In this presentation dr. Masciotra shows how the speed of sound selection in US imaging does change the informations of US data, both qualitative (morphology, echogenicity, spatial and contrast resolution) and quantitative (density of vessels, stiffness map) of the tissues examined. In questa presentazione il dr. Masciotra analizza sulle immagini di casi clinici gli effetti della scelta della velocità del suono sulla qualità delle informazioni dei dati ecografici. Come si può vedere il parametro della velocità del suono condiziona in maniera sensibile le informazioni sia qualitative (morfologia, ecostruttura, risoluzione spaziale e di contrasto) che quantitative (densità dei vasi e proprietà meccaniche come l'elasticità) dei tessuti esaminati.

1. Antonio Pio Masciotra
Campobasso – Molise – Italy
Email
antoniomasciotra@yahoo.it
Website
www.masciotra.net
YouTube Channel
https://www.youtube.com/channel/UCgCj21nKGAhR997Ia3-QegQ
How speed of sound adjustments change the informations of
Bidimensional US, Color/Powerdoppler and Shear Wave Elastography

2. The local sound speed is the measure of how fast a sound pressure wave travels through a local volume of tissue.
A linear relationship exists between the sound speed and density for a range of soft tissues.
Breast glandular tissue has a higher sound speed than breast fat.
Patients with dense breasts tend to have a considerably higher overall breast sound speed.
Kossoffet al measured the overall average composite (fat and gland) breast sound speed.
The mean values reported were :
1.468 m/s in postmenopausal women
1.510 in premenopausal women
These differences are consistent with the higher fraction of glandular tissue in younger women.
This approach used a differential method to calculate the sound speed in a sample, where the path length between transmitting and receiving transducers was computed using the known sound speed of water.
Other groups have used the same differential method in measuring the sound speed of a sample using both transmissionand reflection US.
Breast cancers have an even higher density and sound speed, likely due to changes in cancerous tissue mechanical and elastic properties.
Mean values from published sound speed reports are as follows:
Fat 1.478 m/s
Glandular breast 1.510 m/s
Benign breast tumors 1.513 m/s
Malignant breast tumors 1.548 m/s
Then sound speed can be used to assess breast density
and potentiallydetectbreastcancer.

3. Tissue
Density
( kg/m3 )
Speed
(m/s)
Impedance
(rayls)
Attenuation
dB/(MHz x cm)
Lung
400
0,26
Fat
920
1.450
1,35
0,48
Breast
0,75
Water
1.000
1.484
1,52
0,0022
Brain
1.030
1,55-1,66
0,6
Kidney
1.040
1.560
1,62
1,0
Blood
1.060
1.570
1,62
0,20
Liver
1.060
1.570
1,64-1,68
0,50
Spleen
1.060
1.570
1,65-1,67
0,50
Soft tissue(average)
1.540
0.54
Muscle
1.070
1575-1590
1,65-1,74
1,09
Fibroustissue
1,57
Tendon
4,7
Bone
1.380-1.810
4.080
3,75-7,38
6,9-9,9
In thistablethe keypointisthathigherdensitytissuesshow alsohigherspeedof sound, impedanceand attenuation(with onlya fewexceptions).

4. TissueTuner™ allows you to adjust the receive parameters
associated with the assumed speed of sound of ultrasound in the body.
Adjusting the speed of sound parameter to match the type
of tissue being interrogated results in increased spatial and lateral resolution.
USCT provides three types of images:
•reflection images
•attenuation images
•speed of sound images.
Reflection images reveal changes in the echotextureand are therefore able to image the surface of tissues.
This results in the visualization of the morphology.
Attenuation and speed of sound images are expected to provide a tissue characterization.
As shown in the figure, a high speed of sound is expected to be an indicator of cancerous tissue.
Additionally, the combination of speed of sound information with attenuation information might further improvethe specificity.
Relation between the ultrasonic properties speed of
soundand attenuation for different breast tissues.

5. Antonio Pio Masciotra
Campobasso – Molise – Italy
Email
antoniomasciotra@yahoo.it
Website
www.masciotra.net
YouTube Channel
https://www.youtube.com/channel/UCgCj21nKGAhR997Ia3-QegQ
Breast cancer
How speed of sound adjustments change the informations of
Bidimensional US, Colord/Poweroppler and Shear Wave Elastography

6. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
B scanimage
15-4 MHz Linear Probe

7. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
Colordoppler
15-4 MHz Linear Probe

8. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
2D SW Elastography
15-4 MHz Linear Probe

9. C = 1.420 m/s
C = 1.600 m/s
C = 1.660 m/s
C = 1.420 m/s
C = 1.600 m/s
C = 1.660 m/s

10. C = 1.420 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.600 m/s

11. C = 1.420 m/s
C = 1.660 m/s
3D SW Elastography
16-5 MHz Linear Probe

12. Antonio Pio Masciotra
Campobasso – Molise – Italy
Email
antoniomasciotra@yahoo.it
Website
www.masciotra.net
YouTube Channel
https://www.youtube.com/channel/UCgCj21nKGAhR997Ia3-QegQ
Thyroid cancer
How speed of sound adjustments change the informations of
Bidimensional US, Color/Powerdoppler and Shear Wave Elastography

