Download as PDF, PPTX
![17
Laminar flow
v r = 𝑣0[1 −
𝑟
𝑅
2
]
Parameter Value
Number of Tx/Rx channels 128
Array pitch 0.2 mm
Sampling rate 32 MHz
Center frequency 8 MHz
Plane wave angle −𝟖𝒐, 𝟎𝒐, 𝟖𝒐
Pulse repetition frequency 10 kHz
Radius of blood vessel (R) 4 mm
Peak flow velocity (𝒗𝟎) 0.2 m/s
Ensemble size 10
Simulation (Field II)](https://image.slidesharecdn.com/vfiwebinarfinal1-240509184849-b68a1482/85/May-9-2024-Enhanced-Ultrafast-Vector-Flow-Imaging-VFI-Using-Multi-Angle-Plane-Waves-17-320.jpg)
![20
Parameter Vessel 𝜽 = 𝟗𝟎𝒐 Vessel 𝜽 = 𝟓𝟓𝒐
Array element 128 128
Array pitch 0.2 mm 0.2 mm
Sampling rate 32 MHz 32 MHz
Center frequency 8 MHz 6 MHz
Pulse repetition
frequency
10 kHz 9 kHz
Ensemble size 10 10
Plane wave angle [−16o
, 0o
, 16o
] [16o
, −8o
, 0o
, 8o
, 16o
]
Source: https://jdigitaldiagnostics.com/DD/article/view/76511#tabs-5
Source: https://www.s-sharp.com/uploads/
root//Prodigy256system20201126.jpg
in vitro Experiments
Vessel 𝜽 = 𝟓𝟓𝒐
Vessel 𝜽 = 𝟗𝟎𝒐](https://image.slidesharecdn.com/vfiwebinarfinal1-240509184849-b68a1482/85/May-9-2024-Enhanced-Ultrafast-Vector-Flow-Imaging-VFI-Using-Multi-Angle-Plane-Waves-20-320.jpg)
![25
Parameter Value
Number of Tx/Rx channels 128
Array pitch 0.2 mm
Sampling rate 32 MHz
Center frequency 8 MHz
Pulse repetition frequency 12 kHz
Ensemble size 10
Plane wave angle [−16o
, 0o
, 16o
]
Source: https://www.docknet.jp/media/medical-checkup-23/
in vivo Experiments
Carotid arteries were measured](https://image.slidesharecdn.com/vfiwebinarfinal1-240509184849-b68a1482/85/May-9-2024-Enhanced-Ultrafast-Vector-Flow-Imaging-VFI-Using-Multi-Angle-Plane-Waves-25-320.jpg)
Uploaded byScintica Instrumentation
(May 9, 2024) Enhanced Ultrafast Vector Flow Imaging (VFI) Using Multi-Angle Plane Waves
The document discusses enhanced ultrafast vector flow imaging (VFI) using multi-angle plane waves and its applications in medical ultrasound, particularly in hemodynamics visualization. It outlines various techniques and technologies, including speckle tracking, and provides experimental findings using a 128-channel research platform called Prodigy. The conclusion highlights the advantages of VFI over conventional Doppler imaging for comprehensive flow analysis and the integration of advanced imaging methods for improved results.
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(May 9, 2024) Enhanced Ultrafast Vector Flow Imaging (VFI) Using Multi-Angle Plane Waves
- 1. Enhanced Ultrafast Vector FlowImaging (VFI) Using Multi-Angle Plane Waves Geng-Shi Jeng Associate Professor Institute of Electronics National Yang Ming Chiao Tung University, Taiwan
- 2. What You CanLearn • Ultrasound clinical Doppler imaging: Overview and limitations • Advanced vector flow imaging (VFI): Techniques and applications • Integration of ultrafast imaging and speckle tracking with VFI for enhanced flow visualization • Experimental findings utilizing a 128-channel research platform (Prodigy) for comprehensive flow analysis
- 3. Medical Ultrasound • 1-15MHz frequency pulse-echo imaging system • B-mode (Brightness): Anatomy • Doppler-mode: Motion • Vascular & Cardiac: Color Doppler, Spectral Doppler, Vector Flow • Myocardium: Tissue Doppler, Strain Rate Imaging Color Doppler B mode 3D B-mode Tissue Doppler Strain Rate Imaging Doppler mode
- 4. Medical Imaging Systems ModalityReal- time Non- Radiation Flow Velocity Mobility 3-D Cost CT ◎ 100k-300k X-ray ◎ 120k-235k MRI ◎ ◎ ◎ ◎ 150k-2M PET ◎ >2M Ultrasound ◎ ◎ ◎ ◎ ◎ ◎ 5k-70k
- 5. Doppler Effect Christian Doppler(1803–1853) https://commons.wikimedia.org/wiki/ https://www.shutterstock.com/zh/image-vector/education-chart-physic-doppler- effect-sound-658148101 Frequency shift ∝ Velocity
- 6. Probe Beam direction Blood Flow 200 400600 800 1000 1200 1400 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 Tx Rx 𝑓𝑐 𝑓𝑐 +𝑓𝑑 Doppler Ultrasound Tx Rx 𝒇𝒅 = 2𝑓𝑐𝑣𝑐𝑜𝑠𝜃 𝑐 Doppler shift Velocity vector Center frequency Sound velocity Doppler angle Axial velocity Lateral velocity Velocity vector 𝜃 𝒗𝒔𝒊𝒏𝜽 𝒗𝒄𝒐𝒔𝜽 𝒗
- 7. Color & PowerDoppler Color Doppler Color Doppler Power Doppler • Color Doppler • Both velocity amplitude and direction (axial only) are color coded. • Power Doppler • Doppler energy is color coded. No velocity magnitude/direction.
