume and the value of velocity

itself are much more essential

Doppler spectrogram

Page 12: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

12

M-MODE IMAGING

The pulse wave propagation is a diagnostic tool already used by the Greeks in

the 4th century BC and remarkably developed for two millennia by the Chinese.

Predictor of the cardiovascular risk: arterial wall stiffness.

Two points of the carotid artery wall have the same displacement with a

time shift . The velocity of the pulse wave is and characterizes

a wall artery stiffness.

t txC

Motion mode (M-mode)

Precise Doppler measurement of the carotid artery wall motion

Page 13: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

TISSUE ELASTICITY

P

P P

P

P

P

P

PP

h

Δh

– bulk modulus (ΔV ≠ 0)

– shear modulus (ΔV = 0)

– compressional Young’s modulus

compressional wave velocity

shear wave speed

compressional Young’s modulus

K

μ

E

,3μεPE

ρKc

ρμct

hΔhε Tissues Е, kPa

Breast

normal fat 18-24

normal grandular 28-66

fibrous tissue 96-244

carcinoma 22-560

Prostate

normal anterior 55-63

normal posterior 62-71

BPH 36-41

carcinoma 96-241

Livernormal 0.4-6

cirrhosis 15-100

The relative range of values between

deferent soft tissues for the shear modulus

is several orders of magnitude greater than

that for the bulk modulus

Page 14: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

14

Simply operated by lightly pressing a probe to the surface of the body, the

hardness of tissue can be displayed color in real-time.

Compression elastography is not quantitative method.

COMPRESSION ELASTOGRAPHY

Cross-correlation-based

tracking algorithms of

movement detection

B-mode CE-mode

Page 15: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

15

Acoustical streaming in the water starch solution and shear wave in elastic

media like tissue, which were induced by the acoustic radiation force.

ACOUSTIC RADIATION FORCE

If sufficient energy if applied at the focus of an ultrasound beam, tissue can

be remotely pushed in the direction of the ultrasound wave propagation. A

transient shear wave that propagates transversally is generated.

Acoustic radiation force: , - temporal average intensityTA

Ic

αF

2

TAI

Page 16: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

16

SHEAR WAVE EXCITATION

Shear waves are amplified in a

Mach cone shape (in yellow), which

increases the propagation distance

of shear waves while minimizing

acoustic power

Wavefront

Page 17: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

17

SHEAR WAVE SPEED

Frequency-domain Form of Wave Equation

Artannlabs & Supersonic Imagine (France)Karazin KhNU & Ultrasign (Ukraine)

Two-dimensionalOne-dimensional

0),(

),(2

222

x

xu)

ρ

ηiω(cxuω

t

0

),(2

x

xu)

ρ

ηiω(ciωu(ω,x)

t

Karazin KhNU & Artannlabs (USA)

STCU #865, #865(C), P-150

u(yn-1,t)

u(yn,t)

u(yn+1,t)

t

Tissue displacement in points with different radial coordinate in the focal plane

allows defining of the first and second derivatives for shear speed estimation.

Page 18: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

18SWEI gives important quantitative information on the elastic

properties of tissue and improves cancer diagnostic

Breast: red – cancer, blue – no cancer

Abdominal cavity: soft

tissue metastases

SHEAR WAVE ELASTICITY IMAGING

(SWEI)

Page 19: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

19

MULTI-MODALITY IMAGING

True image of breast phan-

tom: gray – no cancer,

red – cancer

Compound image: gray–

no cancer, red – cancer,

green – future cancer

Electrical impedance tomography

Inverse scattering –

acoustic absorption

Transmission tomo-

graphy – speed of

sound

Feature space

Page 20: Kiev, Ukraine. 2016 - Taras Shevchenko National University ...science.univ.kiev.ua/french-ukrainian/lections/EB.pdf · Medical Ultrasound Diagnostics Barannik E.A. Dept. of Nuclear

18

Thank you for attention!