13. •Woman 18 yearsold, since3 yearsaffectedby Hashimotothiroiditis, butwithoutnodulesuntil8 mothsbefore
•Actuallya solidnodulein right lobewith microcalcifications, intranodularvesselsand stiffareasatSW elastography(>90 kPa)
•Suspiciouslymphnodein right middle laterocervicalsite

14. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
15-4 MHz Linear Probe
B scanimage

15. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
15-4 MHz Linear Probe
Colordoppler

16. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
Lin. 15-4 MHz
1.420 m/s
1.480 m/s
1.540m/s
1.600 m/s
1.660 m/s
Meanstiff.
24.3
29.3
29.0
28.1
24.6
Min. stiff.
0.1
0.1
0.1
0.1
0.1
Max. stiff.
81.5
71.8
92.9
111.1
84.6
St. Dev.
19.9
17.6
16.7
21.8
18.4
Area
1.25
1.53
1.55
1.55
2.03

17. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
10-2 MHz Linear Probe
B scanimage

18. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
10-2 MHz Linear Probe
Colordoppler

19. Antonio Pio Masciotra
Campobasso – Molise – Italy
Email
antoniomasciotra@yahoo.it
Website
www.masciotra.net
YouTube Channel
https://www.youtube.com/channel/UCgCj21nKGAhR997Ia3-QegQ
Liver hemangioma
How speed of sound adjustments change the informations of
Bidimensional US, Color/Powerdoppler and Shear Wave Elastography

20. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
6-1 MHz ConvexProbe
B scanimage

21. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
6-1 MHz ConvexProbe
Powerdoppler

22. C = 1.660 m/s
C = 1.600 m/s
C = 1.420 m/s
C = 1.480 m/s
C = 1.540 m/s
6-1 MHz ConvexProbe
Shearwaveelastography

23. How speedof sound adjustmentschangethe informationsof
BidimensionalUS, Color/Powerdopplerand ShearWaveElastography
Take Home messages
Itdoesn’texista common speedof sound presetbringingoptimalinformationsbothqualitative (morphology, spatialand contrastresolution) and quantitative (depictionof vesselsand stiffness) in allthe tissues, in allthe applicationsand with allthe probes
In general slowerspeedsof sound givemore detailedqualitative informationswhilefasterspeedsof sound seemto givea bettershearwavemap
Vascularmapseemsto be notinfluencedby the speedof sound selection
The abovepointsare truein the US studyof focaldiseases
In myopinion the US studyof diffuse diseasedoesrequiredetailedand large data acquisitionto wellunderstandwhichisthe best speedof sound choiceto guaranteethe accuracyand the repeatibilityof the stiffnessquantificationin conditionslikethe evaluationand followup of liverfibrosis.

24. I experienced sound speed was more influenced on Breast images than on abdomen.
It may be because of high frequency (= short wave length) imaging, which is more sensitive to the wave shift.
And the optimum speed for breast is generally lower (1480) than liver (1540).
Regarding SWE, since the sound speed of shear wave is much slower than ultrasound wave, speed of sound setting doesn’t effect on the shear wave propagation in the physically point of view.
But the practical point of view, shear wave is always measured by the method same as Doppler measurement.
So, if in the wrong sound speed, Doppler’s image quality in terms of spatial resolution becomes worse.
I think this phenomena will effect on the precision of shear wave measurement.
Actually US imaging is based only on the assignment of speed of sound speed's value only to received parameters, while it's not used in changing the beamformer(speed of sound in transmitted parameters).
And the process of back projection used in CT scan for the density map reconstruction of the body is not used in the image formation US based.
So I believe that actually US is only at 20% of its potentiality.
We always manage with time, velocities and paths!
Compressional waves travel at a speed of 1.540 m/s
Shear waves travel at a speed of a few m/sdin arteries travels at around 1 m/s speed
Blood in veins travels at a few cm/s.
Both compressional and SW hasten in cancer and 'hard (or denser) tissues'.
Actually the system of US imaging is similar to a marathon race in which the judge has the chronometer and measures the time passed in the completion of the whole path.
Then he knows only the mean velocity, being unknown the speed in the different segments of the path.

25. Antonio Pio Masciotra
Campobasso – Molise – Italy
Email
antoniomasciotra@yahoo.it
Website
www.masciotra.net
YouTube Channel
https://www.youtube.com/channel/UCgCj21nKGAhR997Ia3-QegQ
How speed of sound adjustments change the informations of
Bidimensional US, Color/Powerdoppler and Shear Wave Elastography