- 8. Spectral Doppler Continuous Wave(CW) Doppler Pulsed Wave (PW) Doppler Velocity distribution (spectrum) of a specific direction (CW Doppler) or gated depth (PW Doppler) as a function of time
- 9. Color Doppler onResearch Platform Cardiac 4-chamber view Carotid artery
- 10. Commercial Vector FlowImaging (VFI) https://www.facebook.com/MindrayNorthA merica/videos/2007450559399979/ V flow BSI Mindray BK Medical GE Method Multi-angle Beam Doppler Transverse Oscillation (TO) Doppler Speckle Tracking Visualization Trajectory Fixed Arrow Trajectory Imaging Acquisition Ultrafast Imaging N/A Ultrafast Imaging
- 11. Ultrafast Imaging (Multi-anglePlane Waves) M. Tanter, F. Mathias Fink,"Ultrafast imaging in biomedical ultrasound." IEEE UFFC, 2014. No. of plane waves ↑ Imaging quality ↑ Frame rate ↓ Plane Wave Imaging Focused Beam
- 12. • Vector flowimaging (VFI) • Multi-beam, speckle tracking, lateral oscillation,… • Allow detailed hemodynamics • Frame rate > 1kHz • Multi-angle plane-waves + Doppler (Mindray) • Combining axial velocities for individual steered plan waves • Drawback (Doppler or Autocorrelation estimators) • Bias, ensemble-dependent variance (8-12 samples), spectral aliasing • Visualization: Trajectory or fixed arrow? Robust? VFI Good Enough? Ultrafast imaging + Robust velocity estimator + Robust particle trajectory Need
- 13. • Develop ultrafastVFI based on speckle tracking (ST) • Plane wave imaging using 3-5 angles • Velocity vector • Combining axial velocity estimates for individual plane waves using weighted least squares (WLS). • Robust superresolution-like particle imaging • Speckle similarity as a quality index Our Solution
- 14. 14 Search region Kernel Target Reference 𝐍𝐂𝐂 (𝐐𝐮𝐚𝐥𝐢𝐭𝐲𝐢𝐧𝐝𝐞𝐱) 𝐀𝐱𝐢𝐚𝐥 𝐯𝐞𝐥𝐨𝐜𝐢𝐭𝐲 (𝐆𝐨𝐨𝐝!) Disp. 𝐋𝐚𝐭𝐞𝐫𝐚𝐥 𝐯𝐞𝐥𝐨𝐜𝐢𝐭𝐲 (Bad!) Speckle Tracking NCC: Normalized Cross- Correlation
- 15. NCC: Normalized Cross- Correlation ProposedMethod (LS-ST) 3-angle plane wave imaging Axial velocity estimate using ST Vector estimate using least squares
- 16. Transducer 𝑣𝑐𝑜𝑠 𝛼 −𝜃2 = 𝑢𝑎2 𝑣𝑐𝑜𝑠 𝛼 − 𝜃3 = 𝑢𝑎3 𝑣𝑐𝑜𝑠 𝛼 − 𝜃1 = 𝑢𝑎1 𝜽𝟏 Transducer 𝒗𝐳 𝜽𝟐 Transducer 𝜽𝟑 𝐀𝑣 = 𝑢 ⇒ 𝑐𝑜𝑠𝜃1 𝑠𝑖𝑛𝜃1 𝑐𝑜𝑠𝜃2 𝑠𝑖𝑛𝜃2 𝑐𝑜𝑠𝜃3 𝑠𝑖𝑛𝜃3 𝑣𝑧 𝑣𝑥 = 𝑢𝑎1 𝑢𝑎2 𝑢𝑎3 ( 𝒗𝒛: 𝑣𝑐𝑜𝑠𝛼 𝒗𝒙: 𝑣𝑠𝑖𝑛𝛼) NCC-weighted LS → 𝑣 = (𝐀𝑇 𝑊𝐀)−1 𝐀𝑇 𝑊𝑢 Unknowns Measurement Unknowns NCC-weighted Least Squares Plane wave 𝜽𝟏 Plane wave 𝜽𝟐 Plane wave 𝜽𝟑 NCC: Normalized Cross- Correlation 𝒗𝒙 𝑢𝑎1 𝑢𝑎2 𝑢𝑎3
- 17. 17 Laminar flow v r= 𝑣0[1 − 𝑟 𝑅 2 ] Parameter Value Number of Tx/Rx channels 128 Array pitch 0.2 mm Sampling rate 32 MHz Center frequency 8 MHz Plane wave angle −𝟖𝒐, 𝟎𝒐, 𝟖𝒐 Pulse repetition frequency 10 kHz Radius of blood vessel (R) 4 mm Peak flow velocity (𝒗𝟎) 0.2 m/s Ensemble size 10 Simulation (Field II)
- 18. Simulation Result at60° LS-ST Conv-ST (Conventional speckle tracking) -0.2 -0.1 0 0.1 0.2 (m/s) LS-ACF m/s 𝐕𝐚𝐱𝐢 𝐕𝒍𝒂𝒕 𝐕𝐯𝐞𝐜 m/s m/s 𝑽𝐯𝐞𝐜 (Velocity Vector)
- 19. 19 Ground truth LS-ACFLS-ST Particle Flow Imaging at 60°
- 20. 20 Parameter Vessel 𝜽= 𝟗𝟎𝒐 Vessel 𝜽 = 𝟓𝟓𝒐 Array element 128 128 Array pitch 0.2 mm 0.2 mm Sampling rate 32 MHz 32 MHz Center frequency 8 MHz 6 MHz Pulse repetition frequency 10 kHz 9 kHz Ensemble size 10 10 Plane wave angle [−16o , 0o , 16o ] [16o , −8o , 0o , 8o , 16o ] Source: https://jdigitaldiagnostics.com/DD/article/view/76511#tabs-5 Source: https://www.s-sharp.com/uploads/ root//Prodigy256system20201126.jpg in vitro Experiments Vessel 𝜽 = 𝟓𝟓𝒐 Vessel 𝜽 = 𝟗𝟎𝒐
- 21.
- 22. Real-time Implementation Pulse SequenceGUI Python Interface
- 23. LS-ACF LS-ST Arrow-based VFIvs. New Particle Imaging
- 24. 24 LS-ACF LS-ST Arrow-based VFIvs. New Particle Imaging
- 25. 25 Parameter Value Number ofTx/Rx channels 128 Array pitch 0.2 mm Sampling rate 32 MHz Center frequency 8 MHz Pulse repetition frequency 12 kHz Ensemble size 10 Plane wave angle [−16o , 0o , 16o ] Source: https://www.docknet.jp/media/medical-checkup-23/ in vivo Experiments Carotid arteries were measured
- 26. 26 Arrow-based VFI ColorDoppler w/ angle correction LS-ACF Conv-ST LS-ST Pulsed Wave (PW) Doppler
- 27. 27 2mm 2mm (LS-ST) Arrow-based VFI vs.New Particle Imaging
- 28. Blood Pressure &Flow Measurements Blood pressure Cross-section area (A) Volume flow rate (Q) QA loop
- 29. What You Needto Know • Conventional Doppler imaging only detects 1-D velocity component. • VFI enables visualization of velocity vectors using trajectory or arrow- based approaches. • Ultrafast imaging + VFI allow for comprehensive hemodynamics evaluation. • Speckle tracking-based VFI provides a promising alternative to current Doppler-based VFI techniques. • Prodigy array research platform facilitates seamless integration of pulse sequences and developed algorithms for advanced flow imaging analysis.
- 30. Q&A WWW.SCINTICA.COM INFO@SCINTICA.COM Please enter yourquestions in the Q&A section Thank You!